Efficient and Thermally Stable Wide Bandgap Perovskite Solar Cells by Dual‐Source Vacuum Deposition

Abstract

Wide bandgap perovskites are being widely studied in view of their potential applications in tandem devices and other semitransparent photovoltaics. Vacuum deposition of perovskite thin films is advantageous as it allows the fabrication of multilayer devices, fine control over thickness and purity, and it can be upscaled to meet production needs. However, the vacuum processing of multicomponent perovskites (typically used to achieve wide bandgaps) is not straightforward, because one needs to simultaneously control several thermal sources during the deposition. Here a simplified dual-source vacuum deposition method to obtain wide bandgap perovskite films is shown. The solar cells obtained with these materials have similar or even larger efficiency as those including multiple A-cations, but are much more thermally stable, up to 3500 h at 85 °C for a perovskite with a bandgap of 1.64 eV. With optimized thickness, record efficiency of >19% and semitransparent devices with stabilized power output in excess of 17% are achieved.

Atomic Layer Deposition-Free Monolithic Perovskite/Perovskite/Silicon Triple-Junction Solar Cells

“…In general, spin-coating processes using nonvolatile polar solvents, such as dimethyl sulfoxide (DMSO) and N,N -dimethyl­formamide (DMF), are used to fabricate highly efficient PVSK films for multijunction devices. , These solvents readily penetrate the interfacial layers between two PVSK films during the second spin-coating process, leading to the partial dissolution of the underneath PVSK layer . It was also reported that the residual nonvolatile solvents still exist in the thin film even after the drying process due to the formation of a PVSK–solvent intermediate phase. , Depositing a dense oxide interlayer via atomic layer deposition (ALD) is a proven way to prevent the degradation of the underneath PVSK layer. − However, the ALD process with a slow growth rate requires a long process time, potentially increasing the fabrication cost and causing damage to the PVSK cell due to the oxidizing agent and the high process temperature. − Another way to avoid the solvent-related degradation of the underneath PVSK layer is to adopt vacuum deposition techniques, , but no study has so far demonstrated the successful vacuum deposition of an upper PVSK layer on another PVSK layer.…”

“…24−26 However, the ALD process with a slow growth rate requires a long process time, potentially increasing the fabrication cost and causing damage to the PVSK cell due to the oxidizing agent and the high process temperature. 27−29 Another way to avoid the solvent-related degradation of the underneath PVSK layer is to adopt vacuum deposition techniques, 30,31 but no study has so far demonstrated the successful vacuum deposition of an upper PVSK layer on another PVSK layer. This study used a novel solvent mixture of acetonitrile (ACN) and methylamine (MA) in ethanol with higher volatility than conventional solvent mixtures to prevent the degradation of the PVSK bottom cell during the processing of another PVSK top cell.…”

Revealing the Hole and Electron Transport Dynamics in the Working Devices for Efficient Semitransparent Perovskite Solar Cells

“…Commercial PERC solar cells with 23.4% efficiency were utilized and the semitransparent/ PERC c‐Si 4T tandem device power output was obtained by PD IEC TS 60904‐1‐2 and the calculation method was provided in supporting information. [ 35 ] In addition to the 23.3% efficiency produced by the ST‐PSCs, the filtered PERC solar cell generated 7.5% efficiency (Figure S17, Supporting Information), totaling the output power is 30.8 mW cm −2 , which is among the highest of the 4‐T perovskite/PERC‐Si tandem solar cells (Table S2, Supporting Information).…”

Close-Space Sublimation as a Scalable Method for Perovskite Solar Cells

“…Interestingly, a short annealing process of 100 °C for 2 min noticeably improved device performance (Figure S7) and may point to the feasibility of shorter annealing times for improving device performance. Despite this, a prolonged annealing at 85 °C was chosen for this study to compare with an existing baseline for thermal stressing of perovskite solar cells in our group . Device stability and performance were tracked for a total of 650 h. In Figure a, the notable increase in PCE occurs over the first 200 h and is reflected in the FF, J sc , and V oc where trend lines have been marked.…”

“…Despite this, a prolonged annealing at 85 °C was chosen for this study to compare with an existing baseline for thermal stressing of perovskite solar cells in our group. 31 Device stability and performance were tracked for a total of 650 h. In Figure 4 a, the notable increase in PCE occurs over the first 200 h and is reflected in the FF, J sc , and V oc where trend lines have been marked. In particular, the V oc improved from 0.8 to 1.04 V over 9 days of thermal stressing.…”