Since the emergence of the first green light emission from a fluorescent thin-film organic light emitting diode (OLED) in the mid-1980s, a global consumer market for OLED displays has flourished over the past few decades. This growth can primarily be attributed to the development of noble metal phosphorescent emitters that facilitated remarkable gains in electrical conversion efficiency, a broadened color gamut, and vibrant image quality for OLED displays. Despite these achievements, the limited abundance of noble metals in the Earth’s crust has spurred ongoing efforts to discover cost-effective electroluminescent materials. One particularly promising avenue is the exploration of thermally activated delayed fluorescence (TADF), a mechanism with the potential to fully harness excitons in OLEDs. Recently, investigations have unveiled TADF in a series of two-coordinate coinage metal (Cu, Ag, and Au) complexes. These organometallic TADF materials exhibit distinctive behavior in comparison to their organic counterparts. They offer benefits such as tunable emissive colors, short TADF emission lifetimes, high luminescent quantum yields, and reasonable stability. Impressively, both vacuum-deposited and solution-processed OLEDs incorporating these materials have achieved outstanding performance. This review encompasses various facets on two-coordinate TADF coinage metal complexes, including molecular design, photophysical characterizations, elucidation of structure–property relationships, and OLED applications.

中文翻译：

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二配位热激活延迟荧光金属配合物：分子设计、光物理特性和器件应用

自 20 世纪 80 年代中期荧光薄膜有机发光二极管 (OLED) 首次出现绿光以来，OLED 显示器的全球消费市场在过去几十年中蓬勃发展。这一增长主要归功于贵金属磷光发射体的开发，该发射体显着提高了 OLED 显示器的电转换效率、拓宽的色域和鲜艳的图像质量。尽管取得了这些成就，但地壳中贵金属的丰富程度有限，促使人们不断努力发现具有成本效益的电致发光材料。一个特别有前景的途径是探索热激活延迟荧光（TADF），这是一种有潜力充分利用 OLED 中激子的机制。最近，研究揭示了一系列二配位造币金属（铜、银和金）配合物中的 TADF。与有机材料相比，这些有机金属 TADF 材料表现出独特的行为。它们具有可调发射颜色、短 TADF 发射寿命、高发光量子产率和合理的稳定性等优点。令人印象深刻的是，采用这些材料的真空沉积和溶液处理 OLED 都取得了出色的性能。本综述涵盖了二配位 TADF 造币金属配合物的各个方面，包括分子设计、光物理表征、结构-性能关系的阐明以及 OLED 应用。