Concentrations Influence of Complexing Agents on the Physicochemical Properties of Chemical Bath Deposited n‐Type FeS_xO_y for Homostructure Solar Cell

A chemical bath deposition (CBD) is applied to deposit n‐type iron sulfide (FeS_xO_y) film on fluorine (F)‐doped tin oxide (SnO₂)–FTO substrate. The duration, temperature, and magnetic stirrer's speed in CBD are 3 h, 75 °C, and 100 revolutions per minute. The influence of complexing agents’ concentration (≤200 mm)–acid (tartaric and lactic) on the physicochemical properties of film is studied. All films are n‐type semiconductors with large bandgap (2.95–3.58 eV) and contain high oxygen (≈56–83%). Scanning electron microscopy image shows the 50 mm tartaric acid film has a uniform and denser surface morphology. FeS_xO_y film with tartaric acid has lesser goethite and hematite peaks in X‐ray diffraction than lactic acid. The FeS_xO_y film with 100 mm lactic acid exhibits a slightly higher transmittance at ≈350–450 nm. The FeS_xO_y homostructure reveals average open‐circuit voltage (V_oc) = 0.45 V, short‐circuit current (J_sc) = 0.0003 mA cm⁻², fill factor =38%, and efficiency (η) = 0.57%.