Department of Polymer Engineering, College of Polymer Science and Polymer Engineering , The University of Akron , Akron , Ohio 44325 , United States.
Institute of Molecular Plus , Tianjin University , Tianjin 300072 , P. R. China.
ACS Appl Mater Interfaces. 2019 Mar 6;11(9):9205-9212. doi: 10.1021/acsami.8b21966. Epub 2019 Feb 19.
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 ∼10 Jones D* in the visible region and over 120% EQE and D* ∼4 × 10 Jones in the infrared region. These results demonstrate that our studies provide a simple approach to realize room-temperature-operated solution-processed broadband photodetectors.
宽带光电探测器在科学和工业领域都有重要的应用。在这项研究中，我们报告了在室温下工作的溶液处理光电探测器，它使用的是 PbSe 量子点（QD），光谱响应范围从 350nm 到 2500nm。为了提高外量子效率（EQE）和探测率（D*），我们通过 EDT-PbSeQD/TABI PbSeQD 双层薄膜应用了空穴陷阱辅助光电倍增效应，其中 EDT-PbSe QD 是 1,2-乙二硫醇（EDT）封端的 PbSe QD，TABI-PbSe QD 是四丁基碘化铵（TABI）封端的 PbSe QD。为了进一步提高 D*，我们在 PbSeQD 基光电探测器中应用了一层共轭聚合物电解质，它在光照下由于光致自掺杂过程提供了显著的空穴注入电阻，抑制了暗电流，但增强了光电流，从而重新设计了电子提取层。结果表明，在室温下，基于 PbSeQD 的光电探测器在可见光区域的 EQE 超过 450%，D约为 10 琼斯，在红外区域的 EQE 超过 120%，D约为 4×10 琼斯。这些结果表明，我们的研究提供了一种实现室温工作的溶液处理宽带光电探测器的简单方法。
