Paul Provakar, Karar Monaj, Mondal Bibhas, Roy Ujjal Kanti, Ghosh Ashutosh, Majumdar Tapas, Mallick Arabinda
Department of Chemistry, University of Kalyani, Nadia, West Bengal, 741235, India.
Department of Chemistry, Kazi Nazrul University, Asansol, West Bengal, 713340, India.
Phys Chem Chem Phys. 2022 Aug 3;24(30):18245-18254. doi: 10.1039/d2cp02305a.
Organic molecules with tunable fluorescence quantum yield are attractive for opto-electronic applications. A fluorophore with tunable fluorescence quantum yield should be a better choice for a variety of applications that demand fluorophores with different quantum yields. Here organic emitters with a continuous bell-shaped fluorescence yield profile would be promising in view of sustainability and reusability; however, fluorophores with these properties are rarely reported. A bis-indole derivative, 3,3'-bisindolyl(phenyl)methane (BIPM), was synthesised and found to undergo a unique 'rise-and-fall' profile in fluorescence yield with a compositional change of the 1,4-dioxane (DiOx)-HO solvent system. A predominant interplay of two contrasting factors, (a) polarity and proticity induced emission enhancement and (b) aggregation caused fluorescence quenching, on either side of a crossover solvent composition (∼50% ), resulted in a continuous bell-patterned fluorescence yield profile. Interestingly, these two factors could be observed individually or simultaneously by adjusting the HO fraction. Detailed spectroscopic, electron microscopic and computational studies have been performed to substantiate the photophysics behind the solvent regulated modulation of fluorescence quantum yield.
具有可调荧光量子产率的有机分子在光电子应用中具有吸引力。对于各种需要不同量子产率荧光团的应用而言，具有可调荧光量子产率的荧光团应该是更好的选择。鉴于可持续性和可重复使用性，具有连续钟形荧光产率分布的有机发光体可能很有前景；然而，具有这些特性的荧光团鲜有报道。合成了一种双吲哚衍生物3,3'-双吲哚基（苯基）甲烷（BIPM），发现其在1,4-二氧六环（DiOx）-水溶剂体系组成变化时，荧光产率呈现独特的“先升后降”分布。在交叉溶剂组成（约50%）两侧，两个相反因素（a）极性和质子性诱导发射增强以及（b）聚集导致荧光猝灭之间的主要相互作用，导致了连续的钟形荧光产率分布。有趣的是，通过调节水的比例，可以分别或同时观察到这两个因素。已进行了详细的光谱、电子显微镜和计算研究，以证实溶剂调节荧光量子产率背后的光物理过程。
