Cation Crosslinking-Induced Stable Copper Nanoclusters Powder as Latent Fingerprints Marker.

Yi Qiu,Zhongjie Cui,Jinxin Wei,Ruiqian Guo,Wanlu Zhang,Zhuoqi Wen,Shiliang Mei,Fengxian Xie,Yuanyuan Chen,Zhe Hu

doi:10.3390/nano11123371

Abstract

Luminescent copper nanoclusters (Cu NCs) have shown great potential in light-emitting devices (LEDs), chemical sensing, catalysis and biological fields. However, their practical use has been restricted by poor stability, and study on the stability of Cu NCs solid powder along with the mechanism is absent. In this study, stablized Cu NCs powder was first obtained by cation crosslinking method. Compared with the powder synthesized by solvent precipitation method, the stability of Cu NCs powder crosslinked by ionic inducer Ce3+ was enhanced around 100-fold. The storage time when the fluorescence intensity decreased to 85% (T85) was improved from 2 h to 216 h, which is the longest so far. The results of characterizations indicated that the aggregation structure was formed by the binding of Ce3+ with the capping ligands of Cu NCs, which helped in obtaining Ce-Cu NCs powder from aggregate precipitation in solution. Furthermore, this compact structure could avoid the destruction of ambient moisture resulting in long-lasting fluorescence and almost unchanged physical form. This demonstrated that phosphor, with excellent characteristics of unsophisticated synthesis, easy preservation and stable fluorescence, showed great potential in light sources, display technology and especially in latent fingerprints visualization on different substrates for forensic science.

Highlights

Metal nanoclusters exhibit excellent luminescence properties such as molecular electronic transitions, bright luminescence and tunable emission wavelength owing to their ultra-small size and discrete energy levels [1,2,3]
We introduced solvent precipitation method and cation crosslinking method to synthesize Cu NCs powder
We introduced a novel cation crosslinking method to obtain stable Cu NCs powder

Summary

Introduction

Metal nanoclusters exhibit excellent luminescence properties such as molecular electronic transitions, bright luminescence and tunable emission wavelength owing to their ultra-small size and discrete energy levels [1,2,3]. Comparing with noble metal nanoclusters, copper nanoclusters (Cu NCs) are becoming popular research candidates due to the abundant raw materials, low biotoxicity and low cost, which have shown great value in applications of light-emitting devices (LEDs) [4,5,6], chemical sensing [7,8,9], catalysis [10] and biological fields [11,12,13]. There are mainly three strategies: inducing thiol-protected Cu NCs to aggregate [15,16,17,18], selecting suitable capping ligands [19,20,21,22] and combining Cu NCs with other materials [11,14,23,24,25].

Methods

Results

Conclusion