Solution-processed pH-neutral conjugated polyelectrolyte improves interfacial contact in organic solar cells.

Zhou, Huiqiong; Zhang, Yuan; Mai, Cheng-Kang; Seifter, Jason; Nguyen, Thuc-Quyen; Bazan, Guillermo C; Heeger, Alan J · ACS Nano · 2015

basic_science · Level V

Where this comes from

Abstract

The intrinsic acidic nature of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole-transporting layer (HTL) induces interfacial protonation and limits the device performance in organic solar cells based on basic pyridylthiadiazole units. By utilizing a pH neutral, water/alcohol soluble conjugated polyelectrolyte CPE-K as the HTL in p-DTS(PTTh2)2:PC71BM solar cells, a 60% enhancement in PCE has been obtained with an increased V(bi), reduced R(s), and improved charge extraction. These effects originate from the elimination of interfacial protonation and energy barrier compared with the PEDOT:PSS HTL.