Polyfluorenes solar cells

M Svensson, F Zhang, SC Veenstra, WJH Verhees, JC Hummelen, JM Kroon, O Inganas, and MR Andersson, High-performance polymer solar cells of an alternating polyfluorene copolymer and a fullerene derivative, Adv. Mater., 15 988-991, 2003. 

Fluorene oligomers have seen only limited use in organic solar cells to date. If they incorporate any fluorene units at all, most efforts have focused on polyfluorene derivatives [19,20]. For example, Bryce et al. synthesized a series of oligofluorene-fullerene derivatives to study their fundamental photophysical and charge transfer properties [216] (compounds 62-67 in Fig. 17), but have not pursued such structures for organic solar cells yet. 

A major deviation from the above picture was found by Ramsdale et al., who investigated bilayer solar cells based on two polyfluorene derivatives [125]. When compared to the work function of both electrodes, the authors measured a Voc exceeding those values by about 1 eV. This overpotential has been accounted for by a concentration driven diffusion current. 

Yohannes T, Zhang F, Svensson M, Hummelen JC, Andersson MR, Ingantls O (2004) Polyfluorene copolymer based bulk heterojunction solar cells. Thin Solid Films 449 152... 

Wang X, Perzon E, Delgado JL, de la Cruz P, Zhang F, Langa F, Andersson M, Inganas O (2004) Infrared photocurrent spectral response from plastic solar cell with low-bandgap polyfluorene and fullerene derivative. Appl Phys Lett 85 5081... 

Wang X, Perzon E, Oswald F, Langa F, Admassie S, Andersson MR, Inganas O (2005) Enhanced photocurrent spectral response in low-bandgap polyfluorene and C70-derivative-based solar cells. Adv Funct Mater 15 1665... 

K.G. Jespersen, F.L. Zhang, A. Gadisa, V. Sundstrom, A. Yartsev, and O. Inganas, Charge formation and transport in bulk-heterojunction solar cells based on alternating polyfluorene copolymers blended with fuUerenes, Org. Electr., 7, 235-242 (2006). 

M.-H. Chen, J. Hou, Z. Hong, G. Yang, S. Sista, L.-M. Chen, Y. Yang, Efficient Polymer Solar Cells with Thin Active Layers Based on Alternating Polyfluorene Copolymer/Fullerene Bulk Heterojunctions. Adv. Mater. 2009, 21,4238-4242. 

Andersson and coworkers have prepared solar cells based on blends of poly(2,7-(9-(2 -ethylhexyl)-9-hexyl-fluorene)-fl/t-5,5-(4, 7 -di-2-thienyl-2, l, 3 -benzothiadiazole) (223) and PCBM [416]. The polymer shows a Amax (545 nm) with a broad optical absorption in the visible spectrum and an efficiency of 2.2% has been measured under simulated solar light. The same group has also reported the synthesis of low bandgap polymers 200 (1 = 1.25 eV) and 224 (1 = 1.46 eV) which have been blended with a soluble pyrazolino[70]fiillerene and PCBM, respectively, to form bulk heterojunction solar cells of PCE of 0.7% [417] and 0.9% [418]. Incorporation of an electron-delident silole moiety in a polyfluorene chain affords an alternating conjugated copolymer (225) with an optical bandgap of 2.08 eV. A solar cell based on a mixture 1 4 of 225 and PCBM exhibits 2.01% of PCE [419]. 

Zhang, F.L. etal, (2006) Influence of solvent mixing on the morphology and performance of solar cells based on polyfluorene copolymer/flillerene blends. Adv. Funct. Mater., 16 (5),... 

LIU 08] Liu X., Zhu R., Zhang Y. et al., Anionic benzothiadiazole containing polyfluorene and oligofluorene as organic sensitizers for dye-sensitized solar cells . Chemical Communications, vol. 32, pp. 3789-3791, 2008. 

Svensson M, Zhang F, Veenstra SC, Verhees WJH, Hummelen JC, Kroon JM, Inganas O, Andersson MR (2003) High-ptaformance polymer solar cells of an alternating polyfluorene copolymer and a fnllerene derivative. Adv Mater 15 988... 

Salim T, Sun S, Wong LH, Xi L, Foo YL, Lam YM. The role of poly(3-hexylthiophene) nanofibers in an all-polymer blend with a polyfluorene copolymer for solar cell applications. J Phy s ChemC 2010 114(20) 9459-9468. 

Film structures with domains that form elements with complementary functions of (a) solar cells, obtained using electron-donating polyfluorene copolymer APFO-3 and electron-accepting fullerene derivative PCBM and (b) of electronic circuitries using conjugated poly(3-alkylthiophene) P3AT and dielectric polystyrene PS. 

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