Improvement in the performance and efficiency on self-deficient CaTiO3: Towards sustainable and affordable new-generation solar cells

Abstract

Thin films of pure and self-deficient calcium titanites i.e., CaTiO3, Ca1-αTi1O3, CaTi1-βO3 and CaTiO3-γ have been deposited on ITO substrate using dip coating method. X-ray diffraction and Scanning electron Microscopy (SEM) analysis confirm the structural and morphology of all deposited thin films. Photocurrent measurement has been done, and it is observed that during the incidence of UV light on the as-prepared device (i.e., in the “ON” state), a significant increase in photocurrent (IUV) at zero voltage was observed in case of O deficient CaTiO3, while in case of Ti and Ca deficient thin films smaller values of photocurrents were seen. Responsivity and detectivity of deposited thin films of all self-deficient CaTiO3 were found to be maximum in the UV region while they also showed smaller contributions in the visible range possibly due to the presence of self-deficiency. The self-deficient sample exhibits lower resistance (higher recombination rate) than the pure sample at low voltage, but at higher voltage, it is almost identical. Furthermore, theoretical calculations have been performed using the first-principles density-functional theory to validate the experimental findings on self-deficient CaTiO3. Incident-photon-to-current efficiency (IPCE) and current density have also been measured for all deficient CaTiO3 samples. Maximum IPCE have been found in the range 25%− 28% for Ti and O deficient samples in the UV range (280–400 nm). We argue that first-principles DFT calculations combined with the experimental measurements on self-deficient CaTiO3 thin films offer a reliable way to enhance the performance of perovskite-based solar devices.