1：Experimental Design and Method Selection:

The Cd1?xMnxSe alloy was prepared using a successive ionic layer adsorption and reaction (SILAR) method. The concentration of Mn dopant was optimized at 20%.

2：0%. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: TiO2 films were deposited onto F-doped SnO2 (FTO) substrates. CdS and Cd1?xMnxSe layers were then deposited onto TiO2 films using SILAR.

3：List of Experimental Equipment and Materials:

Materials included Na2SO3, NaOH, Cd(CH3COO)2.2H2O, Zn(NO3)2, Na2S.9H2O, methanol, TiCl4, and Mn(CH3COO)2.2H2O. Equipment included a JEOL 7500 F high-resolution scanning electron microscope for SEM, Philips model for XRD, JASCO V-670 for absorption spectrum, and electrochemical impedance spectroscopy (EIS) Series G

4：2H2O, Zn(NO3)2, Na2S.9H2O, methanol, TiCl4, and Mn(CH3COO)2H2O. Equipment included a JEOL 7500 F high-resolution scanning electron microscope for SEM, Philips model for XRD, JASCO V-670 for absorption spectrum, and electrochemical impedance spectroscopy (EIS) Series GExperimental Procedures and Operational Workflow:

750. 4. Experimental Procedures and Operational Workflow: The TiO2 paste was deposited onto FTO substrates and sintered. CdS and Cd1?xMnxSe layers were deposited using SILAR. The performance of the solar cells was evaluated using I-V curves and EIS.

5：Data Analysis Methods:

The I-V curves were analyzed to determine dynamic resistances. UV-Vis spectra and time-resolved photoluminescence were used to study optical properties.