Fabricating inorganic–organic hybrid perovskite solar cells (PSCs) on plastic substrates broadens their scope for implementation in real systems by imparting portability, conformability and allowing high-throughput production, which is necessary for lowering costs. Here we report a new route to prepare highly dispersed Zn2SnO4 (ZSO) nanoparticles at low-temperature (<100 °C) for the development of high-performance flexible PSCs. The introduction of the ZSO film significantly improves transmittance of flexible polyethylene naphthalate/indium-doped tin oxide (PEN/ITO)-coated substrate from ∼75 to ∼90% over the entire range of wavelengths. The best performing flexible PSC, based on the ZSO and CH3NH3PbI3 layer, exhibits steady-state power conversion efficiency (PCE) of 14.85% under AM 1.5G 100 mW·cm−2 illumination. This renders ZSO a promising candidate as electron-conducting electrode for the highly efficient flexible PSC applications.

Ternary oxides are potential candidates as an electron-transporting material that can replace TiO₂ in dye-sensitized solar cells (DSSCs), as their electronic/optical properties can be easily controlled by manipulating the composition and/or by doping. Here, we report a new highly efficient DSSC using perovskite BaSnO₃ (BSO) nanoparticles. In addition, the effects of a TiCl₄ treatment on the physical, chemical, and photovoltaic properties of the BSO-based DSSCs are investigated. The TiCl₄ treatment was found to form an ultrathin TiO₂ layer on the BSO surface, the thickness of which increases with the treatment time. The formation of the TiO₂ shell layer improved the charge-collection efficiency by enhancing the charge transport and suppressing the charge recombination. It was also found that the TiCl₄ treatment significantly reduces the amount of surface OH species, resulting in reduced dye adsorption and reduced light-harvesting efficiency. The trade-off effect between the charge-collection and light-harvesting efficiencies resulted in the highest quantum efficiency (i.e., short-circuit photocurrent density), leading to the highest conversion efficiency of 5.5% after a TiCl₄ treatment of 3 min (cf. 4.5% for bare BSO). The conversion efficiency could be increased further to 6.2% by increasing the thickness of the BSO film, which is one of the highest efficiencies from non-TiO₂-based DSSCs.

BaSnO3 is designed as an electron transport layer of high-efficiency perovskite and dye-sensitized solar cells by fine-tuning energy levels through substitution of specific amounts of Sr ions.

Among ternary oxides, Zn2 SnO4 (ZSO) is considered for dye-sensitized solar cells (DSSCs) because of its wide bandgap, high optical transmittance, and high electrical conductivity. However, ZSO-based DSSCs have a poor performance record owing largely to the absence of systematic efforts to enhance their performance. Herein, general strategies are proposed to improve the performance of ZSO-based DSSCs involving interfacial engineering/modification of the photoanode. A conformal ZSO thin film (blocking layer) deposited at the fluorine-doped tin oxide-electrolyte interface by pulsed laser deposition suppressed the back-electron transfer effectively while maintaining a high optical transmittance, which resulted in a 22 % improvement in the short-circuit photocurrent density. Surface modification of ZSO nanoparticles (NPs) resulted in an ultrathin ZnO shell layer, a 9 % improvement in the open-circuit voltage, and a 4 % improvement in the fill factor because of the reduced electron recombination at the ZSO NPs-electrolyte interface. The ZSO-based DSSCs exhibited a faster charge injection and electron transport than their TiO2 -based counterparts, and their superior properties were not inhibited by the ZnO shell layer, which indicates their feasibility for highly efficient DSSCs. Each interfacial engineering strategy could be applied to the ZSO-based DSSC independently to lead to an improved conversion efficiency of 6 %, a very high conversion efficiency for a non-TiO2 based DSSC.

We report TiO2nanobranches/nanoparticles (NBN) hybrid architectures that can be synthesized by a facile solution phase method. The hybrid architecture simultaneously improves light harvesting and charge collection performances for a dye-sensitized solar cell. First, TiO2nanorods with a trunk length of 2 μm were grown on a fluorine-doped tin oxide (FTO)/glass substrate, and then nanobranches and nanoparticles were deposited on the nanorods’ trunks through a solution method using an aqueous TiCl3solution at 80°C. The relative amount of nanobranches and nanoparticles can be controlled by multiplying the number of TiCl3treatments to maximize the amount of surface area. We found that the resultant TiO2NBN hybrid architecture greatly improves the amount of dye adsorption (five times compared to bare nanorods) due to the enhanced surface area, while maintaining a fast charge collection, leading to a three times higher current density and thus tripling the maximum power conversion efficiency for a dye-sensitized solar cell.