Physics Assignment代写:光伏电池
Keywords:Physics Assignment代写
光伏电池的效率取决于设备的能量转换和收费，这是高无机基光伏器件，但是有机光伏器件在无机光伏器件即大优势低成本制造，机械的灵活性和通用性。这导致许多研究集中在聚合物太阳能电池，因此已经提出了几种方法用于制造光伏电池像单双层利用光致导电聚合物作为供体材料的电子转移的有机太阳能电池（D）和富勒烯及其衍生物的作用（一）。然而，转换效率是有限的载流子收集效率的D-A界面。在有机太阳能电池领域的一个重大突破是通过克服双层异质结的效率的限制，提出的聚合物。一个高的界面面积达到了散装物料通过仔细控制相分离的形态为互穿网络连续模，产生高效的光诱导电荷分离，这得到的界面区域被称为“散装D-A异质结”。尽管本体异质结是先前由Hiramoto等人提出的，[ J. Appl。Phys。72，3781，1992 ]而太阳电池的制备方法比黑格更加困难。 黑格用复合膜（聚甲氧基-5-（2-乙基-己氧基）- 1 -对苯乙炔）（MEH-PPV）和可溶性衍生物[6,6]-富勒烯即PCBM和[5,6] PCBM形成聚合物共混物。为了克服C60的溶解度有限，一系列水溶性C60衍生物的使用，这种可溶性C60衍生物的概念能够实现新装置的概念。体异质结的结构由不同工作函数的金属电极触点（Ca或Al）来优化空穴的载流子收集的效率，从施主相和电子从受主相。 铟锡氧化物（ITO）作为阳极，Ca或铝作为阳极自动提取电子和空穴的聚合物共混物。体异质结光伏电池的性能取决于聚合物共混器件中的相分离，所以大部分的研究都集中在相分离的精确控制上。的膜的形成必须是非常快的，以获得精细的结构，即，相分离必须被逮捕较早，这会导致更小的域比激子扩散长度。这可以实现[广告材料。12，498，2000 ]通过旋涂在加热的基板上，使溶剂蒸发更快。
Physics Assignment代写:光伏电池
Efficiency of Photovoltaic cells depends on the energy conversion and charge collection of the device, which are high in inorganic based photovoltaic device, however organic photovoltaic devices have major advantages over inorganic photovoltaic devices i.e., low-cost fabrication, mechanical flexibility and disposability. This led many researches to focus on polymer photovoltaic cells, hence several approaches have been proposed for fabricating photovoltaic cells like mono and bilayered organic solar cells by using photo induced electron transfer in composites of conducting polymers as donors(D) and Buckminsterfullerene and its derivatives as acceptors(A). However the conversion efficiency is limited by the carrier collection efficiency at the D-A interface. A major breakthrough in the field of organic photovoltaic cells is achieved by overcoming the limitation of the efficiency in the bilayer heterojunction, which is proposed by Heeger. A high interfacial area is achieved within a bulk material by carefully controlling the morphology of the phase separation into an interpenetrating bicontinuous D-A network, which yields efficient photo induced charge separation, this obtained interfacial area is known as "Bulk D-A heterojunction". Even though the bulk heterojunction is previously proposed by Hiramoto et al, [J. Appl. Phys. 72, 3781, 1992] but the fabrication of solar cells is far more difficult than that of Heeger approach.Heeger used composite film of poly (2-methoxy-5-(2-ethyl-hexyloxy)-1, 4-phenylene vinylene) (MEH-PPV) and soluble derivatives of buckminsterfullerene namely [6,6]PCBM and [5,6]PCBM to form a polymer blend. To overcome the limited solubility of C60, a series of soluble C60 derivatives are used, this concept of soluble C60 derivatives enabled to realize new device concept. The structure of bulk heterojunction consists of metal electrode contacts (Ca or Al) of different work function to optimise the efficiency of carrier collection of holes from donor phase and electrons from acceptor phase.Indium tin oxide (ITO) is used as anode and Ca or Al is used as anode which automatically extracts electrons and holes from the polymer blend. The performance of bulk heterojunction photovoltaic cells depends on the phase separation in polymer blend devices; so much of the research is concentrated on the precise control of the phase separation. The film formation has to be very fast, in order to obtain fine structures i.e., Phase separation has to be arrested earlier, which results in smaller domains than exciton diffusion length. This can be achieved [Adv. Mater. 12, 498, 2000] by spin coating on a heated substrate, so that the solvent evaporates faster.
