@article{oai:oist.repo.nii.ac.jp:00001154,
 author = {Wang, Yong and Dar, M. Ibrahim and Ono, Luis K. and Zhang, Taiyang and Kan, Miao and Li, Yawen and Zhang, Lijun and Wang, Xingtao and Yang, Yingguo and Gao, Xingyu and Qi, Yabing and Grätzel, Michael and Zhao, Yixin},
 issue = {6453},
 journal = {Science},
 month = {Aug},
 note = {Although beta-CsPbI3 has a bandgap favorable for application in tandem solar cells, depositing and stabilizing beta-CsPbI3 experimentally has remained a challenge. We obtained highly crystalline beta-CsPbI3 films with an extended spectral response and enhanced phase stability. Synchrotron-based x-ray scattering revealed the presence of highly oriented beta-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 beta-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 degrees C ambient conditions.},
 pages = {591--595},
 title = {Thermodynamically stabilized β-CsPbI3–based perovskite solar cells with efficiencies >18%},
 volume = {365},
 year = {2019}
}