Solution‐Processed Wafer‐Scale Ag2S Thin Films: Synthesis and Excellent Charge Transport Properties

Abstract

AbstractMonoclinic α‐Ag2S is an intriguing member of transition metal sulfides with great potential for all‐inorganic flexible optoelectronics and thermoelectrics. Fabrication of large‐area, high‐quality α‐Ag2S thin films and understanding their charge transport properties are critical for device operations yet have remained largely unexplored. Here, a novel two‐step, the solution‐processed approach is reported to produce wafer‐sized, highly crystalline α‐Ag2S thin films. Ultrafast terahertz (THz) conductivity measurements reveal that photogenerated charge carriers undergo efficient band transport, with room‐temperature mobility of ≈150 cm2 V‐1 s‐1 and a diffusion length exceeding 500 nm. Furthermore, introducing poly(vinyl alcohol) (PVA) as the rigid component into the aqueous silver thiolate precursor enables the synthesis of free‐standing α‐Ag2S thin films with a mobility of ≈35 cm2 V‐1 s‐1, demonstrating their potential for flexible optoelectronics. This study provides a facile synthesis route for high‐quality, large‐area α‐Ag2S thin films with good charge transport properties, relevant for their integration into optoelectronics and wearable electronics.