RESUMO
Fabricating perovskite solar cells (PSCs) in air is conducive to low-cost commercial production; nevertheless, it is rather difficult to achieve comparable device performance as that in an inert atmosphere because of the poor moisture toleration of perovskite materials. Here, the perovskite crystallization process is systematically studied using two-step sequential solution deposition in an inert atmosphere (glovebox) and air. It is found that moisture can stabilize solvation intermediates and prevent their conversion into perovskite crystals. To address this issue, thermal radiation is used to accelerate perovskite crystallization for integrated perovskite films within 10 s in air. The as-formed perovskite films are compact, highly oriented with giant grain size, superior photoelectric properties, and low trap density. When the films are applied to PSC devices, a champion power conversion efficiency (PCE) of 20.8% is obtained, one of the best results for air-processed inverted PSCs under high relative humidity (60 ± 10%). This work substantially assists understanding and modulation to perovskite crystallization kinetics under heavy humidity. Also, the ultrafast conversion strategy by thermal radiation provides unprecedented opportunities to manufacture high-quality perovskite films for low-temperature, eco-friendly, and air-processed efficient inverted PSCs.
RESUMO
Three iridium(III)-based metal-organic frameworks (MOFs), namely [Cd3{Ir(ppy-COO)3}2(DMF)2(H2O)4]·6H2O·2DMF (1), [Cd3{Ir(ppy-COO)3}2(DMA)2(H2O)2]·0.5H2O·2DMA (2), and [Cd3{Ir(ppy-COO)3}2(DEF)2(H2O)2]·8H2O·2DEF (3) (ppy-COOH = methyl-3-(pyridin-2-yl)benzoic acid, DMF = N,N-dimethylformamide, DMA = N,N-dimethylacetamide, DEF = N,N-diethylformamide), have been synthesized and characterized. Single-crystal structural determinations reveal that compounds 1-3 are isostructural, showing a three-dimensional framework structure with (3,6) connected rtl topologyin whose trimers of {Cd3(COO)6} are cross-linked by Ir(ppy-COO)33-. The structures are completely different from those of other Ir(III)-based MOFs. Compound 1 was selected for a detailed study on sensing properties. The excellent luminescence as well as good water stability of 1 makes it a highly selective and sensitive multiresponsive luminescent sensor for Fe3+ and Cr2O72-. The detection limits are 67.8 and 145.1 ppb, respectively. Compound 1 can also be used as an optical sensor for selective sensing of adenosine triphosphate (ATP2-) over adenosine diphosphate (ADP2-) and adenosine monophosphate (AMP2-) in aqueous solution. This is the first example of iridium(III)-based MOFs for the optical detection of Fe3+, Cr2O72-, and ATP2-. More interestingly, the luminescent composite film doped with 1% (w/w) of compound 1, 1@PMMA (PMMA = poly(methyl methacrylate)), can be successfully prepared, which endows efficient sensitivity for Fe3+ and Cr2O72- detection and thus provides great potential for future applications.