Low Temperature Fabrication for High Performance Flexible CsPbI₂Br Perovskite Solar Cells

Abstract

All‐inorganic CsPbX3‐based perovskites, such as CsPbI2Br, show much better thermal and illumination stability than their organic–inorganic hybrid counterparts. However, fabrication of high‐quality CsPbI2Br perovskite film normally requires annealing at a high temperature (>250 °C) that is not compatible with the plastic substrate. In this work, a Lewis base adduct‐promoted growth process that makes it possible to fabricate high quality CsPbI2Br perovskite films at low temperature is promoted. The mechanism is attributed to synthesized dimethyl sulfoxide (DMSO) adducts which allow a low activation energy route to form CsPbI2Br perovskite films during the thermal annealing treatment. A power conversion efficiency (PCE) of 13.54% is achieved. As far as it is known, this is the highest efficiency for the CsPbI2Br solar cells fabricated at low temperature (120 °C). In addition, the method enables fabrication of flexible CsPbI2Br PSCs with PCE as high as 11.73%. Surprisingly, the bare devices without any encapsulation maintain 70% of their original PCEs after being stored in ambient air for 700 h. This work provides an approach for preparing other high performance CsPbX3‐based perovskite solar cells (PSCs) at low temperature, particularly for flexible ones.

Simultaneous Cesium and Acetate Coalloying Improves Efficiency and Stability of FA0.85MA0.15PbI3 Perovskite Solar Cell with an Efficiency of 21.95%

“…The TRPL spectra (Figure b) of the perovskite films were measured and fitted with a double exponential decay function, and the deduced parameters of PL lifetime are listed in Table S1, Supporting Information. The perovskite film with CsAc showed a much longer average carrier lifetime ( τ ave : 61.5 ns) compared with that of the perovskite film without CsAc alloying ( τ ave : 28.9 ns); the increased lifetime is benefit from the improved crystallinity and the reduced trap‐assisted recombination for perovskite film with CsAc alloying …”

All‐Inorganic CsPbX3 Perovskite Solar Cells: Progress and Prospects

“…More interestingly,using this technique,aPCE of 13.5 %and 1.18 V V OC were achieved at low annealing temperature (120 8 8C), and enables fabrication of flexible PSCs with PCE of 11.7 %. [175] Zai et al used DMSO/DMF solvent mixtures at 100 8 8C(using SnO 2 as ETL and PTAA as the HTL) to obtain asPCE of 14.3 %with 1.16 V V OC . [176]…”

Novel Surface Passivation for Stable FA0.85MA0.15PbI3 Perovskite Solar Cells with 21.6% Efficiency

“…The curves were fitted with a biexponential decay function, and the fitting parameters are summarized in Table S1, Supporting Information. The fitted results indicate a longer average carrier lifetime ( τ ave , 50.44 ns) for the perovskite film w TPFPB passivation than for the control film ( τ ave , 44.55 ns), which is attributed to reduced trap‐assisted recombination at defect sites . In addition, PL and TRPL characterizations were also conducted to study the charge‐extraction dynamics at the perovskite/Spiro‐OMeTAD interface.…”