Department of Chemistry, Kyung Hee University, Seoul 130-701, Korea.
Department of Chemistry, Kookmin University, Seoul 136-702, Korea.
Nanoscale. 2017 Jul 27;9(29):10285-10291. doi: 10.1039/c7nr02380d.
The photoluminescence of AgInS nanoparticles was examined to clarify the emissive relaxation processes of defect states and to explain the highly efficient photoluminescence of defect states. The large Stokes shift of the defect emission was explained by strong electron-phonon coupling in the nanoparticles. Steady-state and time-resolved photoluminescence spectroscopy indicated two emissive defect states with characteristic emission energies and lifetimes. Change of the surface-to-volume ratio in the nanoparticles affected the relative contribution of the two states, implying that defect emission in higher energy was attributable to surface-related defects. The defect emission in lower energy was attributable to intrinsic defects, which were also present in bulk. The quantum yield of the surface defects was larger than that of the intrinsic defects, which accounted for the unusually high quantum yield of AgInS nanoparticles, although the origin of emission was the defect states, not the exciton recombination found in typical semiconductor nanoparticles.
AgInS 纳米颗粒的光致发光被检测，以澄清缺陷态的发射弛豫过程，并解释缺陷态的高效光致发光。缺陷发射的大斯托克斯位移由纳米颗粒中强的电子-声子耦合解释。稳态和时间分辨光致发光光谱表明，两种发射缺陷态具有特征的发射能量和寿命。纳米颗粒中表面-体积比的变化影响了两种状态的相对贡献，表明高能缺陷发射归因于与表面相关的缺陷。较低能量的缺陷发射归因于本征缺陷，本征缺陷也存在于体相中。表面缺陷的量子产率大于本征缺陷的量子产率，这解释了 AgInS 纳米颗粒异常高的量子产率，尽管发射的起源是缺陷态，而不是典型半导体纳米颗粒中发现的激子复合。
