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Broad-Band Photodetectors Based on Copper Indium Diselenide Quantum Dots in a Methylammonium Lead Iodide Perovskite Matrix
journal contribution
posted on 2020-07-23, 11:41 authored by Zonghui Duan, Jiajia Ning, Mengyu Chen, Yuan Xiong, Wenhong Yang, Fengping Xiao, Stephen V. Kershaw, Ni Zhao, Shumin Xiao, Andrey L. RogachLow-temperature solution-processed
methylammonium lead iodide (MAPbI3) crystalline films have
shown outstanding performance in
optoelectronic devices. However, their high dark current and high
noise equivalent power prevent their application in broad-band photodetectors.
Here, we applied a facile solution-based antisolvent strategy to fabricate
a hybrid structure of CuInSe2 quantum dots (CISe QDs) embedded
into a MAPbI3 matrix, which not only enhances the photodetector
responsivity, showing a large on/off ratio of 104 at 2
V bias compared with the bare perovskite films, but also significantly
(for over 7 days) improves the device stability, with hydrophobic
ligands on the CuInSe2 QDs acting as a barrier against
the uptake of environmental moisture. MAPbI3/CISe QD-based
lateral photodetectors exhibit high responsivities of >0.5 A/W
and
10.4 mA/W in the visible and near-infrared regions, respectively,
partly because of the formation of a type II interface between the
respective semiconductors but most significantly because of the efficient
trap-state passivation of the perovskite grain surfaces, and the reduction
in the twinning-induced trap density, which stems from both CISe QDs
and their organic ligands. A large specific detectivity of 2.2 ×
1012 Jones at 525 nm illumination (1 μW/cm2), a fast fall time of 236 μs, and an extremely low noise equivalent
power of 45 fW/Hz1/2 have been achieved.