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Air-stable hybrid perovskite solar cell by sequential vapor deposition in a single reactor
摘要： Here we demonstrate a facile two-step low-pressure vapor deposition of methyl-ammonium lead iodide (MAPbI3) perovskite films in a single reactor. Continuous, poly-crystalline lead iodide (PbI2) films were deposited in the first step and successfully converted to high quality perovskite films in the second step during exposure of PbI2 films to methyl-ammonium iodide (MAI) vapor. A complete conversion was realized after 90 minutes of exposure with an average grain size of 3.70 ± 1.80 μm. The perovskite conversion starts at the PbI2 surface through the intercalation reaction of PbI2 and MAI vapor molecules and progresses towards the PbI2/substrate interface. The coverage and quality of the perovskite thin film is controlled by that of the pre-deposited PbI2 film. The absorbance measurements confirmed air stability of the fully converted perovskite for 21 days, ascribed to its superior morphology and grain size. Finally, a planar single-junction perovskite solar cell with no additives or additional interfacial engineering was fabricated and tested under open-air conditions, yielding a best power conversion efficiency of 11.7%. The solar cell maintains 85% of its performance up to 13 days in open-air with relative humidity up to 80%.
关键词： planar device,Two-step vapor deposition,large grains,intercalation,air-stable
更新于2025-09-23 15:19:57
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Thioacetamide additive assisted crystallization of solution-processed perovskite films for high performance planar heterojunction solar cells
摘要： High-quality perovskite films with uniform coverage and large grains are indispensable to enhance the performance of perovskite solar cells with high efficiency and stability. However, solution-processed perovskite films usually possess small grains associated with abundant grain boundaries, which induce high trap state density and then seriously degrade the device performance. In this paper, the volatile Lewis base, thioacetamide (TAA), is employed as an additive to fabricate high-quality methylammonium lead iodide (MAPbI3) films. The average grain size of perovskite films increases continuously with increasing TAA content and reaches a maximum value of 960 nm in the sample with 1.0% TAA. However, the average gain size drops dramatically to the value of samples without TAA when TAA content increases to 2.0%, and then the average gain size keeps nearly unchanged upon further increasing TAA content up to 10%. This unusual grain size variation tendency is attributed to the volatility of additive, and a mechanism is proposed based on various characterizations to illustrate how volatile TAA improves perovskite film crystallization. Furthermore, the device based on the MAPbI3 film with 1.0% TAA shows a superior PCE of 18.9% and improved stability that the device with 1.0% TAA retains 88.9% of its initial performance after aging 816 h in the air with 25–35% relative humidity. The results strongly suggest that the TAA-modified MAPbI3 films as absorber layers can significantly enhance the performance of the perovskite solar cell due to large grains, high crystallization and reduced trap state density of the high quality TAA-modified MAPbI3 films.
关键词： Perovskite solar cells,Thioacetamide,Large grains,Lewis base,Thin film growth
更新于2025-09-19 17:13:59