The Success Of Alexander The Great - 1374 Words

Alexander the Great is one of the most successful military commanders of all time. Some may attribute Alexander’s success to his inheritance of the great Macedonian kingdom and military from his father, Philip II. Although there is no doubt that this timely inheritance was a key factor in his success, it was his military skills and generalship that gave him the ability to effectively utilize the groundwork laid by his father. In order to fully understand the success of Alexander, we must first look back to the influence and success of his father, Philip II. Greece had been unified under the League of Corinth, so when Alexander assumed the throne, he did not need to worry about any fighting to the south. Philip took the small and insignificant country of Macedon and turned it into one of the greatest military powers in the ancient world. When Philip was assassinated, Alexander inherited an extremely skilled and modernized army he could use to make his father’s dream of defeating the Persians come true (Martin, Ancient Greece p.221). Philip’s reforms to the Macedonian army include reorganizing the structure and the use of troops and improving weaponry and tactics (Potter, Lecture 13 March 2015). The Macedonian phalanx was a great improvement over the hoplite phalanx used in Greek warfare because of two reasons. Well-trained soldiers, known as phalangite, wore lighter armor that enabled them to move quicker and utilize their new, longer spears known as sarissa, whichShow MoreRelatedAlexander The Greats Influence On The World1431 Words   |  6 PagesAlexander the Great Occasionally history shows that the world does not have many people that could be entered in the history. And Alexander the Great was one of these people. During his childhood Alexander had great teachers who taught him how to use and how to choose great politics, diplomacy and, how to win the war if that day would come. For many years Alexander the Great studied how to control everything and how to be ready to do anything that might be needed. At the age of sixteen he had toRead MoreWhat was so Great About Alexander the Great?810 Words   |  3 Pages Alexander the Great, also known as Alexander III of Macedon, was born in Pella, the ancient capital of Macedonia in 356 BC and was handed down his reign when his father, Phillip II was murdered in 336 BC by his bodyguard. His father was out most of the time trying to extend his kingdom therefore Alexander was left with his mother, Olympias, who was very emotionally close to her son and had a tendency to spoil him. Alexander was hand ed down a trained, strong and powerful army with excellent generalsRead MoreAlexander the Great Essay1747 Words   |  7 PagesAlexander the Great, son of King Philip II of Macedonia, underwent a journey of overwhelming odds. Alexander led his army through multiple victories across the Persian territories of Asia Minor, Syria and Egypt without the agony of a single defeat. A noteworthy battle of Alexander was the Battle of Gaugamela in 331 B.C.E. The Battle of Gaugamela is significant because it ended Darius’s rule over Persia. [new par.] There are several forces and factors that contribute in making Alexander the GreatRead MoreAlexander the Great Essay1358 Words   |  6 Pagesman named Alexander III of Macedon or more commonly known as, Alexander the Great. His father, King Phillip II, took the throne of Macedonia in 359 B.C.E and was able to turn Macedonia into the strongest military power in the entire Greek world. Macedonia was a state in the north eastern region of Greece. Alexander III of Macedon was born in 356 B.C.E in Pella; the ancient capital of Macedonia, Alexander grew up in the shadow of his father’s success in transforming Macedonia into a great militaryRead MoreAlexander the Great Conquest848 Words   |  4 Pages Alexander the Greats Distribution of Culture Someone who has abilities above the normal or average person is considered great. In this case, were talking about Alexander the infamous Greek invader. Alexander the Great was a man of conquest and curiosity. By the age of twenty he had already conquered many of his local Grecian city states and had established himself as a leader. His desire to conquer and explore grew as he aged. As he travelled he took along with him the morals and customs ofRead MoreAlexander II And Alexander The Great1642 Words   |  7 Pagessomeone who is good at planning tactics; Philip II and Alexander the Great would not fall under this name because they were not good at planning tactics, they were disputed to be the best at planning them. Alexander III the Great was born in 356 BC in the capital of Macedonia; Pella. Growing up Alexander watched his father turn Macedonia into a great military power . Philip II was the first to create an unstoppable Macedonian army and his son Alexander would further exp and the efficiency and power ofRead MoreCaesar, Hannibal, and Alexander the Great Essay1269 Words   |  6 PagesIt was the leadership of Caesar, Alexander, and Hannibal that heavily influenced the Roman society, the ancient world, and the western civilization. Ambition drove Alexander the Great to conquer the unconquered, propelled Caesar to the top of the political spectrum with no birthright, and helped Hannibal defeat a dominent society in the ancient world. It was Julius Caesars successful military tactics, his drive to the top of the political society, and his succession without the right, privilegeRead MoreAlexander The Great Of The Empire929 Words   |  4 PagesIn the Late 4th century, BC Alexander the great was a very popular and was a great king to everyone. He was one of the best kings ancient Greece had. His mindset and goal after his dad died was to take over the Persian empire because this is what his dad wanted to do, he moray thought that this is what