Improvement in the Performance and Efficiency on Self-Deficient CaTiO$_3$: Towards Sustainable and Affordable New-Generation Solar Cells

TL;DR

This study explores how creating self-deficient CaTiO3 thin films improves their UV photoresponse and efficiency, combining experimental deposition and characterization with first-principles calculations to advance sustainable solar cell materials.

Contribution

It introduces a novel combination of experimental and theoretical approaches to enhance CaTiO3's performance for solar energy applications through self-deficiency engineering.

Findings

Self-deficient CaTiO3 shows increased photocurrent under UV light.

Maximum IPCE of 25-28% achieved in Ti and O deficient samples.

Self-deficiency reduces resistance at low voltage, improving photoresponse.

Abstract

Thin films of pure and self-deficient calcium titanites i.e., CaTiO$_3$, Ca$_{1-\alpha}$TiO$_3$, CaTi$_{1-\beta}$O$_3$ and CaTiO$_{3-\gamma}$ 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 CaTiO$_3$, 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 CaTiO$_3$. Incident-photon-to-current efficiency (IPCE) and current density have also been measured for all deficient CaTiO$_3$ 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 CaTiO$_3$ thin films offer a reliable way to enhance the performance of perovskite-based solar devices.