Wang Xiao, Song Zhulu, Tang Haodong, Li Yiwen, Zhong Huaying, Wu Jiufeng, Wang Weichao, Chen Simin, Zhang Wenjie, Fang Fan, Hao Junjie, Wu Dan, Müller-Buschbaum Peter, Cao Leifeng, Tang Zeguo, Tang Jun, Zhang Lei, Wang Kai, Chen Wei
Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Intense Laser Application Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, China.
School of Materials Science and Engineering, Hubei University, Wuhan 430062, China.
ACS Appl Mater Interfaces. 2024 Aug 21;16(33):44164-44173. doi: 10.1021/acsami.4c05201. Epub 2024 Aug 1.
PbS quantum dots (QDs) are promising for short-wave infrared (SWIR) photodetection and imaging. Solid-state ligand exchange (SSLE) is a low-fabrication-threshold QD solid fabrication method. However, QD treatment by SSLE remains challenging in seeking refined surface passivation to achieve the desired device performance. This work investigates using NaAc in the ligand exchange process to enhance the film morphology and electronic coupling configuration of QD solids. By implementing various film and photodetector device characterization studies, we confirm that adding NaAc with a prominent adding ratio of 20 wt % NaAc with tetrabutylammonium iodide (TBAI) in the SSLE leads to an improved film morphology, reduced surface roughness, and decreased trap states in the QD solid films. Moreover, compared to the devices without NaAc treatment, those fabricated with NaAc-treated QD solids exhibit an enhanced performance, including lower dark current density (<100 nA/cm), faster response speed, higher responsivity, detectivity, and external quantum efficiency (EQE reaching 25%). The discoveries can be insightful in developing efficient, low-cost, and low-fabrication-threshold QD SWIR detection and imager applications.
硫化铅量子点（QDs）在短波红外（SWIR）光电探测和成像方面具有广阔前景。固态配体交换（SSLE）是一种低制备门槛的量子点固体制造方法。然而，通过SSLE进行量子点处理在寻求精细的表面钝化以实现所需器件性能方面仍然具有挑战性。这项工作研究了在配体交换过程中使用醋酸钠来改善量子点固体的薄膜形态和电子耦合构型。通过进行各种薄膜和光电探测器器件表征研究，我们证实，在SSLE中加入占比20 wt%的醋酸钠（与碘化四丁基铵（TBAI）一起），会使量子点固体薄膜的形态得到改善、表面粗糙度降低且陷阱态减少。此外，与未经醋酸钠处理的器件相比，用经醋酸钠处理的量子点固体制备的器件性能得到增强，包括更低的暗电流密度（<100 nA/cm²）、更快的响应速度、更高的响应度、探测率和外部量子效率（EQE达到25%）。这些发现对于开发高效、低成本且低制备门槛的量子点SWIR探测和成像应用具有重要意义。