he should do to make his dad proud. This all started at the age of 20. Alongside Alexander the Great. The Roman empire took a lot longer to conquer due to its size. The Persian empire was taken overRead MoreMacedonian Culture And Greek Culture1442 Words   |  6 Pagessimilar to the Greek culture. Certainly, both of those cultures are not identical; they do have differences, yet by looking at the women’s independent role and freedom among the society and the military success of those cultures, it is clear that both of them resemble. For instance, Alexander the Great thought that he was a descendant of a Greek God and always wanted to show how Greek he was. This might be the reason why the Macedonian culture is very similar to the Greek culture. In both culturesRead MoreThe Victory Of The Battle Of Issus, And The Conquering Of Tyre922 Words   |  4 PagesHowever, the accuracy of the film takes a turn when transitioning from Alexander taking over gaining more power and taking over the thrown and the battle of Gaugamela. Covering Alexander’s accomplishments concerning the defeat of the rebellion of Thebes, the battle of Issus, and the conquering of Tyre would have drastically increased the running time of the film, but these events are important to understanding Alexander’s overall triumph. Before his father, Philip, died a Greek city called Thebes

What Every Body Is Saying About College Paper Writers Is Wrong and Why

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Experimental & Numerical Study Of Lift with Airfoil Diagram

Question: Describe about the Experimental and Numerical Study of Lift and Drag of an Airfoil. Answer: Introduction A number of research efforts have been inclined towards the airfoil drag and lift coefficients using a cross flow fan at varying boundary parameters by numerical and experiment means. Several experiments and numerical studies carried out reveal that many factors influence the value obtained for the drag and lift coefficients. As discussed in the paper, airfoil creates a great lift at lowest frontward velocities and reflects a great potential for both the scenarios of vertical landing and takeoff and that of quick landing and takeoff. Besides, the experimental results obtained reveal that the pitching moment and lift coefficients of the airfoil profile rise and the momentous drag coefficient declines as the rotational velocity of the airfoil fan declines. This means that in aeromechanics, the pitching moment constant improvement depicts that the aircraft gathers a relatively improved stability at comparatively superior rotational velocities. Significance of the Problem It is important to understand the parameters that govern the landing and takeoff of an aircraft in the modern aircraft mechanics and design. The study on drag and lift is crucial in aerodynamics today since it helps in understanding the pressure distribution on the airfoil profile. The information helps in the design of the airfoil fan and the determination of the appropriate pitching moment and the desired airfoil velocity. Literature Review Several researchers have undertaken to examine on the experimental and numerical study of drag and lift of an airfoil critically. Different researchers come up with different findings on the topic. To start with, Ã… ¾ahin and Acir (2015) of the Department of Energy Systems Engineering conducted an experiment at the Faculty of Technology, in the University of Gazi aimed at investigating the NACA 0015 transient dynamics, and carried out their measurements in an open wind tunnel. The parameters of the experiment were such that the wind velocity interval ranged between 3.1 and 28 m/s with an estimated cross-section of 30 cm by 30 cm m and a tunnel test of approximately 400 cm long. The diagram below shows the drag and lift of airfoil. As demonstrated in the figure, there are 4 major forces that act on the aircraft while in the air. In the case of a powered aircraft, there is a thrust force acting on the aircraft. The other forces operating on the aircraft include the weight of the aircraft, lift, and drag. However, the most important forces for analysis are drag and lift. The aircraft wing is the main contributor to the resultant drag and lift owing to the streamline shape of the airfoil. The streamline shape of the airfoil assists in providing great lift values at minimum drag for specified flight conditions. In addition, the wings of the conventional aircraft employ moving surfaces such as slats and flaps in most cases to adapt to the varying prevailing conditions. The other specifications of the NACA 0015 were 100 mm for both the spanwise length and the chord length. With a wind velocity of 10 meter per second and an attack angle in the range of 0 and 20 degrees, the experimental results showed that for an attack angle of 16 degrees, the highest drag and lift coefficients were 0.15 and 0.75 respectively. The optimum Cl/Cd ratio was registered at 8 degrees. The methods employed in estimating the non-dimensional coefficients were Drag coefficient . (1) (Askari Shojaeefard, 2012) Lift coefficient (2) (Dedeic, 2014) Where L is the lift, D is the drag, Cl is the lift coefficient, Cd is the drag coefficient, c is the chord length of the airfoil, V is the wind velocity, is the air density. The graphs below shows a comparison of the results obtained from this experiment with the numerical values. Figure 3Cl/Cd ratio for different attack angles Some important terms and concepts help in the determination of the lift and drag of the airfoil. In a more general sense, an airfoil has both a trailing edge and a leading edge that is basically designed with variant bottom and top surface curvatures to accelerate the flow that results from the induced pressure gradient generating a lift. The chord of the airfoil is the line that connects the trailing edge and