Well-dispersed, size-tunable chalcopyrite CuInSe2 nanocrystals and its ink-coated thin films by polyhydric solution chemical process

Single-phase, near-stoichiometry and well-dispersed chalcopyrite CuInSe2 nanocrystals were synthesized by a facile, ambient pressure solution chemical route using triethylene glycol as solvent, copper(II) chloride, indium(III) chloride and selenium powder as precursors. Crystallization, morphology, chemical stoichiometry and light property of the synthesized nanocrystals were characterized. Size dependence of the nanocrystals on different alkaline conditions, respectively adding sodium hydroxide, triethanolamine and ethylenediamine into reaction solutions was investigated. The synthesized nanocrystals were used to prepare ethanol-based colloidal inks and then deposit flat, dense and (112) oriented chalcopyrite thin films by layer-by-layer ink-dip-coating method and annealing at 550 °C in Ar. I–V characteristics of the PV devices with the ink-coated CuInSe2 light-absorbing layer were measured.

► Well-dispersed CuInSe2 nanoparticles were synthesized by TEG based solution route.
► Nanoparticle size can be changed by alkaline condition in synthesis process.
► CuInSe2 thin films with (112) orientation were formed by nanoparticles ink coating.
► Fill factor and energy conversion efficiency reached 35% and 0.11%, respectively.