Premium
Working Principles of Perovskite Photodetectors: Analyzing the Interplay Between Photoconductivity and Voltage‐Driven Energy‐Level Alignment
Author(s) -
Domanski Konrad,
Tress Wolfgang,
Moehl Thomas,
Saliba Michael,
Nazeeruddin Mohammad Khaja,
Grätzel Michael
Publication year - 2015
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.201503188
Subject(s) - materials science , photocurrent , perovskite (structure) , responsivity , photodetector , optoelectronics , photoconductivity , photovoltaics , tin oxide , work function , doping , nanotechnology , photovoltaic system , chemical engineering , layer (electronics) , ecology , engineering , biology
Organic–inorganic lead halide perovskites have recently received significant attention as active materials for high‐performance photovoltaics and photodetectors. However, the understanding of their operation mechanism remains limited. High‐gain, low‐voltage CH 3 NH 3 PbI 3 photodetectors in various architectures are demonstrated herein. Photomultiplication in all structures with direct contact of fluorine‐doped tin oxide (FTO) and perovskite with the highest responsivity 208 A W −1 corresponding to an incident photon‐to‐current efficiency of 47 000% is observed. Studying the dynamics and temperature dependence, a slow process with an activation energy of 420 ± 90 meV in the time scale of seconds is found, which is essential to photocurrent multiplication. A model based on ion migration to explain the observed transients and the photomultiplication is developed. The accumulation of negative ionic charge at the FTO/perovskite interface under reverse bias lowers the FTO work function allowing for direct hole injection into the perovskite valence band. Under illumination, the conductivity of perovskite is increased and the device behaves similar to a photoconductor.