E. Ha, H.-W. Man, K.-Y. Wong, L.Y.S. Lee
The Hong Kong Polytechnic University,
Keywords: CZTS, HER, Photocatalysis
Summary:Direct conversion of solar energy into chemical fuels, such as photon-driven water splitting to produce hydrogen gas, is both clean and renewable path thus very attractive solution for energy crysis and pollution problems. A quaternary semiconductor complex Cu2ZnSnS4 (CZTS) is one of the promising candidates for thin film light absorber material in solar energy conversion applications. Its low cost and high performance, as well as optimum band gap energies (~1.5 eV) and high absorption coefficients are comparable to the widely studied chalcopyrite semiconductors, CuIn(1-x)GaxSe2 (CIGS), while they are composed of only earth-abundant and non-toxic elements. Using a simple solution chemestry, we demonstrate the delicate tailoring of the size, shape, and crystallinity of CZTS nanocrystals with a high degree of monodispersity. The CZTS and its analogue Cu2FeSnS4 (CITS) nanostructures were further engaged to construct core/shell nanocomposite using the gold nanoparticle (Au NP) as core. The photocatalytic reduction of water to hydrogen gas using various CZTS and CITS-based nanostructures and their hybrids as photocatalysts will be presented.