Effect of Transition Metal Doping in the ZnO Nanorod on the Efficiency of the Electron Transport Layer in Semitransparent CsPbBr3 Perovskite Solar Cells

We have grown vertically ZnO nanorods (NRs) doped withCu and Nito modulate their electronic properties. The wurtzite structure ofthe ZnO NRs was confirmed from the top-view field emission scanningelectron microscopy (FESEM) and atomic force microscopy (AFM) imagesas well as X-ray diffraction (XRD) spectra, and the phase purity wasconfirmed by Raman spectroscopy. The NRs exhibit high texture orientationin the (002) and (100) directions of the Ni- and Cu-doped ZnO NRs,respectively. This structural modification significantly modulatestheir electronic properties. Scanning tunneling spectroscopy (STS)and corresponding density of states (DOS) measurements were employedto determine the electronic band gap and band-edge shift of the dopedZnO NRs. Ambient-processed semitransparent CsPbBr3 perovskitesolar cells (PSCs) were fabricated with the device structure (FTO/ZnOseed layer/ZnO NRs:CsPbBr3/Spiro-MeOTAD/ITO) using theseNRs as the electron transport layer (ETL). The Ni-doped ZnO NR sampleswere found to be very good in electrical conductivity with a low electronicband gap, which yielded a device power conversion efficiency (PCE)of 4.94% under ambient conditions. Thus, Ni-doped ZnO NRs could beused as an efficient low-cost and ambient-processed one-dimensionalETL in the fabrication of optoelectronic devices.

Automated summary

In this study, vertically aligned ZnO nanorods doped with Cu and Ni were grown to modulate their electronic properties. The wurtzite crystal structure and high purity of the doped nanorods were confirmed through various characterization techniques. The Ni-doped nanorods exhibited a high texture orientation in the (002) direction, while the Cu-doped nanorods showed a texture orientation in the (100) direction. The modification of the structure significantly influenced their electronic properties. Additionally, the Ni-doped ZnO nanorods were utilized as an efficient and low-cost electron transport layer in the fabrication of ambient-processed CsPbBr3 perovskite solar cells, achieving a device power conversion efficiency of 4.94%.