Efficient hysteresis-less bilayer type CH sub(3)NH sub(3)PbI sub(3 ) perovskite hybrid solar cells

Bilayer type CH sub(3)NH sub(3)PbI sub(3 ) (MAPbI sub(3)) perovskite hybrid solar cells were fabricated via a one-step spin-coating process by using solubility controlled MAPbI sub(3) solutions of MAPbI sub(3)-DMSO (dimethyl sulfoxide) and MAPbI sub(3)-DMF (N, N-dimethylformamide)-HI. The best DMSO-bilayer device showed 1.07 + or - 0.02 V V sub(oc) (open-circuit voltage), 20.2 + or - 0.1 mA cm super(-2) J sub(sc) (short-circuit current density), 68 + or - 2% FF (fill factor), and 15.2 + or - 0.3% [eta] (overall power conversion efficiency) under the forward scan direction and 1.07 + or - 0.02 V V sub(oc), 20.4 + or - 0.1 mA cm super(-2) J sub(sc), 70 + or - 3% FF, and 15.9 + or - 0.4% [eta] under the reverse scan direction. The best HI-bilayer device had 1.08 + or - 0.02 V V sub(oc), 20.6 + or - 0.1 mA cm super(-2) J sub(sc), 75 + or - 1% FF, and 17.2 + or - 0.2% [eta] under the forward scan direction and 1.08 + or - 0.02 V V sub(oc), 20.6 + or - 0.1 mA cm super(-2) J sub(sc), 76 + or - 2% FF, and 17.4 + or - 0.3% [eta] under the reverse scan direction. The deviation of average device efficiency ([eta] sub(avg)) of 20 DMSO samples and 20 HI samples was 14.2 + or - 0.95% and 16.2 + or - 0.85%, respectively. Therefore, the HI-bilayer devices exhibited better device efficiency and smaller J-V (current density-voltage) hysteresis with respect to the scan direction than the DMSO-bilayer devices due to the reduced recombination and traps by the formation of a purer and larger MAPbI sub(3) perovskite crystalline film.