Photoelectrochemical performance of aluminum-doped AgIn5S8 electrodes created using chemical bath deposition

A solution growth method for the deposition of Al-doped silver-indium-sulfide film electrodes is presented. Structural, optical, and photoelectrochemical (PEC) properties of samples were studied as a function of Al content. An X-ray diffraction pattern of the cubic spinel AgIn5S8 phase was obtained for the undoped sample. No Al alloys or other binary compounds that included the Al element were present in Al-doped samples. Images from a scanning electron microscope and atomic ratios of elements in samples from the energy dispersion analysis of X-ray revealed a change of surface morphology and composition for Al-doped samples. The direct band gaps and thicknesses of samples prepared in this study varied from 1.78 to 1.90 eV and from 391 to 293 nm, respectively. The carrier concentration and mobility of samples determined from Hall measurements are in the ranges of 1.02 × 1013–1.97 × 1014 cm− 3 and 16–75 cm2/Vs, respectively. The maximum photo-enhancement current density of samples reached 3.22 mA/cm2 at an external potential of + 1.0 V vs. an Ag/AgCl reference electrode in an aqueous solution containing S2− and SO32− ions under illumination using a 300 W Xe lamp system. The experimental results show that Al doping improves the performance of AgIn5S8 photo-absorber for the PEC applications with an Al/(Al + In) molar ratio of 0.03 in samples.