Electrochemiluminescence (ECL) has gained renewed interest due to the strong parallel development of luminophores in the field of organic light emitting diodes (OLEDs) with which this technique shares several aspects. In this prospective review we discuss the most relevant advances of the past 15 years in the study of organic and organometallic compounds as ECL emitters, by dividing them in three different classes: i) fluorescent emitters, ii) phosphorescent emitters and iii) Thermally Activated Delayed Fluorescence (TADF) emitters; then, water‐soluble organic luminophore will be also discussed. We focus on how their design, their photo‐ and electrochemical properties and, in particular, the nature of the emitter, affects their efficiency in ECL. Regardless of the type of luminophore or the photoluminescence quantum yield (PLQY), the literature converges on the fact that the most determining aspect is the stability of the oxidized/reduced form of the emitter. Even if phosphorescent emitters can show outstanding efficiency, this often requires the absence of oxygen. In the case of TADFs, there is also a strong dependence of photoluminescence both in terms of PLQY and emission energy on the polarity of the media, so compounds that appear promising in organic solvents may be very inefficient in aqueous media.

中文翻译：

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电化学发光 (ECL) 应用小分子设计的关键方面和挑战

由于有机发光二极管 (OLED) 领域中发光体的强劲并行发展，电化学发光 (ECL) 重新引起了人们的兴趣，该技术与有机发光二极管 (OLED) 领域有几个共同点。在这篇前瞻性综述中，我们讨论了过去 15 年在有机和有机金属化合物作为 ECL 发射体的研究中最相关的进展，将它们分为三个不同的类别：i) 荧光发射体，ii) 磷光发射体和 iii) 热激活延迟发射体荧光（TADF）发射器；然后，还将讨论水溶性有机发光体。我们重点关注它们的设计、光和电化学特性，特别是发射器的性质，如何影响它们的 ECL 效率。无论发光体的类型或光致发光量子产率（PLQY）如何，文献都集中在这样一个事实：最具决定性的方面是发射体的氧化/还原形式的稳定性。即使磷光发射体可以表现出出色的效率，但这通常需要没有氧气。就 TADF 而言，光致发光的 PLQY 和发射能量都对介质的极性有很强的依赖性，因此在有机溶剂中看起来很有前景的化合物在水介质中可能效率非常低。