Abstract
Tetragonal chalcopyrite CuIn-(S 1-x Se x ) 2 (0 ≤ x ≤ 1) nanocrystals were synthesized by reacting a mixture of CuCl, InCl 3 , S, and Se in the presence of oleylamine at 265 °C. The S/Se composition ratio in the CuIn(S 1-x Se x ) 2 could be tuned across the entire composition range of x from 0 to 1 by modulating the S/Se reactant mole ratio. The tetragonal lattice constants, that is, a and c, increase linearly with the increase of Se content, following Vegard's law. The band gap energies of CuIn(S 1-x Se x ) 2 nanocrystals could be tuned in the range between 0.98 and 1.46 eV and change nonlinearly with respect to x, deriving a bowing parameter of 0.17 eV. In addition, the method developed in this study was scalable to achieve gram-scale production of stoichiometry-controlled CuIn(S 1-x Se x ) 2 and CuIn 1-x Ga x Se 2 nanocrystals. © 2011 American Chemical Society.