Excellent photoelectric properties entail perovskite solar cells with established position prevailing in the newgeneration photovoltaic landscape. However, the traditional solution preparation inevitably yields numerous defects, which eventually bloom ion migration and lead to the gradual collapse of perovskite. Here, phthalic acid (PHA) with adjacent carboxylic acid groups (−COOH) is used to passivate defects and regulate the morphology of perovskite films. Based on density functional theory (DFT) calculations, the two adjacent −COOH of PHA construct a dual interaction with the uncoordinated Pb 2+ of perovskite, thus significantly enhancing the passivation effect. Furthermore, the double-bonding interaction brought by PHA induces a unique surface-protruding morphology on perovskite films, which may act as a green channel for charge delivery, ultimately increasing the photo-generated current of perovskite solar cells (PSCs) to some extent. Under full-air preparation conditions, the PHA-optimized champion PSCs showed an efficiency of 20.02% with a boosted short-circuit current of 22.80 mA cm −2 , showing one of the best performances in all-air preparation until now. Meanwhile, PHA-PSCs exhibited brilliant stability. In short, this work provides some reliable and flexible guidance for the design of small-molecule additives.
The two-step deposited method with the advantages of high reproducibility and controllability is widely used in fabricating highly efficient perovskite solar cells (PSCs). However, it is still a challenge to fabricate air-processed PSCs through this method due to the existing techniques with glove box circumstance that are not well extended to the ambient air-condition fabrication process. Here, hexamethylphosphoramide (HMPA) used as a solvent additive is incorporated into the first-step PbI 2 precursor solution, which can effectively modify the morphology and crystallinity of the PbI 2 layer, thereby creating more opportunities for the infiltration of the secondstep organic salt. This two-step coating leads to the full conversion from PbI 2 to the perovskite crystal and large grains, reduced defects, and enhanced uniformity for the final perovskite film. Consequently, a champion efficiency of 20.84% of the HMPA-based device fabricated using this procedure is achieved. The HMPA-based device shows long-term stability of the remaining 85.7% of the initial efficiency after 1000 h of storage in an ambient air environment. This method demonstrates the great potential toward air-processed efficient PSCs.
To achieve future commercialization of perovskite solar
cells (PSCs),
balancing the efficiency, stability, and manufacturing cost is required.
In this study, we develop an air processing strategy for efficient
and stable PSCs based on 2D/3D heterostructures. The organic halide
salt phenethylammonium iodide is adopted to in situ construct a 2D/3D
perovskite heterostructure, in which 2,2,2-trifluoroethanol as a precursor
solvent is introduced to recrystallize 3D perovskite and form an intermixed
2D/3D perovskite phase. This strategy simultaneously passivates defects,
reduces nonradiative recombination, prevents carrier quenching, and
improves carrier transport. As a result, a champion power conversion
efficiency of 20.86% is obtained for air-processed PSCs based on 2D/3D
heterostructures. Moreover, the optimized devices exhibit superior
stability, remaining more than 91 and 88% of their initial efficiencies
after 1800 h of storage under dark condition and 24 h of continuous
heating at 100 °C, respectively. Our study provides a convenient
method to fabricate all-air-processed PSCs with high efficiency and
stability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.