Facile and Robust Solvothermal Synthesis of Nanocrystalline CuInS? Thin Films.

ABSTRACT: This work demonstrates that the solvothermal synthesis of nanocrystalline CuInS? thin films using the amino acid l-cysteine as sulfur source is facile and robust against variation of reaction time and temperature. Synthesis was carried out in a reaction time range of 3?48 h (at 150 °C) and a reaction temperature range of 100?190 °C (for 18 h). It was found that at least a time of 6 h and a temperature of 140 °C is needed to produce pure nanocrystalline CuInS? thin films as proven by X-ray and electron diffraction, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Using UV-vis spectroscopy, a good absorption behavior as well as direct band gaps between 1.46 and 1.55 eV have been determined for all grown films. Only for a reaction time of 3 h and temperatures below 140 °C CuInS? is not formed. This is attributed to the formation of metal ion complexes with l-cysteine and the overall slow assembly of CuInS?. This study reveals that the reaction parameters can be chosen relatively free; the reaction is completely nontoxic and precursors and solvents are rather cheap, which makes this synthesis route interesting for industrial up scaling.

SUBMITTER: Frank A 

PROVIDER: S-EPMC6027332 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature