Pilkington's FTO TEC 15 substrates were first cut into 1×2.5 cm 2 pieces and then meticulously cleaned using a series of solvents: soapy distilled water, distilled water, acetone, and isopropyl alcohol (IPA). Following this cleaning process, they were dried with a nitrogen gun. Subsequently, the substrates underwent a 30 minute UV/ozone cleaning to eliminate surface contaminants. Next, a Safematic CCU-010 sputter coater was employed to apply a 10 nm thick layer of titanium (Ti) (acting as an adhesion layer) followed by a 150 nm thick layer of gold (Au) onto the FTO substrates (serving as a hole-extracting electrode, creating an ohmic contact with the photoabsorber). A threeelectrode setup was utilized to carry out the electrodeposition of antimony (Sb) metal onto the FTO/Ti/Au substrates. The Sb electrodeposition solution consisted of 15 mM potassium antimony tartrate and 50 mM tartaric acid, with the pH adjusted to 1.3. An electrode potential of -0.3 V versus Ag/AgCl was applied to control the Sb thickness by monitoring the charge passed, limited to 1.4 C cm -2 . Careful attention was given to ensure uniform thickness and optimal performance during deposition. Subsequently, the resulting Sb substrates underwent a selenization process using a two-zone furnace. Selenium pellets were positioned around the substrate, and the chamber was purged with argon. The temperature was gradually increased to 350 °C at a rate of 15 °C per minute and held for 40 minutes. For the reference, Sb2Se3/Pt samples, a 2 nm thick platinum (Pt) layer was sputtered onto the photocathode. This method creates high-quality compact thin films without requiring advanced high vacuum equipment. However, it is crucial to exercise caution to prevent minor gas leaks that could lead to forming an Sb2O3 layer on top of the Sb2Se3.