Radiative and Nonradiative Recombination in CuInS2 Nanocrystals and CuInS2-Based Core/Shell Nanocrystals
Radiative and Nonradiative Recombination in CuInS2 Nanocrystals and CuInS2-Based Core/Shell Nanocrystals
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DOI：
10.1021/acs.jpclett.6b01668
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发表时间：
2016-09-01
影响因子：
5.7
通讯作者：
Donega, Celso de Mello
中科院分区：
文献类型：
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作者：
Berends, Anne C.;Rabouw, Freddy T.;Donega, Celso de Mello
发光硫化铜铟（CIS）纳米晶体是一种潜在的解决与镉和铅基纳米晶体相关的毒性问题的方法。然而，由于对电子结构和导致发光猝灭的因素了解不足，使得高质量CIS纳米晶体的开发变得复杂。本文利用时间分辨光致发光和瞬态吸收光谱研究了CIS纳米晶体中的激子衰变途径。将低量子产率的单核CIS纳米晶体与量子产率较高的单核/壳纳米晶体（CIS/ZnS和CIS/CdS）进行了比较。我们的测量结果支持了传导带电子与局域空穴辐射复合的光致发光模型。此外，我们发现低量子产率纳米晶体中的光致发光猝灭涉及电子和空穴最初不耦合的衰变途径。电子衰变途径决定了激子是辐射重组还是非辐射重组。因此，高质量CIS纳米晶体的开发应侧重于消除电子陷阱。
Luminescent copper indium sulfide (CIS) nanocrystals are a potential solution to the toxicity issues associated with Cd- and Pb-based nanocrystals. However, the development of high-quality CIS nanocrystals has been complicated by insufficient knowledge of the electronic structure and of the factors that lead to luminescence quenching. Here we investigate the exciton decay pathways in CIS nanocrystals using time resolved photoluminescence and transient absorption spectroscopy. Core-only CIS nanocrystals with low quantum yield are compared to core/shell nanocrystals (CIS/ZnS and CIS/CdS) with higher quantum yield. Our measurements support the model of photoluminescence by radiative recombination of a conduction band electron with a localized hole. Moreover, we find that photoluminescence quenching in low-quantum-yield nanocrystals involves initially uncoupled decay pathways for the electron and hole. The electron decay pathway determines whether the exciton recombines radiatively or nonradiatively. The development of high-quality CIS nanocrystals should therefore focus on the elimination of electron traps.