Room-Temperature-Processed Amorphous Sn-In-O Electron Transport Layer for Perovskite Solar Cells

Abstract

We report amorphous tin-indium-oxide (TIO, Sn fraction: >50 atomic percentage (at%)) thin films as a new electron transport layer (ETL) of perovskite solar cells (PSCs). TIO thin films with Sn fraction of 52, 77, 83, 92, and 100 at% were grown on crystalline indium-tin-oxide (ITO, Sn fraction: ~10 at%) thin films, a common transparent conducting oxide, by co-sputtering In2O3 and SnO2 at room temperature. The energy band structures of the amorphous TIO thin films were determined from the optical absorbance and the ultraviolet photoelectron spectra. All the examined compositions are characterized by a conduction band edge lying between that of ITO and that of perovskite (here, methylammonium lead triiodide), indicating that TIO is a potentially viable ETL of PSCs. The photovoltaic characteristics of the TIO-based PSCs were evaluated. Owing mainly to the highest fill factor and open circuit voltage, the optimal power conversion efficiency was obtained for the 77 at%-Sn TIO ETL with TiCl4 treatment. The fill factor and the open circuit voltage changes with varying the Sn fraction, despite similar conduction band edges. We attribute these differences to the considerable changes in the electrical resistivity of the TIO ETL. This would have a significant effect on the shunt and/or the series resistances. The TIO ETL can be continuously grown on an ITO TCO in a chamber, as ITO and TIO are composed of identical elements, which would help to reduce production time and costs.

Effect of Optimization of TiO2 Electron Transport Layer on Performance of Perovskite Solar Cells with Rough FTO Substrates

“…It is generally known that charge recombination is highly responsible for reducing the energy conversion efficiency of PSCs. Many researchers have focused on the ETL of PSCs [16,17,27]. Some investigators have tried to add a new layer into the ETL to form a bilayer, which has been demonstrated as an effective way to modify the interfacial behavior and photovoltaic performance of PSCs.…”

A comprehensive review on the advancements and challenges in perovskite solar cell technology

“…The produced ZSO nanoparticle-based PSCs exhibited a PCE of 15.3%. 122 Subsequently, a solution-processed ZSO-lm was employed by Jung et al 123,124 as an ETL in a PSC, resulting in a record-breaking efficiency of 20.02%. Recently, Zheng et al 125 created a Zn 2 SnO 4 single crystal using a straightforward, affordable hydro-thermal synthesis process.…”