Facile fabrication of water-dispersible AgInS2 quantum dots and mesoporous AgInS2 nanospheres with visible photoluminescence

摘要

A facile one-step method for preparing water-dispersible carboxylic acid-terminated AgInS2 quantum dots (QDs) with near-infrared (NIR) emission was developed. In the presence of polyethylenimine, the as-prepared AgInS2 QDs gathered together to form QDs-self-assemblies, followed by centrifugating to obtain QDs aggregates. After that, the resulting QDs aggregates were calcined at elevated temperature to yield AgInS2 nanospheres. Experimental results confirmed that the AgInS2 nanospheres exhibited a mesoporous structure and consisted of repeated units of AgInS2 QDs. The mesoporous AgInS2 nanospheres had photoluminescence (PL) in the visible region that was different from that of the original AgInS2 QDs emitted in the NIR region. High PL stability and low cytotoxicity of the nanospheres were verified experimentally. These results further revealed the potential of mesoporous AgInS2 nanospheres for biomedical application, especially serving as novel nanoprobes for in vitro and in vivo PL imaging.