Fabrication of p-CuI/n-ZnO heterostructure with a methodical interfacial charge transfer characteristics for photoelectrochemical water splitting

ZnO is a strategical material for an effective Photoelectrochemical water splitting application due to their earth abundance, chemical stability, benignity and notable optical and electrical properties. However, its limited visible light absorption and the tendency of the photogenerated charged pairs to recombine has been challenging for obtaining solar energy conversion. In this work, we have adopted an efficient route to minimize the recombination rate and improve the charge transfer and separation property of ZnO photoanode by forming a heterostructure. CuI nanoparticles loaded ZnO nanorod arrays (CuI/ZnO NRs) were fabricated via a three-step chemical approach (sol-gel and hydrothermal) on conducting ITO/glass substrate. The results indicated that the maximum photocurrent density of about 0.67 mA/cm(2) at 1.23 V vs RHE was recorded for the prepared p-type CuI/n-type ZnO based photoanode which exhibited about six-fold enhancement in photocurrent density as compared to pure ZnO NRs measured under similar conditions. The photoconversion efficiency (PCE%) is about 0.18% for the CuI/ZnO heterostructure. EIS analysis revealed higher donor density (N-d = 6.8 x 10(20) cm(-3)) in the hybrid structure indicating higher carrier concentration. The results obtained reveals new insight for fabricating p-n heterojunction photoelectrodes for an augmented PEC water splitting approach.