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Increased luminescent efficiency of perovskite light emitting diodes based on modified two-step deposition method providing gradient concentration
摘要： We increased the luminescent efficiency of perovskite light-emitting diodes (PeLEDs) by using a modified two-step deposition method combined with an interdiffusion process without additional solvent engineering or additive molecules. Methylammonium lead bromide (MAPbBr3) polycrystalline films with nanosized grains and low electronic disorder were fabricated by a modified two-step deposition process. The as-fabricated MAPbBr3 films showed gradient concentration characteristics as a result of a gradient distribution of the MABr. Also, the MABr-gradient concentration structure was intensified by the interdiffusion process, showing improved performance of MAPbBr3 PeLEDs with maximum current efficiency CEmax = 0.861 cd A?1 and maximum luminance = 604 cd m?2 with very narrow electroluminescence spectral width. This is the highest CEmax among MAPbBr3-based PeLEDs deposited by the two-step deposition method.
关键词： two-step deposition method,perovskite light-emitting diodes,luminescent efficiency,gradient concentration,interdiffusion process
更新于2025-09-23 15:21:21
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The role of moisture in the preparation for efficient planar perovskite solar cells
摘要： Perovskite solar cells (PSC) have achieved a certificated efficiency of 25.2% within the past few years. Among effective methods, one of the most effective approaches obtaining highly-efficient PSCs is the moisture-assisted annealing process. However, the role of moisture in the preparation of high-performance PSCs is under intense debate. Herein the critical effect of moisture in the preparation of efficient Formamidinium (FA) based PSCs with improved-quality perovskite films is systematically investigated based on diverse characterizations. Consequently, the optimal amount of moisture is determined at 50% relative humidity (RH) which produces perovskite films of higher quality with larger and uniform grains size in comparison to the control films prepared in the glovebox. Specifically, prolonged lifetime, reduced defects densities and higher light harvesting capability of perovskite films annealed in 50RH% are confirmed by the photoluminescence (PL), the time-resolved PL (TRPL), the space charge limited current (SCLC) and the confocal laser scanning microscopy (CLSM), respectively. These results indicate the environments with a controlled level of moisture is preferable for achieving high-quality perovskite films and the compatibility of fabricating highly-efficient PSCs under ambient conditions with controlled moisture for future industrial mass production.
关键词： defects density,two-step deposition,Planar perovskite solar cells,moisture,space-charge-limited current
更新于2025-09-16 10:30:52
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Tetrahydrofuran as an Oxygen Donor Additive to Enhance Stability and Reproducibility of Perovskite Solar Cells Fabricated in High Relative Humidity (50%) Atmosphere
摘要： In sequential deposition method of lead-halide perovskite material, the PbI2 layer morphology plays an essential role in enhancing the power conversion efficiency (PCE) of the perovskite solar cell. However, humidity level affects the PbI2 and perovskite film morphology, resulting in defect sites and recombination centers on the surface and within the bulk of the perovskite solar cell. To address this, we report the incorporation of tetrahydrofuran (THF) additive in PbI2-DMF precursor solution, to improve the quality of PbI2 thin film and to prevent the water interaction directly with PbI2 under high humidity environment. The O-donor THF interacts with PbI2 resulting in the homogeneous, dense and pinhole-free layer as compared to PbI2 layer without additive. The Perovskite layer so obtained from pinhole-free PbI2 layer is compact and smooth resulting in a significant reduction of defects/traps. The device fabricated with modified perovskite ~ 50% humidity atmosphere, resulted in 15% efficiency with high reproducibility. Moreover, the THF modified non-encapsulated perovskite device retains its 80% PCE after exposing to 50% relative humidity for 20 days. Our result demonstrates the strategy to fabricate perovskite solar cells with reproducible efficiency in high humidity atmosphere viable for large-scale production.
关键词： two-step deposition,perovskite solar cells,high humidity,long-term stability,pinhole-free PbI2,tetrahydrofuran (THF)
更新于2025-09-11 14:15:04