Effect of energy transfer on the optical properties of surface-passivated perovskite films with CdSe/ZnS quantum dots
Effect of energy transfer on the optical properties of surface-passivated perovskite films with CdSe/ZnS quantum dots
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DOI：
10.1038/s41598-019-54860-1
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发表时间：
2019-12-05
影响因子：
4.6
通讯作者：
Ryu, Mee-Yi
中科院分区：
文献类型：
--
作者：
Cho, Il-Wook;Ryu, Mee-Yi
表面钝化是保护钙钛矿(PS)薄膜表面、提高其发光性能的一种有效方法。由于CdSe/ZnS核壳量子点具有大小可调的带隙特性，已被用于PS膜的表面钝化。本文用光致发光(PL)和时间分辨光致发光(PL)谱研究了覆盖有CdSe/ZnS量子点(QD/PS杂化结构)的CH(3)NH(3)PbL(2)BrPS薄膜的能量转移(ET)行为。QD/PS杂化结构的光致发光衰减时间和积分光致发光强度比裸PS膜增加，这是由于量子点到PS层的电子转移和电荷陷阱的减少所致。当量子点的芯径从6.5 nm减小到2.7 nm时，量子点/多孔硅杂化结构的电子转移效率从类似的7%提高到63%。这可以通过控制量子点的能级排列来提高电荷转移速率来解释。这些结果使我们能够理解基本的机制，如从量子点到PS膜的ET作为量子点大小的函数。
Surface passivation is an effective method to protect the surfaces and improve the luminescence properties of perovskite (PS) films. CdSe/ZnS core-shell quantum dots (QDs) have been employed for surface passivation of PS films because of their size-dependent tunable bandgaps. Herein, the energy transfer (ET) behavior of CH(3)NH(3)Pbl(2)Br PS films covered with CdSe/ZnS QDs (QD/PS hybrid structures) is characterized by using photoluminescence (PL) and time-resolved PL spectroscopy. The PL decay time and the integrated PL intensity of the QD/PS hybrid structure increase compared with those of the bare PS films, owing to ET from the QDs to the PS and reduced charge traps. The ET efficiency increases from similar to 7% to 63% for the QD/PS hybrid structure when the core diameter of the QDs decreases from 6.5 to 2.7 nm, respectively. This can be explained by the charge transfer rate enhancement due to the control of energy level alignment of QDs. These results allow us to understand fundamental mechanisms such as ET from QDs to PS films as a function of the size of the QD.