An annealing-free aqueous-processed anatase TiO₂ compact layer for efficient planar heterojunction perovskite solar cells

Abstract

A facile aqueous-based fabrication scheme is developed for producing annealing-free anatase TiO (AF-TiO) films that exhibit efficient electron transport properties in planar heterojunction perovskite solar cells (PSCs). AF-TiO films are fabricated by spin coating on a substrate a colloidal solution of anatase TiO nanoparticles (NPs) prepared via a low temperature hydrolytic sol-gel method. The resultant AF-TiO films show low electrical resistance, high transmittance in the visible and near-infrared regions and facilitation of high-quality perovskite film formation, which can be attributed to their homogeneous surface morphology and nanocrystallinity. The AF-TiO based PSCs achieve a power conversion efficiency (PCE) of 18.29 ± 0.18%, showing significant improvement compared to the control PSCs (PCE = 11.33 ± 0.32%) based on TiO films made by high-temperature annealing of amorphous TiO (HTA-TiO).

Fully Air‐Processed Carbon‐Based Efficient Hole Conductor Free Planar Heterojunction Perovskite Solar Cells With High Reproducibility and Stability

“…Figure d is the X‐ray diffraction (XRD) spectra of FTO, FTO/TiO 2 , and FTO/TiO 2 /CH 3 NH 3 PbI 3 films. From XRD results, we can find the appearance of a small peak at around 25°, indicating the presence of TiO 2 , the same as reported . For perovskite layer, there is a small PbI 2 peak, and this will be beneficial for PVSCs since the presence of PbI 2 can help passivate grain boundaries and reduce charge traps inside the crystals …”

Room‐Temperature‐Processed Fullerene/TiO2 Nanocomposite Electron Transporting Layer for High‐Efficiency Rigid and Flexible Planar Perovskite Solar Cells

“…[ 14,15 ] Many groups used nonhydrolytic sol–gel techniques to process low‐temperature TiO 2 ETLs. [ 16–21 ] The highest efficiency, >18%, was recently achieved for a flexible PSC. [ 22–25 ] A low‐temperature‐processed TiO 2 ETL mainly comprises TiO 2 NPs; therefore, surfactants or other insulating materials are required to avoid aggregation and enhance the interconnection of TiO 2 NPs.…”

High‐Performance Flexible Perovskite Solar Cells with Effective Interfacial Optimization Processed at Low Temperatures

“…[1][2][3][4][5][6] Improvements in efficiency,f lexibility,a nd manufacturing temperature have received considerable research attention. As low electron transport will cause serious charger ecombination at the interface between ETL and perovskite, [9][10][11][12][13] which causes efficiency loss and increases the currentd ensity-voltage (J-V)h ysteresis in PSCs. As low electron transport will cause serious charger ecombination at the interface between ETL and perovskite, [9][10][11][12][13] which causes efficiency loss and increases the currentd ensity-voltage (J-V)h ysteresis in PSCs.…”

“…However,m ost high-efficiency PSCs requireh igh-temperature ( % 500 8C) fabrication processes to prepare TiO 2 electron-transport layers (ETLs);T iO 2 prepared at low temperatures can have many defects, such as oxygen vacancies, [7,8] and it is very difficultt os atisfy the requirements fore fficient electron transport. As low electron transport will cause serious charger ecombination at the interface between ETL and perovskite, [9][10][11][12][13] which causes efficiency loss and increases the currentd ensity-voltage (J-V)h ysteresis in PSCs. [14][15][16][17] As such, there are many methodst om odify TiO 2 by doping or by optimizing the TiO 2 morphologya nd/orc omposition, including surfacem odification of TiO 2 through treatments with TiCl 4 or O 3 and doping of TiO 2 with an appropriate substituent of Li + ,s uch as Mg 2 + ,Y 3 + ,a nd Nb 5 + .…”