Silver selenide colloidal quantum dots exhibit distinct optical absorption in the mid-wavelength infrared spectral region, which arises from the intraband transition between the first and the second quantum-confined energy levels. The optical absorption coefficient, carrier mobility, and carrier lifetime, which are the three primary parameters that determine the ultimate performance of a photodetector, are expected to be heavily dependent on the surface capping ligands. Herein, we characterize these parameters on silver selenide colloidal quantum dots films chemically treated with ligands selected from literatures that report high-performance quantum dot-based solar cells, photodetectors, transistors, and thermoelectrics. We correlate these results with the mid-infrared responsivities measured from photoconductive photodetectors fabricated from respective ligand-exchanged films. The insights gained from this study may serve as a foundation for enabling future intraband CQD-based MWIR sensing and imaging technologies.

硒化银胶体量子点在中波长红外光谱区显示出独特的光吸收，这是由第一和第二量子限制能级之间的带内跃迁引起的。光学吸收系数，载流子迁移率和载流子寿命是决定光电探测器最终性能的三个主要参数，它们在很大程度上取决于表面封盖配体。在这里，我们表征了用配体化学处理的硒化银胶体量子点薄膜上的这些参数，这些配体选自报道了基于高性能量子点的太阳能电池，光电探测器，晶体管和热电学的文献。我们将这些结果与由相应配体交换膜制造的光电导光电探测器测得的中红外响应度相关联。从这项研究中获得的见识可以为将来基于CQD的带内MWIR传感和成像技术的实现奠定基础。