Fig. 1: Characterization of CdS/Ta2O5 buffer layers.

a Reaction schematic and XRD pattern of Ta2O5 (The inset shows the precursor solution of Ta2O5). b, e Scanning electron microscopy (SEM) images, c, f atomic force microscopy (AFM) mappings, and d hydrophilicity measurements of CdS and CdS/Ta2O5 films. g I–V characteristics of FTO/CdS/Au and FTO/CdS/Ta2O5/Au devices for conductivity evaluation.