the leading edge. In addition, a camber is the greatest distance covered between the chord and the surface of the airfoil as outlined in its profile. The airfoils chord length is the maximum length of the airfoil. Moreover, the attack angle of the airfoil is essentially the angle that is subtended between the relative fluid flow direction and the chord in a horizontal. Moreau, Jolibois, and Benard (2009) undertook a similar research using NACA 0015 airfoil model that was used by Ã… ¾ahin and Acir (2015) by mounting a Dielectric Barrier Discharge. In their experiment, they investigated the impact of both unsteady and steady drag and lift coefficient actuations using force measurements that were time-averaged. They found out that it is possible to delay the stall regime by 1 or 2 degrees while at the same time decreasing the drag coefficient. In order to investigate the stall flutter at minimum Reynolds numbers, Bhat and Govardhan (2013) conducted an experiment using a NACA 0012 airfoil model. The diagram below shows the wind blades of the wind turbine and the lift and drag. The flow fields and forces were measured by oscillating the airfoil at reduced Reynolds numbers of approximately 104. The airfoil underwent pitch oscillations with small amplitudes, , with great m known as angle of attack at varying frequencies, f. Energy transfer from the flow to the airfoil were computed by directly measuring the varying loads on the airfoil during oscillation. The researchers established that at low chord length (low Reynolds number), there was stall flutter and airfoil excitation. Wang, Ingham, Ma, Pourkashanian, and Tao (2010) also conducted a similar experiment using NACA 0012 model of airfoil by investigating the dynamic stall scenario in a 2D computational perspective at reduced Reynolds number of approximately 105. The researchers employed Computational Fluid Dynamics for the simulation with varying amplitudes, mean angles of oscillation, and frequencies in a two-set oscillating system. Dimchev (2012) conducted another study on the propellers mounted with wingtip with a UAV design and low aspect ratio. The study was conducted under a wind velocity ranging from 15 and 35 m/s and a 20 degrees proper blade angle. The results indicated that for a 10 degrees angle of attack, the there was an increase in the lift coefficient Cl from 0.34 to 0.46. On the contrary, there was a decrease of the drag coefficient Cd from -0.013 to -0.14. The figure below shows the flow profile of the drag and lift. Krogstad and Lund (2011) carried out a numerical and experimental analysis of a model turbine performance using a diameter of 90 cm for the model. The researchers used a S826 airfoil profile and used a Blade Element Theory to lay down the geometry. They then experimentally tested their design model and estimated the tip ratio at 6 and a peak power coefficient Cp at 0.448. A turbulence model known as - was used to undertake numerical calculations by applying a Computational Fluid Dynamics 3D simulation model. Evaluation and analysis of the findings From the literature analysis, it can be seen that the numerical and experimental results of the drug and lift of an airfoil vary depending on so many parameters. For instance, the experiments conducted under open tunnel as in the case of NACA 0015 reflect different values of the lift and drug constants. In addition, the area of cross section of the wind tunnel plays an imperative role in the value of the lift and drug coefficient obtained in an experimental setup. The other parameters that determine the value of the lift and drug coefficient include the velocity of the wind. Better results were obtained within the range of 20 and 30 m/s as the optimum wind speed. Moreover, the values obtained from the experiments indicate that an ideal attack angle averages at 16 degrees. The best experimental results obtained for the drag and lift coefficients vary between 0.15 and 0.75 respectively. In addition, the optimal Cl/Cd ratio that was recorded from the experiments is 8 degrees. The studies conducted by Tang, Zhang, Peng, and Liu (2012) suggest that airfoil develops a high lift at minimum forward velocities and demonstrates an exceptional potential for both the scenarios of upward takeoff and landing and that of fast takeoff and landing. As seen in most of the experiments, the pitching moment and lift constants of the airfoil rise and the resultant drag coefficient declines as the airfoil fan revolutionary velocity decreases. In aerodynamics, the pitching moment constant improvement shows that the aircraft achieves greater stability at elevated rotational velocities. Lombardi, Salvetti, and Pinelli, (2000) further highlight that experiments demonstrate that the streamline coefficients decline as the Reynolds number declines free stream. Besides, the flow area over the airfoil can best be been examined using the computational fluid dynamics approach and then comparing the results with the investigational results obtained. In most cases, the numerical results are in congruence with the values obtained in the experiments. Yu (2012) further establish that the rotational velocity of the airfoil does not affect the coefficient of skin resistance on the bottom wall of the airfoil. However, the upper surface of the foil, particularly the interior of the casing is greatly affected by the fan velocity. This also shows a rise in the Reynolds number on the two surfaces of the airfoil. Manolesos and Voutsinas (2016) cite that a close examination of the numerical method demonstrates that the difference between the inert pressure of the two airfoil surfaces lead to an increase in the rotational velocity. This leads to greater lift coefficients at a higher fan velocity, and a corresponding increase in the Reynolds number that corresponds to the improvement of the aeromechanic