(Invited) Controlling the Electronic Energy Structure of ZnSe-AgInSe_2 Solid Solution Nanorods for Visible-Light-Driven Photocatalytic H_2 Evolution

摘要

Intense research efforts have been focused on developing high-quality semiconductor nanocrystals (NCs) containing no toxic elements. Especially I-III-VI_2 ternary NCs, such as CuInS_2 and AgInS_2, exhibiting the quantum size effect, have attracted much attention for the application to solar energy conversion systems, because they have large absorption coefficients in the visible wavelength region and their electronic energy structure could be controlled by modifying their size, shape, and chemical composition. Recently we have successfully prepared anisotropic-shaped NCs of ZnS-AgInS_2 solid solution. Their photocatalytic H_2 evolution activity could be controlled by the chemical composition as well as by the particle size, and increased with particle morphology in the order of rice < sphere < rod. To efficiently utilize solar light for photocatalytic reactions, near-IR-responsive NCs have been intensively developed. In general, the E_g of I-III-VI semiconductor decreases with use of Se as group IV element in place of S. Thus, in this study, we prepare rod-shaped NCs composed of less-toxic ZnSe-AgInSe_2 solid solution ((AgIn)_xZn_(2(1-x))Se_2, ZAISe(x)) and report their photocatalytic activity for H_2 evolution.