Triplet harvesting in trifluoromethyl quinoxaline derivatives via TADF and RTP mechanisms

IF 3.8 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Optical Materials Pub Date : 2024-11-12 DOI:10.1016/j.optmat.2024.116421

Rita Butkute , Tomas Serevicius , Steponas Raisys , Kamile Tulaite , Levani Skhirtladze , Gjergji Sini , Juozas Vidas Grazulevicius , Saulius Jursenas

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引用次数: 0

Abstract

In this study, we explore the impact of donor strength on the photophysical properties of novel trifluoromethyl quinoxaline derivatives, which incorporate various electron-donating moieties exhibiting distinct conformational characteristics. The triplet harvesting mechanisms within these quinoxaline systems are facilitated through thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP), both of which can be modulated by subtle structural alterations in the donor unit. The derivatives demonstrate varying photophysical properties, including pure RTP activity, dual activity (exhibiting both TADF and RTP), and pure TADF, contingent upon the nature of the electron-donating moieties employed. Notably, the intersystem crossing (ISC) rates are significantly higher than the rates of radiative decay, leading to diminished fluorescence quantum yields (Φ_DF) of the compounds in toluene solutions. However, embedding the TADF compounds within a rigid polystyrene (PS) matrix results in a remarkable enhancement of Φ_DF due to significant reduction of nonradiative pathways related to intramolecular twisting. A considerable conformational disorder of the polymer doped films was observed resulting in non-exponential fluorescence decay and significant shifts of prompt and delayed fluorescence in time-resolved spectra.

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通过 TADF 和 RTP 机制实现三氟甲基喹喔啉衍生物中的三重子收获

在本研究中，我们探讨了供体强度对新型三氟甲基喹喔啉衍生物光物理特性的影响，这些衍生物含有各种电子供体，具有不同的构象特性。这些喹喔啉系统中的三重捕获机制是通过热激活延迟荧光（TADF）和室温磷光（RTP）来实现的，而这两种机制都可以通过供体单元中微妙的结构变化来调节。这些衍生物表现出不同的光物理特性，包括纯 RTP 活性、双重活性（同时表现出 TADF 和 RTP）和纯 TADF，这取决于所采用的电子供体的性质。值得注意的是，系统间交叉（ISC）速率明显高于辐射衰变速率，导致这些化合物在甲苯溶液中的荧光量子产率（ΦDF）降低。然而，将 TADF 化合物嵌入刚性聚苯乙烯（PS）基质中，由于与分子内扭转有关的非辐射途径大大减少，ΦDF 得到了显著提高。据观察，掺杂聚合物的薄膜存在相当大的构象紊乱，导致非指数荧光衰减以及时间分辨光谱中迅速荧光和延迟荧光的显著偏移。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Optical Materials 工程技术-材料科学：综合

CiteScore

6.60

自引率

12.80%

发文量

1265

审稿时长

38 days

期刊介绍： Optical Materials has an open access mirror journal Optical Materials: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review. The purpose of Optical Materials is to provide a means of communication and technology transfer between researchers who are interested in materials for potential device applications. The journal publishes original papers and review articles on the design, synthesis, characterisation and applications of optical materials. OPTICAL MATERIALS focuses on: • Optical Properties of Material Systems; • The Materials Aspects of Optical Phenomena; • The Materials Aspects of Devices and Applications. Authors can submit separate research elements describing their data to Data in Brief and methods to Methods X.