Annealing‐Free Cr₂O₃ Electron‐Selective Layer for Efficient Hybrid Perovskite Solar Cells

Abstract

The electron-selective layer (ESL) plays a pivotal role in the performance of perovskite solar cells (PSCs). In this study, amorphous dispersible chromium oxide (Cr O ) nanosheets are synthesized by a facile solvothermal reaction, and a Cr O ESL is prepared by spin-coating Cr O ink on fluorine-doped tin oxide substrates without need for further annealing. By using Cr O as the electron-selective layer and Cs (MA FA ) Pb(I Br ) as the light-absorption layer, a planar hybrid perovskite solar cell is fabricated. The spin-coating speed is optimized, the structure and morphology of samples are observed, the photoelectrical properties of ESLs are characterized, and the photovoltaic behaviors of devices are measured. Results show that the as-prepared Cr O layer has high optical transmittance and superb electron extraction and carrier transport property. The planar hybrid PSC based on the optimized Cr O ESL achieves a power conversion efficiency of 16.23 %, which is comparable to devices based on a conventional high-temperature-calcined TiO ESL. These results demonstrate a low-cost and facile route to highly effective perovskite solar cells.

Enhanced Crystallization by Methanol Additive in Antisolvent for Achieving High‐Quality MAPbI3 Perovskite Films in Humid Atmosphere

“…[1] Besides the remarkable photovoltaic performance, the antisolvent-assisted one-step spin-coating crystallization methodi so ne of the widely used methodst op repareh igh-quality perovskite films. Typically used antisolvents are diethyle ther, [3] toluene, [4] chlorobenzene, [5] and ethyl acetate, [6] which have low boilingp oints, weak electron-donating capability,a nd poor coordination ability with perovskite precursors.T he week coordination of the antisolvents can modify the balance between the reduction of grain boundaries and the adjustment of the perovskite films. The perovskite intermediate phase is formed when the antisolvent is dropped during the spin-coating process where the evaporation rate of the solventd etermines the film thickness after which the solution becomes supersaturated, leadingt on ucleation and finally crystal growth.…”

“…The antisolvent is responsible for controlling the morphology of the perovskite material by inducing fast precipitation of the perovskite, resulting in highly dense and smooth perovskite films. Typically used antisolvents are diethyle ther, [3] toluene, [4] chlorobenzene, [5] and ethyl acetate, [6] which have low boilingp oints, weak electron-donating capability,a nd poor coordination ability with perovskite precursors.T he week coordination of the antisolvents can modify the balance between the reduction of grain boundaries and the adjustment of the perovskite films. [7] Therefore, it is important to study the effect of the antisolvent in coordinating perovskite crystal growth and film formation as the choice of the antisolvent affects the overall morphologya nd hence the optoelectronic performance of the perovskite layer.I na ddition, the fabrication process of PSCs is usually performed inside anitrogen/argon-filled glovebox to avoid moisture, as the perovskite layer can degrade easily in ambient humidity.…”

Simple, Robust, and Going More Efficient: Recent Advance on Electron Transport Layer‐Free Perovskite Solar Cells

“…In the work by Wang and co-workers, ETL-free device with PCE of 12.89% was demonstrated, while the PCE of the aminosubstituted perylene diimide (N-PDI)/FTO based device gave a highest PCE of 17.66% ( Figure S1h, Supporting Information). [71] The planar PSC based on the optimized Cr 2 O 3 ETL gains a highest PCE of 16.23%, which is higher than that of the ETL-free device ( Figure S2b, Supporting Information). [61] Masood et al studied the effect of film thickness of dip-coated compact TiO 2 layers on the performance of mesoscopic PSCs.…”

“…The highest PCE of the ETL‐free PSC was 6.3%, when inserting a compact TiO 2 layer the PCE was promoted up to 9.0%. Huang and co‐workers reported efficient PSCs with annealing‐free Cr 2 O 3 as ETL . The planar PSC based on the optimized Cr 2 O 3 ETL gains a highest PCE of 16.23%, which is higher than that of the ETL‐free device (Figure S2b, Supporting Information).…”

To Be Higher and Stronger—Metal Oxide Electron Transport Materials for Perovskite Solar Cells

“…Very recently, n‐type Cr 2 O 3 with proper energy band level and outstanding stability has been used as a promising ETL for planar PSCs . They obtained a best PCE of 16.23% comparable to that of TiO 2 based devices.…”