Yonemoto Daniel T, Papa Christopher M, Mongin Cedric, Castellano Felix N
Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States.
Laboratoire PPSM, ENS Paris-Saclay, 61 Avenue du Président Wilson, 94235 Cachan CEDEX, France.
J Am Chem Soc. 2020 Jun 24;142(25):10883-10893. doi: 10.1021/jacs.0c03331. Epub 2020 Jun 11.
Thermally activated photophysical processes are ubiquitous in numerous organic and metal-organic molecules, leading to chromophores with excited-state properties that can be considered an equilibrium mixture of the available low-lying states. Relative populations of the equilibrated states are governed by temperature. Such molecules have been devised as high quantum yield emitters in modern organic light-emitting diode technology and for deterministic excited-state lifetime control to enhance chemical reactivity in solar energy conversion and photocatalytic schemes. The recent discovery of thermally activated photophysics at CdSe nanocrystal-molecule interfaces enables a new paradigm wherein molecule-quantum dot constructs are used to systematically generate material with predetermined photophysical response and excited-state properties. Semiconductor nanomaterials feature size-tunable energy level engineering, which considerably expands the purview of thermally activated photophysics beyond what is possible using only molecules. This Perspective is intended to provide a nonexhaustive overview of the advances that led to the integration of semiconductor quantum dots in thermally activated delayed photoluminescence (TADPL) schemes and to identify important challenges moving into the future. The initial establishment of excited-state lifetime extension utilizing triplet-triplet excited-state equilibria is detailed. Next, advances involving the rational design of molecules composed of both metal-containing and organic-based chromophores that produce the desired TADPL are described. Finally, the recent introduction of semiconductor nanomaterials into hybrid TADPL constructs is discussed, paving the way toward the realization of fine-tuned deterministic control of excited-state decay. It is envisioned that libraries of synthetically facile composites will be broadly deployed as photosensitizers and light emitters for numerous synthetic and optoelectronic applications in the near future.
热激活光物理过程在众多有机和金属有机分子中普遍存在，导致发色团具有激发态性质，这些性质可被视为可用低能态的平衡混合物。平衡态的相对丰度受温度控制。这类分子已被设计用于现代有机发光二极管技术中的高量子产率发射体，以及用于确定性激发态寿命控制，以增强太阳能转换和光催化方案中的化学反应性。最近在CdSe纳米晶体 - 分子界面发现的热激活光物理现象开启了一种新范式，即分子 - 量子点结构被用于系统地生成具有预定光物理响应和激发态性质的材料。半导体纳米材料具有尺寸可调的能级工程特性，这大大扩展了热激活光物理的范围，远超仅使用分子时的可能性。本视角旨在对导致半导体量子点集成到热激活延迟光致发光（TADPL）方案中的进展进行非详尽概述，并确定未来面临的重要挑战。详细介绍了利用三重态 - 三重态激发态平衡实现激发态寿命延长的初步成果。接下来，描述了涉及由含金属和有机发色团组成的分子的合理设计的进展，这些分子能产生所需的TADPL。最后，讨论了最近将半导体纳米材料引入混合TADPL结构的情况，为实现激发态衰变的精细确定性控制铺平了道路。预计在不久的将来，合成简便的复合材料库将被广泛用作众多合成和光电应用的光敏剂和发光体。
