Charge-Transfer Dynamics between Cesium Lead Halide Perovskite Nanocrystals and Surface-Anchored Naphthalimide Acceptors
Charge-Transfer Dynamics between Cesium Lead Halide Perovskite Nanocrystals and Surface-Anchored Naphthalimide Acceptors
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DOI：
10.1021/acs.jpcc.1c02622
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发表时间：
2021-07
期刊：
影响因子：
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通讯作者：
Meng Li;Silvano R. Valandro;Ru He;Yan Zhao;P. Yang;K. Schanze
中科院分区：
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作者：
Meng Li;Silvano R. Valandro;Ru He;Yan Zhao;P. Yang;K. Schanze
一系列1，8-萘酰亚胺（NI）电子受体通过不同长度的-（CH 2）n-连接基团与酰亚胺的N-位相连，可以猝灭CsPbBr 3纳米晶（NC）的光致发光（PL）.研究了三种基于NI的猝灭剂，NI-1、NI-2和NI-3，其中n分别为2、8和12。荧光猝灭归因于光诱导电子从CsPbBr 3 NCs的激子态转移到萘酰亚胺受体。缺乏NH 2基团的NI受体不淬灭PL，这表明氨基用于将受体锚到NC的表面。皮秒瞬态吸收（TA）支持光诱导电荷转移机制，其发现具有表面锚定NI-1受体的CsPbBr 3 NC的长寿命漂白（>7 ns）。对稳态和时间分辨的PL猝灭进行Stern-Volmer（SV）分析。结果表明，Ni-1、Ni-2、Ni-3的淬火效率顺序为：Ni-1> Ni-2 > Ni-3，其KSV值从Ni-1的106 M-1到Ni-3的105 M-1。稳态淬火和动态淬火的淬火效率大致相同。结果被解释的激子猝灭动力学的机制，其中控制的界面电子转移的速率。CsPbBr 3激子的扩散和/或脱陷也可能在决定淬灭速率中起作用。
A series of 1,8-naphthalimide (NI) electron acceptors with a primary amine functional group linked to the N-position of the imide by −(CH2)n– linkers with varying lengths are found to quench the photoluminescence (PL) of CsPbBr3nanocrystals (NC). Three NI-based quenchers were explored, NI-1, NI-2, and NI-3, withn= 2, 8, and 12, respectively. The PL quenching is attributed to photoinduced electron transfer from the exciton state of the CsPbBr3NCs to the naphthylimide acceptor. An NI acceptor that lacks the NH2group does not quench the PL, which reveals that the amino group serves to anchor the acceptors to the surface of the NC. The photoinduced charge-transfer mechanism is supported by picosecond transient absorption (TA), which finds a long-lifetime bleach (>7 ns) for the CsPbBr3NCs with surface-anchored NI-1 acceptors. Steady-state and time-resolved PL quenching was subjected to Stern–Volmer (SV) analysis. The results show that the quenching efficiency varies in the order NI-1 ≫ NI-2 > NI-3, withKSVranging from ∼106M–1for NI-1 to ∼105M–1for NI-3. The quenching efficiency is approximately the same for steady-state and dynamic quenching. The results are interpreted by a mechanism where the exciton quenching dynamics is controlled by the rate of interfacial electron transfer. Diffusion and/or detrapping of the CsPbBr3exciton may also play a role in determining the rate of quenching.