forces. Owing to the sharp edge of the airfoil, there occurs a dramatic abrupt jump in the pressure circulation on the upper region of the airfoil profile. When the sharp rim of the profile is replaced with a round and smooth profile, the pre ssure jump declines greatly and the resultant pressure distribution on the improved surface smoothens with a diminished extreme value (Norwazan, Khalid, Zulkiffli, Nadia, Fuad, 2012). The streamlines observed on the upper surface of the airfoil occurs at close proximity than the ones observed at the bottom of the airfoil. This indicates a greater pressure on the airfoils lower wall. The streamlines develops closeness on the upper area of the airfoil with an increase in the fan velocity. Additionally, the airfoil surface velocity gradient increases with increasing Reynolds number due to an elevated skin friction coefficient. Gao, Cai, Li, Jiang, and Lee (2016) and Ouchene, Khalij, Tanire, and Arcen (2015) cite that the incongruity that occurs between the experimental and numerical values are due to uncertainty in the experimental measurements and the convergence exactitude that occurs in the numerical approach. Furthermore, there is the reality of the 3D dimensional profile of the f low that is different from the theoretical 2D solution in the computational fluid dynamics (Haryanto, Utomo, Sinaga, Rosalia, Putra, 2014). Conclusion From the experiments and numerical analyses carried out, several factors determine the value of the lift and drag coefficients obtained. As observed in the paper, airfoil develops a great lift at minimum frontward velocities and evidences an outstanding potential for both the backdrops of vertical landing and takeoff and that of fast landing and takeoff. Also, as observed in the experimental results, the pitching moment and lift constants of the airfoil elevates and the consequential drag coefficient downslopes as the revolutionary velocity of the airfoil fan diminishes. In aeromechanics, the pitching moment constant improvement reflects that the aircraft attains a relatively better stability at superior rotational velocities. Additionally, experiments reflect that the streamline coefficients decay as the Reynolds number reduces for the free stream. Moreover, the field of flow above the airfoil can most excellently be observed using the computational fluid dynamics method and then dr awing parallels of the results with the experimental values realized. In most scenarios, the numerical data corresponds with the values achieved by undertaking the experiments. Reference List Askari, S. Shojaeefard, M., 2012. Experimental and numerical study of an airfoil in combination with a cross flow fan.Proceedings Of The Institution Of Mechanical Engineers, Part G: Journal Of Aerospace Engineering,227(7), 1173-1187. https://dx.doi.org/10.1177/0954410012452213 Bhat, S. Govardhan, R., 2013.Stall flutter of NACA 0012 airfoil at low Reynolds numbers.Dx.doi.org. Retrieved 2 September 2016, from https://dx.doi.org/10.1016/j.jfluidstructs.2013.04.001 Dedeic, A., 2014.Experimental and numerical study on harmonically pitching airfoils with morphing trailing edge flaps(Masters). Technical University of Denmark. Dimchev, M., 2012.Experimental and numerical study on wingtip mounted propellers for low aspect ratio UAV design(Masters). Delft University of Technology. Gao, Z., Cai, J., Li, J., Jiang, C., Lee, C., 2016. Numerical Study on Mechanism of Drag Reduction by Microblowing Technique on Supercritical Airfoil.J. Aerosp. Eng., 04016084. https://dx.doi.org/10.1061/(asce)as.1943-5525.0000685 Haryanto, I., Utomo, T., Sinaga, N., Rosalia, C., Putra, A., 2014. Optimization of Maximum Lift to Drag Ratio on Airfoil Design Based on Artificial Neural Network Utilizing Genetic Algorithm.AMM,493, 123-128. https://dx.doi.org/10.4028/www.scientific.net/amm.493.123 Krogstad, P. Lund, J., 2011. An experimental and numerical study of the performance of a model turbine.Wind Energ.,15(3), 443-457. https://dx.doi.org/10.1002/we.482 Lombardi, G., Salvetti, M., Pinelli, D., 2000. Numerical Evaluation of Airfoil Friction Drag.Journal Of Aircraft,37(2), 354-356. https://dx.doi.org/10.2514/2.2605 Manolesos, M. Voutsinas, S., 2016. Experimental Study of Drag-Reduction Devices on a Flatback Airfoil.AIAA Journal, 1-15. https://dx.doi.org/10.2514/1.j054901 Moreau, E., Jolibois, J., Benard, N., 2009.Lift and drag performances of an axisymmetric airfoil controlled by plasma actuator.Dx.doi.org. Retrieved 2 September 2016, from https://dx.doi.org/10.1016/j.elstat.2009.01.008 Norwazan, A., Khalid, A., Zulkiffli, A., Nadia, O., Fuad, M., 2012. Experimental and Numerical Analysis of Lift and Drag Force of Sedan Car Spoiler.AMM,165, 43-47. https://dx.doi.org/10.4028/www.scientific.net/amm.165.43 Ouchene, R., Khalij, M., Tanire, A., Arcen, B., 2015. Drag, lift and torque coefficients for ellipsoidal particles: From low to moderate particle Reynolds numbers.Computers Fluids,113, 53-64. https://dx.doi.org/10.1016/j.compfluid.2014.12.005 Ã… ¾ahin, . Acir, A., 2015. Numerical and Experimental Investigations of Lift and Drag Performances of NACA 0015 Wind Turbine Airfoil.International Journal Of Materials, Mechanics And Manufacturing,3(1), 22-25. https://dx.doi.org/10.7763/ijmmm.2015.v3.159 Tang, X., Zhang, X., Peng, R., Liu, X., 2012. Wind Tunnel Experimental Study of Wind Turbine Airfoil Aerodynamic Characteristics.AMM,260-261, 125-129. https://dx.doi.org/10.4028/www.scientific.net/amm.260-261.125 Wang, S., Ingham, D., Ma, L., Pourkashanian, M., Tao, Z., 2010.Numerical investigations on dynamic stall of low Reynolds number flow around oscillating airfoils.Dx.doi.org. Retrieved 2 September 2016, from https://dx.doi.org/10.1016/j.compfluid.2010.05.004 Yu, M., 2012.Numerical and experimental investigations on unsteady aerodynamics of flapping wing (Ph.D). Iowa State University.

