Precursor reactivity differentiation for single-step preparation of Ag2Se@Ag2S core–shell nanocrystals with distinct absorption and emission properties enabling sensitive near-infrared photodetection

Autor: Cai Wenhao, Shilin Tang, Chuansheng He, Dong Li, Louzhen Fan, Yunchao Li
Rok vydání: 2018
Předmět:
Zdroj: Journal of Materials Science. 53:11355-11366
ISSN: 1573-4803
0022-2461
Popis: To obtain dual active near-infrared (NIR) nanomaterial with strong absorption and emission properties, we report herein a novel precursor reactivity differentiation strategy, i.e., utilizing 1-octadecene (ODE)–Se having the ability to react with Ag salts much stronger and faster than ODE–thiourea, for single-step preparation of Ag2Se@Ag2S nanocrystals (NCs). With this strategy, we were able to synthesize high-quality Ag2Se@Ag2S NCs with both excellent NIR absorption and emission properties. Particularly, these nanocrystals possess a rather strong and sharp excitonic absorption peak with a full width at half maximum less than 70 nm and a maximum fluorescence quantum yield as high as 24.3%. Their appealing optical properties and structural features were founded to be highly dependent on the Se to S precursor ratio in the reaction solutions, owing to such a ratio exerting a direct influence on the core sizes and shell thicknesses of the as-formed NCs. Taking advantage of their remarkable NIR absorption properties, self-powered photoelectrochemical-type photodetectors based on the as-prepared Ag2Se@Ag2S NCs were successfully fabricated, which demonstrate a much better response performance and photostability in comparison with those based on Ag2Se NCs.
Databáze: OpenAIRE
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