How Pendant Groups Dictate Energy and Electron Transfer in Perovskite-Rhodamine Light Harvesting Assemblies
How Pendant Groups Dictate Energy and Electron Transfer in Perovskite-Rhodamine Light Harvesting Assemblies
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DOI：
10.1021/jacs.2c12248
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发表时间：
2023-02-16
影响因子：
15
通讯作者：
Kamat, Prashant, V
中科院分区：
文献类型：
--
作者：
DuBose, Jeffrey T.;Kamat, Prashant, V
能量和电子转移过程允许在光催化和光电子应用中有效地操纵光收集组件中的激发态。我们现在已经成功地探索了受体侧基官能化对CsPbBr3钙钛矿纳米晶与三个罗丹明类受体分子之间能量和电子转移的影响。这三种受体--罗丹明B(RhB)、罗丹明异硫氰酸酯(RhB-NCS)和孟加拉玫瑰(RoseB)--含有越来越多的侧基官能化，这影响了它们的天然激发态性质。当与CsPbBr3作为能量供体相互作用时，光致发光激发光谱显示三种受体都发生了单线态能量转移。然而，受主功能化直接影响决定激发态相互作用的几个关键参数。例如，RoseB结合在纳米晶表面的表观缔合常数(Kapp=9.4×106M-1)是RhB(Kapp=0.05×106M-1)的200倍，从而影响了能量转移速率。飞秒瞬时吸收显示，观测到的单线态能量转移速率常数(Kent=1×1011 S-1)比RhB和RhB-NCS大一个数量级。除了能量转移，每个受体都有一个分子亚群(类似于30%)，这些分子作为竞争途径进行电子转移。因此，在纳米晶-分子杂化材料中，无论是激发态能量还是电子转移都必须考虑受主基团的结构影响。电子和能量转移之间的竞争进一步突显了纳米晶体分子络合物中激发态相互作用的复杂性，以及需要仔细的光谱分析来阐明竞争路径。
Energy and electron transfer processes allow for efficient manipulation of excited states within light harvesting assemblies for photocatalytic and optoelectronic applications. We have now successfully probed the influence of acceptor pendant group functionalization on the energy and electron transfer between CsPbBr3 perovskite nanocrystals and three rhodaminebased acceptor molecules. The three acceptors-rhodamine B (RhB), rhodamine isothiocyanate (RhB-NCS), and rose Bengal (RoseB)-contain an increasing degree of pendant group functionalization that affects their native excited state properties. When interacting with CsPbBr3 as an energy donor, photoluminescence excitation spectroscopy reveals that singlet energy transfer occurs with all three acceptors. However, the acceptor functionalization directly influences several key parameters that dictate the excited state interactions. For example, RoseB binds to the nanocrystal surface with an apparent association constant (Kapp = 9.4 x 106 M-1) 200 times greater than RhB (Kapp = 0.05 x 106 M-1), thus influencing the rate of energy transfer. Femtosecond transient absorption reveals the observed rate constant of singlet energy transfer (kEnT) is an order-of-magnitude greater for RoseB (kEnT = 1 x 1011 s-1) than for RhB and RhB-NCS. In addition to energy transfer, each acceptor had a subpopulation of molecules (similar to 30%) that underwent electron transfer as a competing pathway. Thus, the structural influence of acceptor moieties must be considered for both excited state energy and electron transfer in nanocrystal-molecular hybrids. The competition between electron and energy transfer further highlights the complexity of excited state interactions in nanocrystalmolecular complexes and the need for careful spectroscopic analysis to elucidate competitive pathways.