Nanostructured SrZrTiO${}_2$ xerogel films for efficient perovskite solar cell applications

The present research comes up with a single-step approach for the preparation of SrZrTiO${}_2$ xerogel films as an electron transport layer for fabricating efficient perovskite solar cells (PSCs). This film is made up of uniform with the average diameter of around 200 nm. Each sphere is composed of 20 nm TiO${}_2$ particles co-doped with Sr${}^{2+}$ and Zr${}^{4+}$. X-ray photoelectron spectroscopy and X-ray diffraction demonstrated that there are no distinct strontium and zirconium compositions created during the film deposition process and the percentage of the introduced ions into the TiO${}_2$ lattice affects its crystallographic characteristics and band gap. A champion PSC based on a xerogel film containing Sr and Zr dopants with the atomic percent of 0.075 and 0.6, respectively, had the maximum performance of 18.73% compared to the reference cell (i.e., 9.18%). This improvement is ascribed to lower series resistance (i.e., 9.95 $\Omega$), charge recombination resistance (i.e., 1194.02 $\Omega$), and electron lifetime (i.e., 23.83 $\mu$s) of the champion cell, as evidenced by electrochemical impedance spectroscopy. Incorporating both alkaline-earth metals and transition metals into titania xerogel films presents an innovative approach to developing high-performance PSCs.