Deciphering the role of (Er3+/Nd3+) co-doping effect on TiO2 as an improved electron transport layer in perovskite solar cells

Abstract

Charge injection and transport at the interface of the electron transport layer (ETL) and perovskite interface are crucial for the perovskite solar cell (PSC) device performance. Titanium dioxide (TiO2) is well established as a photoanode in numerous solar energy conversion and storage. The bandgap engineering of TiO2 by Rare-Earth (RE)-doping has become a significant way to improve the optoelectronic device performance. This study demonstrates the improved performance of Rare-Earth doped TiO2 (RETO) photoanode based solar cells under the doping of Er3+, Nd3+ and following codoping of the (Er3+/Nd3+) effect. It is note that the Er, and Nd dopants are responsible for producing Ti3+ states and the oxygen vacancies near the surface, which drives the charge transportation much more effectively. With the (Er/Nd) codoping into TiO2, the band structure of TiO2 is modified better to make a quasi-Ohmic contact with the perovskites, by fermi level shifting as well changes in the conduction band minima (ECBM) energy states. This results evidence the preliminary conformation for the improvement of Jsc and Voc. Furthermore, the photoluminescence (PL) emission quenching effects of perovskite-deposited RETO attributes the suppression in the charge recombination. By insight into all these favourable results in the(Er3+/Nd3+) codoped TiO2, the RETO photoanode-based perovskite solar cell (PSC) devices were constructed and exhibited improved photovoltaic properties. The composition of (Er0.002Nd0.002Ti0.996O2) ETL employed PSC reported with a better photoconversion efficiency (PCE %) among all the compositions.