Photoelectrochemical characterization of n-type and p-type thin-film nanocrystalline Cu2ZnSnSe4 photocathodes

Copper-zinc-tin-selenide (Cu2ZnSnSe4, CZTSe) nanocrystals that do not contain any toxic elements and are 20-25nm in size are synthesized through a process involving reactions of the elemental sources in a polyetheramine solution. By controlling the Zn/Sn ratio, both n-type and p-type CZTSe nanocrystals could be synthesized. The photoelectrochemical (PEC) properties of electrodes formed using inks containing n-type and p-type CZTSe nanocrystals are compared. An aqueous solution of NaCl is used as the electrolyte. A PEC cell based on an n-type CZTSe photoanode exhibits an efficiency, eta(c,) of 2.81%, while a p-type cell exhibits hc of 0.42%. The flat band potentials of the n-type and p-type CZTSe photoanodes in 1M NaCl are -0.55 and 0.48V, respectively. Finally, the net carrier concentrations of the n-type and p-type CZTSe photoanodes, calculated from their Mott-Schottky plots, are 3.38 x 10(18) and 2.73 x 10(18)cm (3), respectively. a 2014 Elsevier Ltd. All rights reserved.