Premium
Deep Energetic Trap States in Organic Photovoltaic Devices
Author(s) -
Shuttle Christopher G.,
Treat Neil D.,
Douglas Jessica D.,
Fréchet Jean M. J.,
Chabinyc Michael L.
Publication year - 2012
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201100541
Subject(s) - materials science , organic solar cell , photovoltaic system , photovoltaics , optoelectronics , organic semiconductor , acceptor , polymer solar cell , population , open circuit voltage , doping , fullerene , polymer , solar cell , chemical physics , voltage , condensed matter physics , chemistry , organic chemistry , electrical engineering , physics , demography , sociology , composite material , engineering
The nature of energetic disorder in organic semiconductors is poorly understood. In photovoltaics, energetic disorder leads to reductions in the open circuit voltage and contributes to other loss processes. In this work, three independent optoelectronic methods were used to determine the long‐lived carrier populations in a high efficiency N ‐alkylthieno[3,4‐ c ]pyrrole‐4,6‐dione (TPD) based polymer: fullerene solar cell. In the TPD co‐polymer, all methods indicate the presence of a long‐lived carrier population of ∼ 10 15 cm −3 on timescales ≥ 100 μs. Additionally, the behavior of these photovoltaic devices under optical bias is consistent with deep energetic lying trap states. Comparative measurements were also performed on high efficiency poly‐3‐hexylthiophene (P3HT): fullerene solar cells; however a similar long‐lived carrier population was not observed. This observation is consistent with a higher acceptor concentration (doping) in P3HT than in the TPD‐based copolymer.