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Thermodynamically stabilized β-CsPbI 3 –based perovskite solar cells with efficiencies >18%

2019; American Association for the Advancement of Science; Volume: 365; Issue: 6453 Linguagem: Inglês

10.1126/science.aav8680

1095-9203

Yong Wang, M. Ibrahim Dar, Luis K. Ono, Taiyang Zhang, Miao Kan, Yawen Li, Lijun Zhang, Xingtao Wang, Yingguo Yang, Xingyu Gao, Yabing Qi, Michaël Grätzel, Yixin Zhao,

Quantum Dots Synthesis And Properties

Although β-CsPbI3 has a bandgap favorable for application in tandem solar cells, depositing and stabilizing β-CsPbI3 experimentally has remained a challenge. We obtained highly crystalline β-CsPbI3 films with an extended spectral response and enhanced phase stability. Synchrotron-based x-ray scattering revealed the presence of highly oriented β-CsPbI3 grains, and sensitive elemental analyses-including inductively coupled plasma mass spectrometry and time-of-flight secondary ion mass spectrometry-confirmed their all-inorganic composition. We further mitigated the effects of cracks and pinholes in the perovskite layer by surface treating with choline iodide, which increased the charge-carrier lifetime and improved the energy-level alignment between the β-CsPbI3 absorber layer and carrier-selective contacts. The perovskite solar cells made from the treated material have highly reproducible and stable efficiencies reaching 18.4% under 45 ± 5°C ambient conditions.