Distance makes a difference in crystalline photoluminescence

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.

Source of Bright Near-Infrared Luminescence in Gold Nanoclusters

“…Significant enhancement of PL achieved by rigidifying the surface of the nanocluster was reported by the Lee group, and surface-regulated PL enhancement was reported by the Millstone, Tsukuda, and Wu groups. Aggregation-induced emission was introduced by the Xie group, and such a phenomenon was also reported by the Zhu, Konishi, and Wu groups. Recently, Narouz et al reported a highly luminescent Au 13 nanocluster protected by N -heterocyclic carbenes which shows a 16% QY in solvent.…”

Synthesis of Ag2S Based Quantum Dots with Near-infrared-II Fluorescence Emission in Water

“…其中, 以王强 斌团队 [11] 发现和研究的新型 Ag 2 S 基近红外 II 区荧光量 子点体系最具代表性. 尽管 Ag 2 S 基量子点的光致发光 效率很难与 Cd、Pb、Hg 基半导体量子点竞争, 但其稳 定的理化性质和优异的生物相容性使其成为近 10 年来 研究最多的近红外活体荧光探针 [11][12][13][14][15][16][17][18][19][20][21] . 量子点荧光探针的发展在一定程度上受到化学合 成工艺的影响.…”

Boosting the photodynamic therapy of near-infrared AIE-active photosensitizers by precise manipulation of the molecular structure and aggregate-state packing

“…21–23 Subtle intermolecular microenvironment 24,25 changes usually induce the formation of different packing motifs composed of H-aggregates and J-aggregates, thus leading to various performances. 26–30 Therefore, ingenious modulation of molecular structures as well as intra/intermolecular interactions could endow the materials with desired characteristics and provide an ideal arena for understanding some mechanistic issues at a strictly molecular level, such as diverse aggregation-related photophysical processes.…”