Bulk heterojunction polymer structure

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. 

Usually, the photoactive layer of bulk heterojunction solar cells is a physical blend [1-3] of a rr-conjugated polymer [12] and a fullerene derivative [13-17]. This bulk heterojunction structure inspired the design and preparation of donor... 

Figure 7.10 Tandem solar cell structure for polymer blend solar cells, based on the design demonstrated by Hadipour et al. (2006). In this all-solution-processed device, the top cell consists of a polymer PCBM bulk heterojunction with an absorption maximum of 550 nm and preferentially absorbs short-wavelength light, while the bottom cell is made from a bulk heterojunction of PCBM with a red-absortring polymer and absorbs longer-wavelength light. The composite gold-PEDOT PSS internal layer connects the two cells in...

Fig. 69 Ideal structure of a donor-acceptor bulk heterojunction polymer solar cell...

In this spirit, we will smdy the performance of structured PEDOT films in batteries and/or supercapacitors as well as the application of dedoped PT and P3MT in bulk heterojunction solar cells in the near future [12-15]. Furthermore, thenanostructured conjugated polymer films may find application in thermoelectric devices [47-50],... 

Street, R.A., Hawks, S.A., Khlyabich, P.P., Li, G., Schwartz, B.J., Thompson, B.C.,Yang,Y, 2014. Electronic structure and transition energies in polymer-fuUerene bulk heterojunctions. J. Phys. Chem. C 118, 21873-21883. 

Rathgeber S, Perlich J, KAhnlenz F, TArk S, Egbe DA, Hoppe H, et al. Correlation between polymer architecture, mesoscale structure and photovoltaic performance in side-chain-modified poly(p-arylene-ethynyl-ene)-alt-poly(p-arylene-vinylene) PCBM bulk-heterojunction solar cells. Polymer 2011 52(17) 3819-26. 

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