Review of the methods to enhance efficiencies of solar pvcs Essay Example

Review of the methods to enhance efficiencies of solar pvcs Essay These are the questions that one individual should ask himself if he/she does an research on these organic solar cells. The reason behind their entry is the scarcity of existing crystalline solar cell manufacturing base material, day by day hiking cost. As we all know that the polymers and simple molecules are abundant on earths surface and are cheaper in cost, and having desirable physical properties like light weight, flexibility etc. These are initial parameters those pushed the researchers to step in and take the motive of introducing organic solar cells into semiconductor device industry. Initially silicon based solar cells were in many, but because of cost factor and their respective material properties they were moderately replaced by organic photo voltaic cells. As they are cheap, lightweight and are easy to fabricate they are in lead to crystalline organic photo voltaic cells. Devices made of these are supposed to have a theoretical efficiency of 10%. But, today, the efficiency we have for a small molecule organic photo voltaic cell is in the range of (0. 3-1. 3)%. Hence, efforts for higher efficiencies are under research for many years, and these researchers have even a point to notice that the designing and synthesis of donor acceptor materials is vital for an efficient organic photo voltaic cell. Challenges so far we have are because of their low efficiency, low strength, low stability, and sensitiveness to environment. Factors like band gap, charge carrier density, absorption coefficient for incident solar spectrum in visible and near IR range are important to improve the efficiencies. We will write a custom essay sample on Review of the methods to enhance efficiencies of solar pvcs specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Review of the methods to enhance efficiencies of solar pvcs specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Review of the methods to enhance efficiencies of solar pvcs specifically for you FOR ONLY $16.38 $13.9/page Hire Writer In this report we mainly focus on the organic solar cells based on small molecules. Having said that, we should know, why small molecules? The reason behind that is these small molecules has mostly hydrocarbons with carbon atoms alternatively linked to neighbor carbon atoms with alternate single-double bonding resulting into conjugated systems. In these systems the electrons in the p-z orbitals idealizes to form a idealized bond with orbital and anti-bonding with orbital. Where the orbital is considered as highest occupying molecular orbital (HOMO) and is least occupying molecular orbital(LOOM). Hence the gap between these two is considered to be the band-gap. Hence in small molecules the band-gap angels from 1-4 eve, which is moderately favorable for making a photo voltaic cell. When these systems absorb a photon, exited state is created in which e?ho pair is formed and is found to be bounded by electrostatic interaction. Hence, these conjugated systems are very vital to be maintained inside each small molecule. Slightly introducing the type of materials required. We first of all concerned about the properties like band-gap, high temperature resistant, thickness, charge carrier density, ease of fabrication, and stability. For a material, to be a desired one, it should have moderate band-gap I. . In the semiconductor range with high charge carrier density, high strength and resistance at high temperatures, long life of functioning, moderate if possible low thickness, high absorption cross-section to incident solar spectrum and ease to process and fabricate. As a part of our discussion in this term paper we will see what type of materials are necessary and how they function under applied light and generated electric field. For a small molecule based organic photo voltaic cell we generally choose indium oxide as electrode-I and metals with low work functions electrode-2. Generally we use Aluminum, Magnesium or Calcium. The difference between work functions between two electrodes develops electric field in organic layer. When light is incident on these elements sextons are produced as electrons are exited to LOOM leaving behind holes in HOMO. Potential difference due to difference in work functions separates the electron-hole pair inside the organic layer and pulls them as electrons to positive electrode and holes to the negative electrode. Here, the positive electrode is an electrical conductor used to make contact with a non-metallic part of circuit. Most importantly, for high efficiencies we should have high charge carrier density inside organic layer and controlling the loss of energy as heat from the organic layer surface. Hence we adopt some efficiency improvement methods based on the properties and functioning nature of the materials. Below are some of the methods we have reviewed to improve the efficiencies of organic photo voltaic cell based on small molecules. They are as follows: Methods to improve the efficiencies of organic solar cells based on small molecules: For a PVC (Organic Photo Voltaic Cell) based on copper pathetically-CO introducing beatification between buckminsterfullerene and aluminum cathodes gives the improvement of efficiency up to ;4%. Improving stability and lifetime of layered structure. Minimized charge recombination loss in Poops. Minimizing water and oxygen induced degradation of small molecules in Poops. Improving the efficiency of solution processed small molecule Poops using thermal annealing. By combining two vacuum processed heterogeneous to optimize the absorption power of PVC and controlling the construction parameters thereby making them efficient. Using a unstructured sandwich processing. Controlling parameters like band gap and dissipation of energy in the form of heat. By making molecules face to face by maintaining optimum donor acceptor relative positions. By energy harvesting and improved storage methods. Solution processing of small molecules to improve efficiency by 6. %. We will now further proceed into each method of improving efficiency in-detail. As we have noticed from above methods, we have adopted, most of them are having