Conjugated regioregular poly[3-(5-carboxypentyl) thiophene-2,5-diyl] (P3CPenT), a derivative of poly(3-hexylthiophene) (P3HT), is introduced as a hole transport layer (HTL) for P3HT:PCBM plastic solar cells (PSCs). P3CPenT, a carboxyl-functionalized polythiophene, is insoluble in solvents typically used in the preparation of photoactive layers such as chloroform, chlorobenzene and dichlorobenzene, allowing successive processing of the photoactive layer without dissolution of the HTL. P3CPenT self-assembles into nanowires in DMSO solution and when cast as a film, reduces concentration gradients of P3HT:PCBM photoactive layers. P3HT:PCBM PSCs incorporating P3CPenT nanowires as the HTL have a higher fill factor (FF, 0.67) and power conversion efficiency (PCE, 3.7%) than devices with conventional PEDOT:PSS HTLs. 2012 The Royal Society of Chemistry.
Li, W., J.B. Worfolk, P. Li, T.C. Hauger, K.D. Harris, J.M. Buriak
Journal of Materials Chemistry
11354 - 11363