Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel.
Phys Rev Lett. 2010 Apr 16;104(15):157404. doi: 10.1103/PhysRevLett.104.157404.
The observed intermittent light emission from colloidal semiconductor nanocrystals has long been associated with Auger recombination assisted quenching. We test this view by observing transient emission dynamics of CdSe/CdS/ZnS semiconductor nanocrystals using time-resolved photon counting. The size and intensity dependence of the observed decay dynamics seem inconsistent with those expected from Auger processes. Rather, the data suggest that in the "off" state the quantum dot cycles in a three-step process: photoexcitation, rapid trapping, and subsequent slow nonradiative decay.
胶体半导体纳米晶体的间歇性光发射长期以来一直与俄歇复合辅助猝灭有关。我们通过使用时间分辨光致发光技术观察 CdSe/CdS/ZnS 半导体纳米晶体的瞬态发射动力学来检验这一观点。观察到的衰减动力学的尺寸和强度依赖性与预期的俄歇过程不一致。相反，数据表明在“关闭”状态下，量子点以三步过程循环：光激发、快速捕获和随后的缓慢非辐射衰减。
