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Origin of Open‐Circuit Voltage Turnover in Organic Solar Cells at Low Temperature
Author(s) -
Tang Yahui,
Bjuggren Jonas M.,
Fei Zhuping,
Andersson Mats R.,
Heeney Martin,
McNeill Christopher Robert
Publication year - 2020
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.202000375
Subject(s) - organic solar cell , open circuit voltage , leakage (economics) , materials science , fullerene , acceptor , nanotechnology , polymer , voltage , atmospheric temperature range , optoelectronics , chemical physics , chemistry , electrical engineering , physics , condensed matter physics , thermodynamics , engineering , organic chemistry , economics , macroeconomics , composite material
While the efficiency of organic solar cells (OSCs) has increased considerably in recent years, there remains a significant gap between the experimental open‐circuit voltage ( V OC ) and the theoretical limit. Understanding the origin of this energy loss is important for the future development of OSCs, with temperature‐dependent measurement of V OC an important approach to help unlock the underlying physics. Interestingly, previous studies have observed a reduction in V OC at low temperature that has been attributed by different studies to different phenomena. To resolve this issue, herein the temperature dependence of V OC of various polymer‐based OSC systems covering a range of acceptor types (fullerene, polymer, and non‐fullerene small molecule) as well as device architectures (conventional, inverted, blend and bilayer) is studied. Across all systems studied, V OC reduction at low temperatures is associated with high parasitic leakage current, providing a universal explanation for this phenomenon in OSCs. Moreover, it is shown that leakage current, which causes complexity in the analysis and raises reliability concerns in potential applications, can be suppressed by varying device architecture, providing an effective approach for analyzing the true temperature dependence of V OC .