Selective degradation of chemical bonds in single precursor molecule toward one pot synthesis of Ag2S quantum dots

INOR 542

Hee Cheul Choi, choihc@postech.edu and Qun Tang, tangqun@postech.ac.kr. Department of Chemistry, Pohang University of Science and Technology, San31, Hyoja-Dong, Nam-Gu, Pohang, 790-784, South Korea
Selective formation of metallic Ag and semiconducting Ag2S nanocrystals has been achieved via a modified hot-injection process from a single-source precursor molecule, Ag(SCOPh) which can potentially generate both [Ag] and [AgS] fragments simultaneously. When the precursor molecules are injected into a preheated reaction system at 160 oC, spherical Ag2S nanocrystals are directly obtained even without a molecular activator, such as alkylamines. Mixtures of Ag and Ag2S or pure metallic Ag nanocrystals are obtained if the precursor molecules are injected at lower or room temperature. These results are attributed to the direct transfer of thermal energies to precursor molecules, which are enough to dissociate S-C as well as Ag-S bonds simultaneously. Such synthetic strategy has been further applied for the facile formation of Ag2S nanocrystal thin films on solid substrates, which are fabricated into three-electrode transistor type devices. As one of the potential applications, highly responsive optoelectric phenomena from Ag2S device has been demonstrated.