Premium
Harnessing Structure–Property Relationshipsfor Poly(alkyl thiophene)–Fullerene Derivative Thin Filmsto Optimize Performance in Photovoltaic Devices
Author(s) -
Deb Nabankur,
Li Bohao,
Skoda Maximilian,
Rogers Sarah,
Sun Yan,
Gong Xiong,
Karim Alamgir,
Sumpter Bobby G.,
Bucknall David G.
Publication year - 2016
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201502653
Subject(s) - materials science , fullerene , polymer solar cell , organic solar cell , active layer , thiophene , energy conversion efficiency , chemical engineering , x ray photoelectron spectroscopy , neutron reflectometry , photovoltaics , annealing (glass) , optoelectronics , polymer , photovoltaic system , nanotechnology , layer (electronics) , scattering , organic chemistry , neutron scattering , optics , composite material , small angle neutron scattering , chemistry , ecology , engineering , biology , physics , thin film transistor
Nanoscale bulk heterojunction (BHJ) systems, consisting of fullerenes dispersed in conjugated polymers have been actively studied in order to produce high performance organic photovoltaics. How the BHJ morphology affects device efficiency, is currently ill‐understood. Neutron reflection together with grazing incidence X‐ray and neutron scattering and X‐ray photoelectron spectroscopy are utilized to gain understanding of the BHJ morphology in functional devices. For nine model systems, based on mixtures of three poly(3‐alkyl thiophenes, P3AT) (A = butyl, hexyl, octyl) blended with three different fullerene derivatives, the BHJ morphology through the film thickness is determined. It is shown that fullerene enrichment occurs at both the electrode interfaces after annealing. The degree of fullerene enrichment is found to strongly correlate with the short circuit current ( J SC ) and to a lesser degree with the fill factor. Based on these findings, it is demonstrated that by deliberately adding a fullerene layer at the electron transport layer interface, J SC can be increased by up to 20%, resulting in an overall increase in power conversion efficiency of 5%.