Visible-light induced photosplitting of water using solution-processed Cu2BaSnS4 photoelectrodes and a tandem approach for development of Pt-free photoelectrochemical cell

In this present work, investigation on the physical and chemical properties of the quaternary Cop-per-barium-thiostannate (Cu2BaSnS4) compound was carried out. Cu2BaSnS4(CBTS) thin films were synthesized by using the cost-effective, sol-gel spin-coating technique without further sulfurization. The light-sensitive nature of CBTS was investigated by illuminating the thin films directly under AM 1.5G condition, resulting in an enhancement of 47% in terms of photocurrent density. The p-type nature was confirmed from the Mott Schottky analysis carried out in 0.5 M Na2S solution without illumination. A flat band potential value of 2.354 +/- 0.003 V vs. RHE along with a carrier density of 9.314 x 10(19) cm(-3) and Debye length of 0.288 nm were also obtained for the CBTS thin films. From Bode plots, the carrier lifetime of CBTS films was estimated to be 88 m s. Further Pt free photoelectrochemical cells were fabricated by using ZnO nanorods as counter electrodes. From linear sweep voltammetry results, photocurrent density of 6.805 and 2.112 mA/cm(2) at 0 V (vs. RHE) under illumination in the presence of Pt electrodes and ZnO Nanorods, respectively. Photoconversion efficiency of similar to 10% and similar to 4% were estimated for the CBTS thin film in the presence of Pt and ZnO counter electrodes. Thus the physical properties observed here indicate the suitability of solution-processed CBTS thin films in its further use for harvesting solar energy.

Automated summary

The physical and chemical properties of quaternary copper-barium-thiostannate (Cu2BaSnS4) compound were investigated in this study. Cu2BaSnS4 (CBTS) thin films were synthesized using a cost-effective sol-gel spin-coating technique, revealing a significant enhancement in photocurrent density under AM 1.5G condition. The p-type nature of CBTS was confirmed, and its suitability for harvesting solar energy was demonstrated through the fabrication of Pt free photoelectrochemical cells with ZnO nanorods as counter electrodes.