Solution-growth-synthesized Cu(In,Ga)Se₂ nanoparticles in ethanol bath for the applications of dye-sensitized solar cell and photoelectrochemical reaction

In this study, ternary CuInSe₂ and quaternary CuIn_{1 − x}Ga_xSe₂ (CIGSe) nanoparticles (NPs) are grown in the ethanol bath using the one step solution growth method. The influence of Ga content in samples on the optical and electronic properties of the samples is investigated. Average particle sizes of samples are less than 66 nm after a 10-min. reaction in the solution. The NPs are prepared as the ink for the deposition of CIGSe samples on substrates. X-ray diffraction patterns of samples reveal that samples are the chalcopyrite CIGSe phase when the [Ga]/[In+Ga] molar ratio in solution bath of less than 0.5. The carrier concentration and mobility of samples are in the ranges of 1.2 × 10¹³−9.1 × 10¹⁵ cm⁻³ and 1.4–205 cm²/V/s, respectively. The results show that the maximum photo-conversion efficiency of 7.02% for the dye-sensitized solar cells using CIGSe as the counter electrodes and the maximum photoelectrochemical performances of 0.96 mA/cm² at an external bias of −0.8 V vs. an Ag/AgCl electrode using the CIGSe as the photoelectrodes in salt–water solution, respectively.