Distance makes a difference in crystalline photoluminescence

Zibao Gan,Xuedan Ma,Shuqing Jiang,Lin Wang,Zhikun Wu,Xiang Wu,Wanmiao Gu,Lizhong He,Yungui Liu,Jaeyong Kim,Junran Zhang,Zhongyan Wu,Yanchun Li,Zhipeng Yan,Yixuan Xu,Jingwu Dong,Nan Xia

doi:10.1038/s41467-020-19377-6

Abstract

Crystallization-induced photoluminescence weakening was recently revealed in ultrasmall metal nanoparticles. However, the fundamentals of the phenomenon are not understood yet. By obtaining conformational isomer crystals of gold nanoclusters, we investigate crystallization-induced photoluminescence weakening and reveal that the shortening of interparticle distance decreases photoluminescence, which is further supported by high-pressure photoluminescence experiments. To interpret this, we propose a distance-dependent non-radiative transfer model of excitation electrons and support it with additional theoretical and experimental results. This model can also explain both aggregation-induced quenching and aggregation-induced emission phenomena. This work improves our understanding of aggregated-state photoluminescence, contributes to the concept of conformational isomerism in nanoclusters, and demonstrates the utility of high pressure studies in nanochemistry.

Highlights

Crystallization-induced photoluminescence weakening was recently revealed in ultrasmall metal nanoparticles
The structural isomers in gold NCs34 has been experimentally revealed by Tian, et al.[35], which inspired our enthusiasm to search for conformational isomerism in metal NCs
The Au60S7 NCs were etched with excess HSCH2Ph at 100 °C overnight, and the target NCs were isolated by preparative thin-layer chromatography (PTLC)

Summary

Introduction

Crystallization-induced photoluminescence weakening was recently revealed in ultrasmall metal nanoparticles. The structural isomers in gold NCs34 has been experimentally revealed by Tian, et al.[35], which inspired our enthusiasm to search for conformational isomerism in metal NCs. Very recently, Pradeep et al reported the quasi-conformational isomerism of [Ag29(BDT)12(TPP)4]3− in two different polymorphic forms by X-ray crystallography, cubic and trigonal, which were obtained by regulating the solvent for crystallization[36]. Pradeep et al reported the quasi-conformational isomerism of [Ag29(BDT)12(TPP)4]3− in two different polymorphic forms by X-ray crystallography, cubic and trigonal, which were obtained by regulating the solvent for crystallization[36] It is not definite yet whether they are strictly conformational isomers since the complete formula (including the counter ions) was not given in either case[36,37]. We obtain conformational isomers of gold NCs and investigate the crystalline PL in depth

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Results

Conclusion