X-ray-triggered through-space charge transfer and photochromism in silver nanoclusters

• Published in: Nanoscale 2024-02, Vol.16 (5), p.2662-2671
• Main Authors: Ren, Zhen, Sun, Jun-Jun, Xu, Long, Luo, Peng, Ma, Zi-Wei, Li, Si, Si, Yu-Bing, Dong, Xi-Yan, Pan, Fangfang
• Format: Article
• Language: English
• Subjects: Charge transfer; Color; Electron paramagnetic resonance; Electron spin; Electron transfer; Nanoclusters; Photochromism; Photoelectrons; Photoluminescence; Radiation; Soft x rays; Space charge; Spin resonance; X ray irradiation; X ray photoelectron spectroscopy; X-rays
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/d3nr05409h

Materials exhibiting X-ray-induced photochromism have consistently piqued the interest of researchers. Exploring the photochromic properties of such materials is valuable for understanding the structural changes and electron transfer processes that occur under high energy radiation, such as X-ray irradiation. Here, a crystalline silver( i ) nanocluster synthesized from tert -butylacetylene silver was found to have the ability to exhibit color and photoluminescence changes upon exposure to X-ray radiation. The responsive behavior was observed across a wide temperature range of 100-300 K, with the ability to respond particularly well to soft X-rays ( λ > 1 Å) and exhibit light responsiveness to hard X-rays ( λ < 1 Å). By combining experimental findings including X-ray diffraction, X-ray photoelectron spectroscopy, electron spin resonance, etc. with theoretical calculations, we have proposed that X-ray irradiation induces electron transfer from chloride (Cl − ) located in the center of the silver( i ) nanocluster to the surrounding Ag 14 in the skeleton. This represents the first documented example in which electron transfer induced by X-ray excitation has been observed, accompanied by a photochromism process, in silver nanoclusters. This study contributes to our understanding of X-ray-induced photochromism and the electron transfer process in silver cluster compounds. It also provides valuable insights and potential design strategies for applications such as photochromism, photoluminescence color change, and photoenergy conversion. This work reports the first instance of X-ray-induced photochromism in core-shell silver nanoclusters induced by spatial charge transfer between halogen atoms and silver shell.