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Alkyl-Engineered Dual-State Luminogens with Pronounced Odd-Even Effects: Quantum Yields with up to 48% Difference and
Yuanye Yin1, Aixiang Ding2, Felicia He3
1College of Chemistry and Chemical Engineering, Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University), Ministry of Education, Photoelectric Conversion Energy Materials and Devices Key Laboratory of Anhui Province, Anhui University, Hefei 230061, PR China.
Abstract:
Alkyl chain-resulted odd-even effects in fluorescence quantum yield (FLQY) have also been reported in organic luminescent materials (OLMs). However, the odd-even effects in FLQY caused by the alkyl substitutes in OLMs are generally very weak, with only single-digit differences. Here, we report a series of alkyl-substituted dual-state luminogens (DSEgens) showing extremely high solid-state FLQY in even-numbered analogues (>90% FLQY) and a dramatically pronounced odd-even effect in FLQY. The odd-even effect in FLQY is over 26% alternation, and a maximum of 48% difference in FLQY was observed between the compounds C1 and C2 with a methyl and ethyl substitution, respectively. C1 and C2 also displayed a crystallochromy with a 22 nm difference in emission wavelength. In addition, odd-even effects in the melting point and decomposition temperature were also observed. With these bright DSEgens, applications such as specific recognition of picric acid and ultrasensitive trace water detection have been demonstrated.
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