Positive Aging Effect of ZnO Nanoparticles Induced by Surface Stabilization

作者：Wenjuan Zhang, Xingtong Chen, Yuhui Ma, Zhiwei Xu, Longjia Wu, Yixing Yang, Sai‐Wing Tsang, Song Chen · 发表于：The Journal of Physical Chemistry Letters · 年份：2020 · DOI：10.1021/acs.jpclett.0c01640 · 被引用次数：78 · 研究领域：ZnO doping and properties、Quantum Dots Synthesis And Properties、Chalcogenide Semiconductor Thin Films

For quantum-dot photodiodes comprising an electron-transporting layer assembled of ZnO nanoparticles, the light emitter/absorber generally exhibits enhanced optoelectronic performance after the device is shelf-aged. To understand the so-called positive aging effect, the optoelectronic properties of ZnO nanoparticles are investigated at the thin film and device level as a function of aging time. It is evidenced that the aging process is driven by a surface-stabilizing mechanism of ZnO nanoparticles, in which the active surface adsorption sites for oxygen are gradually but irreversibly stabilized, i.e.. with surface termination of HO-ZnO, leading to reduced nonradiative recombination and increased built-in potential in the adjacent photoactive layer. This work provides insight into new synthetic routes for minimizing the negative impact caused by the aging process.