Yonemoto Daniel T, Papa Christopher M, Sheykhi Sara, Castellano Felix N
Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States.
J Phys Chem Lett. 2021 Apr 22;12(15):3718-3723. doi: 10.1021/acs.jpclett.1c00746. Epub 2021 Apr 9.
Quantum-dot/molecule composites (QD/mol) have demonstrated useful photochemical properties for many photonic and optoelectronic applications; however, a comprehensive understanding of these materials remains elusive. This work introduces a series of cadmium(II) selenide/1-pyrenecarboxylic acid (CdSe/PCA) nanomaterials featuring bespoke PCA surface coverage on CdSe585 (coded by the peak of the first exciton absorption band) to glean insight into the QD/mol photophysical behavior. Tailoring the energy gap between the CdSe585 first exciton band (2.1 eV) and the lowest PCA triplet level (T = 2.0 eV) to be nearly isoenergetic, strong thermally activated delayed photoluminescence (TADPL) is observed resulting from reverse triplet-triplet energy transfer. The resultant average decay time constant (τ) of the photoluminescence emanating from CdSe585 is deterministically controlled with surface-bound PCA chromophores ( = average number of adsorbed PCA molecules) by shifting the triplet excited state equilibrium from the CdSe585 to the PCA molecular triplet reservoir as a function of .
量子点/分子复合材料（QD/mol）已在许多光子和光电子应用中展现出有用的光化学性质；然而，对这些材料的全面理解仍然难以捉摸。这项工作介绍了一系列硒化镉（II）/1-芘甲酸（CdSe/PCA）纳米材料，其在CdSe585上具有定制的PCA表面覆盖率（由第一个激子吸收带的峰值编码），以深入了解QD/mol的光物理行为。通过将CdSe585的第一个激子带（2.1 eV）与最低的PCA三重态能级（T = 2.0 eV）之间的能隙调整为几乎等能，观察到由于反向三重态-三重态能量转移而产生的强烈热激活延迟光致发光（TADPL）。通过表面结合的PCA发色团（ = 吸附的PCA分子平均数），通过将三重态激发态平衡从CdSe585转移到PCA分子三重态库作为 的函数，确定性地控制源自CdSe585的光致发光的平均衰减时间常数（τ）。
