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Ultrasensitive Solution-Processed Broadband PbSe Photodetectors through Photomultiplication Effect

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journal contribution
posted on 05.02.2019, 00:00 by Tao Zhu, Luyao Zheng, Xiang Yao, Lei Liu, Fei Huang, Yong Cao, Xiong Gong
Broadband photodetectors have important applications in both scientific and industrial sectors. In this study, we report room-temperature-operated solution-processed photodetectors by PbSe quantum dots (QDs) with spectral response from 350 to 2500 nm. In order to boost both external quantum efficiency (EQE) and projected detectivity (D*), the hole-trap-assisted photomultiplication effect through the EDT-PbSe QD/TABI PbSe QD double-thin-layer thin film, where EDT-PbSe QDs are 1,2-ethanedithiol (EDT)-capped PbSe QDs and TABI-PbSe QDs are tetrabutylammonium (TABI)-capped PbSe QDs, is applied. To further enhance D*, a thin layer of the conjugated polyelectrolyte, which offers significant hole injection resistance for suppressing dark current but enhancing photocurrent under illumination due to the photoinduced self-doping process, is applied for reengineering the electron extraction layer in PbSe QD-based photodetectors. As a result, at room temperature, PbSe QD-based photodetectors exhibit over 450% EQE and over ∼1012 Jones D* in the visible region and over 120% EQE and D* ∼4 × 1011 Jones in the infrared region. These results demonstrate that our studies provide a simple approach to realize room-temperature-operated solution-processed broadband photodetectors.