their vital role during processing of an PVC rather than it is being a product. Hence, in an semiconductor industry the manufacturing processes of elements is given prior rarity. For a PVC (Organic Photo Voltaic Cell) based on copper pathetical ly-CO gives the improvement of efficiency up to ;4% Most efforts are being made from past few decades to improve the efficiency of Poops. One among them is by inserting beatification(BCC) between fulfiller and aluminum cathode, organic thin film POP cells based on Chauncey-CO is observed to have an increased efficiency up to greater than 4%. Reason behind the insertion of this BCC layer is to minimize the exited loss during incident light and electric field. As the BCC inserted, obviously lays a very important roles in these cells by blocking the exited transport and hence named as Exited Blocking Layer. Once the exited transport is blocked, increases the charge carrier density inside the organic layer and minimizes the losses related to them and finally increasing the efficiency grater than 4%. Before the insertion of this BCC layer, the efficiency is around 1-1. 5%. Hence it is considered to be a good move in increasing the efficiency. But, a new problem has arises because of BCC insertion. The Poops lifetime was decreased; now the lifetime is about only few hours. This ay be probably due to the instability of inserted BCC layer, as it is easily crystallized in moist environment. BCC was already used for improving the electroluminescent efficiency in organic Leeds. However their lifetime is also found short because of instability of BCC layer. Hence for improving the stability we dope the BCC with PITCH (3,4,9,10-perpendicularitys-licks-biomedical) Improving stability and lifetime of layered structure. In this section a small molecule PVC with the structure of TIT I Donor electoral I buffer layer I III is studied as a case where we can improve efficiency to some extent. In this experiment the usage of Alas s a buffer layer instead of BCC is seen. Reason for using Alas instead of BCC is to use the effective blockage of waters lozenge to permeate through the acceptor layer. Another role of this new buffer layer is to block the diffusing cathode atoms into active layer during deposition and hence improve the efficiency. Describing the experiment, which is carried at room temperature without encapsulation, starting from deposition to the results in improved efficiency. Three types of buffer layers were used to study the I-V characteristics of the device in both light and dark. The layered structure of the PVC is shown below. As we can see the buffer layer is separating the cathode from CO. The three layers are For device. A with BCC as buffer layer, for device. B with 50% BCC+50% Alas, for device. C with pure Alas as buffer layer. In this experiment the power conversion efficiencies for all the three are measured under the illumination Oriel Solar Simulator producing an AM 1. 56 spectrum. The I-V characteristics are recorded by Keith 2400. The calibrated I-V characteristic is shown below. The experimental results from I-V characteristics ( Voce, Sis, IF) are tabulated below. Device Buffer Layer used Voce (V) Sis (ma/CM) Filling Factor(IF) Efficiency(%) A OHIOÂ ¼BCC. 42 5. 09 0. 49 1. 39 B 0. 49 5. 8 0. 464 1. 75 C 100% AlAlas. 506 6. 03 0. 52 2. 11 The irradiation intensity used is 75mawmCMf A. M 1. 5 simulated solar spectrum. Above values are same for the three devices under investigation. From the tabulated values it is clear that AlAlass most effective than BCBCCnd further experimental results have shown that the lifetime is increased up to 150 time the initial one. Hence by inserting an buffer layer which acts as blocking layer without affecting the life time of evvices also one of the good options of improving the efficiencies. Minimized charge recombination loss in OPPoopsIn this section we discuss about minimizing the recombination losses of CuCupTPatchhotovoltaic cell by employing spin forbidden transition to reduce the recombination loss in OPPoopsWithout the mixing processes like spin-orbit coupling, spin-lattice interaction and hyperfine coupling he spin conversion process between singlet and triplet is not possible. The molecular ground state have a singlet spin symmetry and hence the triplet CT states are forbidden to come and relax into the ground state. We an use this method to reduce the loss of recombination. The open circuit voltage and the fill factor can be improved by minimizing the recombination loss. Once VoVocend Fill factor are improved keeping IsSisonstant the efficiency improvement will take place. Minimizing water and oxygen induced degradation of small molecules in oppoopsThis section aims at complete knowledge of degradation of molecules because of water and oxygen during operation in small molecule based OPPoops Once material degradation takes place, its consequences affect the physical, mechanical and electrical properties of materials, and hence the efficiency of device. The most significant degradation mechanisms for organic solar cells is diffusion of molecular oxygen and water into the device. The organic solar cell we discuss in this section is of the composition ITTITnd A1AYre the two electrodes where ITTITehaves like anode and A1AYs like cathode. In this experiment we have three sets of samples with same coconfigurationThree types of environments are used in dark and light modes. Environments used are nitrogen, oxygen and water. The lifetime or end of lifetime of a solar cell is quoted as T88THr TSTTShich is the time taken by the device to reach 80% or 50% of its ininitialrreferenceWe use these values to record the lifetime of the above species in different environmental conditions. The results are tabulated below: Device name Intensity (W/m2mmTemperature (occoReReelHumidity(%) Atmosphere (1 atATMLife time( T88TH55THN2NOight 330 49 0 N2NO) 405/2700 N2NOark 0 26 0 N2NOlove box) 1802 Light 330 49 0-17AAA3/74 1802 Dark 0 48 0-17AAA H2H2O80 Light 330 39 65 H2H2O80:N2NO. /11 H2H2O80 Dark 048 65 H2H2O80:N2NO As we can see from the tabulated results, the life time is decreasing for water case than in oxygen case. Hence degradation is seen largely in case of water than in xyoxygenFollowing table will provide the knowledge of how