Photovoltaic device polymer solar cell

Polymer solar-cell devices based on a blend of poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester, and incorporating doped PANI-NTs as an interfacial layer, have been fabricated [511,512]. The power-conversion efficiency of an annealed device incorporating the PANI-NTs layer showed an increase of 26% relative to that of the annealed device lacking the PANI-NTs interfacial layer. The high conductivity, controlled tubular nanoscale morphologies, and mobility of the annealed PANI-NTs layer led to efficient extraction of photogenerated holes to the buffer layer and suppression of exciton recombination, thereby improving the photovoltaic performance. 

Currently the best-performing heterojunction photovoltaic devices are made from blends of polythiophenes and PCBM [6,106]. Here, the charge-transfer states are stable with respect to triplet excitons, which comes at the cost of modest open-circuit voltages of 0.6V. Recent experimental evidence suggests that the high performance of PCBM polymer solar cells could also be attributed to the kinetic advantage in charge-transfer state separation that these cells have over those made from amorphous polymers. It is... 

At the early development of polymer solar cells, a planar p-n junction structure represented the mainstream in mimicking conventional silicon-based solar cells. However, the obtained devices demonstrated poor photovoltaic performances due to the long distance between the exciton and junction interface and insufficient light absorption due to the thin light absorber. It was not until 1995 that the dilemma was overcome with the discovery of a novel bulk heterojunction in which donor and acceptor form interpenetrated phases. Poly[2-methoxy-5-(2 -ethylhexyloxy)-p-phenylene vinylene] was blended with Ceo or its derivatives to form the bulk heterojunction. A much improved power conversion efficiency of 2.9% was thus achieved under the illumination of 20 mW/cm. (Yu et al., 1995). The emergence of the donor/acceptor bulk-heterojunction structure had boosted the photovoltaic performances of polymer solar cells. Currently, a maximal power conversion efficiency of 10.6% had been reported on the basis of synthesizing appropriate polymer materials and designing a tandem structure (You et al., 2013). The detailed discussions are provided in Chapter 5. 

Many authors have reported different approaches for incorporation of different metallic NPs in organic solar cells (OSCs) i.e. in the photoactive layer, in the hole transport layer (HTL), at the HTL/photoactive layer interface and at the ITO/HTL interface. Fig. 6 shows the schematic design describing these different approaches. We have reviewed the detail literature of photovoltaic performance parameters of bulk heterojunction organic/polymer solar cell. Table 1, 2, 3, 4 summarizes the state of the art reports i.e., open circuit voltage (Voc), short circuit current density (jsc), fill factor (FF) and power conversion efficiency (ti) of plasmonic enhanced OSC devices with NPs embedded between interfacing layers, NPs in the hole conducting layers, combination of different NPs and NPs in the photoactive layer, respectively. 

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