title: Highly Reproducible Perovskite Solar Cells with Average Efficiency of 18.3% and Best Efficiency of 19.7% Fabricated via Lewis Base Adduct of Lead(II) Iodide.
abstract: High efficiency perovskite solar cells were fabricated reproducibly via Lewis base adduct of lead(II) iodide. PbI2 was dissolved in N,N-dimethyformamide with equimolar N,N-dimethyl sulfoxide (DMSO) and CH3NH3I. Stretching vibration of S═O appeared at 1045 cm(-1) for bare DMSO, which was shifted to 1020 and 1015 cm(-1) upon reacting DMSO with PbI2 and PbI2 + CH3NH3I, respectively, indicative of forming the adduct of PbI2·DMSO and CH3NH3I·PbI2·DMSO due to interaction between Lewis base DMSO and/or iodide (I(-)) and Lewis acid PbI2. Spin-coating of a DMF solution containing PbI2, CH3NH3I, and DMSO (1:1:1 mol %) formed a transparent adduct film, which was converted to a dark brown film upon heating at low temperature of 65 °C for 1 min due to removal of the volatile DMSO from the adduct. The adduct-induced CH3NH3PbI3 exhibited high charge extraction characteristics with hole mobility as high as 3.9 × 10(-3) cm(2)/(V s) and slow recombination rate. Average power conversion efficiency (PCE) of 18.3% was achieved from 41 cells and the best PCE of 19.7% was attained via adduct approach.
authors.affiliation: †Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea.
authors.forename: Namyoung
authors.initials: N
authors.lastname: Ahn
authors.affiliation: ‡School of Chemical Engineering and Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: Dae-Yong
authors.initials: DY
authors.lastname: Son
authors.affiliation: ‡School of Chemical Engineering and Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: In-Hyuk
authors.initials: IH
authors.lastname: Jang
authors.affiliation: †Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea.
authors.forename: Seong Min
authors.initials: SM
authors.lastname: Kang
authors.affiliation: †Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea.
authors.forename: Mansoo
authors.initials: M
authors.lastname: Choi
authors.affiliation: ‡School of Chemical Engineering and Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: Nam-Gyu
authors.initials: NG
authors.lastname: Park