the efficiency changes with different types of injection. Water injection showing the effect on Short circuit current, open circuit voltage , fill factor, and efficiency. As we can see from above data that the efficiency after injection is gradually decreasing. From the above data it is clear that the efficiency dropping Just after the oxygen injection is not as bad as water injection. Hence a moist free environment during preparing a layered structure, will play a vital role in improving the efficiencies of cells. Improving the efficiency of solution rorecessedmall molecule OPPoopssing thermal annealing. In this section we discuss about the insertion of (beFontainebleauBTBETunction into a ollighthousesackbones should lead to some interesting features for the photovoltaic applications. In addition, to enhance the light absorption properties by thermal annealing of active layers, and increase the hole mobility by inducing the self-organization of conjugated polymers or small molecules thereby increasing the efficiency of OPPoopsAll experimental conditions were carried under argon atmosphere with the use of standard scschlepsechniques. After being made the cell is having an effective area of 4mmomThe thermal annealing is carried out by directly placing the completed devices directly on a digitally controlled hotplate at various temperatures in a argon filled glove-box. The I-V characteristic curves of the photovoltaic cells are obtained by keKeith400 source measure unit. Results of the experiment with improved efficiencies is tabulated below: As we can see from the above three the normalized absorption region is high in particular range of wavelength. We can clearly see the LULUMPnd HOMO with their respective reduction and oxidation potential values. Following table gives the knowledge of effect of annealing on efficiency for different types of devices under different conditions. Hence annealing a device at appropriate temperature and under appropriate conditions will change the PCPACEfEfficiencyup to a significant extent. By combining two vacuum processed hetero Junctions to optimize the absorption power of OPPVCnd controlling the construction parameters thereby making them efficient. In this part of discussion, we have the concept of combining two vacuum processed single hetero junction organic solar cell with complementary absorption are described. The red bsabsorbingetero Junction consists of C6COnd a fluorinated zinc ptpathologicallyF4IFZnZinc thThateads to 0. 1-0. V open circuit voltage than the commonly used ZnZincFrom the manufacturing point of view, tandem concepts offer an advantage, due to serial connection of sub-cells the efficiency is increased by adding up voltages rather than currents. To increase the efficiency, we have to increase the absorption cross-section of the OPPVCFor absorption at longer wavelengths the fluorinated ptpatheticallyeriv ative (F4IFnZincis used as donor instead of ZnZincAs F4IFnZincs efficient in lowering the ionominationotential from 5. 1 eVveto. 46 eVeveue to the electron withdrawing character of the fluorine atoms. Higher fluorinated ptpathologicallytoms can be used as acceptors in organic solar cells. The absorption features of F4IFnZincn mixed layers with C6COre comparable to ZnZincexhibiting strong ababsorbencyn the red part of the spectrum peaking at 630 nmNMnd extending to above 800 nmNMThis is a good quality which is desired, as it increases the absorption coefficient of organic photovoltaic surface and thus increasing the efficiency. Heating the above mixed layer has the same effect that of common one but leads to an improvement in charge arairierensity. This can be seen through the mismatch of I-V characteristics. Hence here above we found out two more concepts of increasing the efficiencies. Now we further look into the dependence of efficiency on factors like light intensity, angle of illumination and temperature. For a OPPVCith a given efficiency, thickness and incident wavelength the most important factors on which we should concern about are the performance of the device under different illumination intensities for varying illumination angles at typical operating temperatures. 343429000449580Fromig. : The nfinfluencef illumination intensity on the device performance from 0. 5mMomcmCMo 310 mWmmmCMThe illumination is provided by halogen lamp kept at constant temperature of 25ICCheHereJsSCs directly proportional to lint over the complete range of illumination intensities. VoVoces increasing continuously with lint but below logarithmic value. FFIFhows weak maximum at lint?70mawmCMfter which it decreases by approximately 4% up to 31mawmCMThis shows the maximum power point to be mostly sub-line ar and the maximum efficiency approximately at 40mawcmCMFrom fig. : The influence of illumination intensity on the device performance roroom. 5mMomcmCMo 310 mWmmmCMThe illumination is provided by halogen lamp kept at constant temperature of 25ICCheHereJsSCs directly proportional to lint over the complete range of illumination intensities. VoVoces increasing continuously with lint but below logarithmic value. FFIFhows weak maximum at lint?70mawmCMfter which it decreases by approximately 4% up to 31mawmCMThis shows the maximum power cmCMGiven below is the calibrated data showing the dependence of illumination intensity on the device performance:leleptonsing a naunstructuredandwich processing. In this section we will see the structural dependence of OPPVCevice layers on efficiency. Researchers found that the efficiency of a device is almost tripled when naunstructuredandwich metal and plastic are used. These type of structures can collects and traps the light more effectively than any other. The nanotechnology is used to overcome the challenges that cause solar cells to lose energy. Challenges like light reflecting from the layered surface and inability of the cell to capture the light fully that enters in. But with the help of this NaAnnaaterial sandwich we can answer both the problems. The sandwich, which is generally called as sub-wavelength plplatonicavity. Have extraordinary characteristics of damping reflection and trapping light. Using this technique research studies have show us that only approximately 4% of the light is reflected and as much as 96% of the