@article{oai:tsukuba.repo.nii.ac.jp:00043766,
 author = {鈴木, 義和 and Okamoto, Yuji and Suzuki, Yoshikazu},
 journal = {Materials science in semiconductor processing},
 month = {Nov},
 note = {CH3NH3PbI3 films prepared by the 2-step method for perovskite solar cells generally have problems of residual unreacted PbI2 and rough surface structure. Here, we report a new 3-step method, based on the 2-step method with an additional spin-coating of CH3NH3(I,Br) solution on the CH3NH3PbI3 film to scavenge remnant PbI2. The 3-step method improved light absorption of the film by converting the residual PbI2 into CH3NH3PbI3−xBrx. Morphological improvements such as a network formation among perovskite grains and a decrease of intergranular voids were also observed. The additional CH3NH3I spin-coating resulted in the increases of both JSC and VOC, while that of CH3NH3Br solution showed a slight decrease of JSC and large increase of VOC due to the enlarged bandgaps. The maximum power conversion efficiency was improved from 12.9% (2-step) to 14.4% (3-step). Furthermore, the 3-step cells retained ~ 85% of the original PCE values after storing in air for 700 h, which indicates an improved stability.},
 pages = {1--6},
 title = {Perovskite solar cells prepared by a new 3-step method including a PbI 2  scavenging step},
 volume = {71},
 year = {2017}
}