title: Solution-grown organic single-crystalline donor-acceptor heterojunctions for photovoltaics.
abstract: Organic single crystals are ideal candidates for high-performance photovoltaics due to their high charge mobility and long exciton diffusion length; however, they have not been largely considered for photovoltaics due to the practical difficulty in making a heterojunction between donor and acceptor single crystals. Here, we demonstrate that extended single-crystalline heterojunctions with a consistent donor-top and acceptor-bottom structure throughout the substrate can be simply obtained from a mixed solution of C60 (acceptor) and 3,6-bis(5-(4-n-butylphenyl)thiophene-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4-dione (donor). 46 photovoltaic devices were studied with the power conversion efficiency of (0.255±0.095)% under 1 sun, which is significantly higher than the previously reported value for a vapor-grown organic single-crystalline donor-acceptor heterojunction (0.007%). As such, this work opens a practical avenue for the study of organic photovoltaics based on single crystals.
authors.affiliation: MOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027 (P.R. China). hanying_li@zju.edu.cn.
authors.forename: Hanying
authors.initials: H
authors.lastname: Li
authors.forename: Congcheng
authors.initials: C
authors.lastname: Fan
authors.forename: Weifei
authors.initials: W
authors.lastname: Fu
authors.forename: Huolin L
authors.initials: HL
authors.lastname: Xin
authors.forename: Hongzheng
authors.initials: H
authors.lastname: Chen
keywords: crystal growth; heterojunctions; organic field-effect transistors; organic photovoltaics; semiconductors