light is absorbed accounted for the increase in efficiency up to 52%. Above description is only for the direct sunlight(perpendicular light falling normal to the surface). This efficiency is much more for a solar cell surface upon which the light incident is at large angles i.Ie.EonOnloudy days and when cells not facing the light directly/ erreproductivelyBy capturing these light incident at large angles one can boost up the efficiency up to extra 81%, combining a total of 175% increase in efficiency. Thought the physics behind the innovation is complex the device structure is simple. The window layer(top layer) is extremely fine metal mesh and of the size of 30NMhick with each mesh having diameter of 17Mannnd 25NMpart. This mesh layer can even replace the ITTITayer. A picture of such naAnnaesh layer is shown below: The mesh window layer is placed very close to the bottom layer of the sandwich, the same metal film used in conventional solar cells. In between the two metal sheets is a thin strip of sesemiconductoraterial used in solar panels. It can be any type silicon, plastic or gallium arsenide although ChCohoseam used an 85-nanometer- thick plastic. The solar cells features the spacing of the mesh, the thickness of the sandwich, the diameter of the holes are all smaller than the wavelength of the light being collected. This is critical because light behaves in very unusual ways in sub- wavelength structures. ChCohoseam discovered that using these sub-wavelength structures allowed them to create a trap in which light enters, with almost no effleetingand does not leave, and hence efficiency is drastically can be increased. Here we will see some of the common factors like band gap of semiconductor, electric charge recombination and energy dissipation in the form of heat, which are limiting factors for power conversion efficiency of a solar cell. Light with less than the enenergyf band gap cannot be absorbed and cannot generate electricity inside the organic layer. Let say that the light with higher intensity and higher than the band gap is incident and generated the electricity inside the device and lets say that the charges aveaveeen generated. These generated charges if lost because of recombination; the electric current inside the device will decrease: and so the electric power of the cell will decrease. The relation between the maximum conversion efficiency and optical absorption edge are given in the following pipickHere: The red line represents the conventional theoretical limit of single-junction- inorganic cell; blue line represents the theoretical limit of the single-junction-organic solar cell; the black line represents the theoretical limit of the multi-]unction-organic cell. The theoretically calculated photoelectric conversion efficiency for a single junction- organic photovoltaic cell is about 21%. From the above picture we can see that for an appropriate range of optical absorption edge value only the maximum efficiency can be attained. Right side of pipicks the rough sketch of layered structure. Where, two active organic layers separate both the electrodes. By making molecules face to face by maintaining optimum donor acceptor relative positions. In this section we further precede our methods of improving the efficiency in organic solar cells aseasedn small molecules, and their dependence in structure at molecular levels. Researchers have shown that to transfer maximum energy more effectively inside of complex three dimensional OPPoopss to align the donor molecules face-on, rather than relative to acceptor or edge-on to the acceptors. We know that exexitedn energy particle created when light is incident on the material and got absorbed. This efficiency of a cell depends on this exexitedThis exexiteds found at the donor acceptor interface inside the cell. At interface exexitedreates power by itself converting into haharearriers that travel to the electrodes. Meanwhile inside at molecular level the atoms inside the donor acceptor levels itself mixes, cluster or both leading to the variances inside the domain leading to affect the conversion process and thereby affecting the efficiency. It is difficult for an individual to consider all changes at a time. 2525146001249680Buthen we consider the face-on orientation, which allows the favorable interactions for charge transfer and lessen the recombination loss can be thought of when efficiency is considered. The sample picture of face-on orientation eaeatingo favorable charge interactions is seen in the picture beside. OBBouthen we consider the face-on orientation, which allows the favorable interactions for charge transfer and lessen the recombination loss can be thought of when efficiency is considered. The sample picture of face-on orientation leading to favorable charge interactions is seen in the picture beside. By energy harvesting and improved storage methods. Most significant problem now a day to an organic photovoltaic industry facing is loss of energy. Saving, storing the dissipated energy will improve the efficiency more than nyNYther methods we adopted so far. Most of the dissipated energy is in the form of heat. Loss of energy is because of organic materials lack in properties to hold them up. Energy harvesting is a process by which ambient neenergys captured and converted into electricity. These energy harvesting includes ththermostaticphotovoltaic, piezoelectric materials. More the harvesting and storage material is efficient, more the efficiency of the solar cell. Solution processing of small molecules to improve efficiency by 6. 7% In this section we see that the solution processed small molecule organic solar cells an perform up to efficiencies ranging 6-8%. A combination of polymer design, morphology control, structural insight and device engineering lead us this much of efficiency. However solution processed small molecule BHBBCave their efficiencies below the polymeric ones. 33147005715 Normalized ababsorptionsvs.waWavelengthan be seen from adjacent fgfigures a result of solution processing. Normalized ababsorptionsvs.waWavelengthan be seen from adjacent figure as a result of solution processing. The component DIDIDs added to the solution to enhance the efficiency improving properties. We have a range of 0-1% v/v vixing.