A modified sequential deposition method for fabrication of perovskite solar cells

In this paper, the important role of perovskites capping layers in the compact-TiO2/mesoporous-TiO2/CH3NH3PbI3/HTM/Au solar cells was investigated. The capping layers were prepared by controlling the concentration of PbI2 solutions, pre-coating in CH3NH3I solution, the reaction temperature, and the dipping time in the sequential deposition process. The results of X-ray diffraction (XRD) spectra revealed that there was no PbI2 remains observed in the perovskite crystal structure, indicating that PbI2 was converted into CH3NH3PbI3 completely. The morphologies of the capping layers are studied by scanning electron microscopy (SEM). Furthermore, organic-inorganic hybrid perovskite solar cells fabricated using the continuous and compact perovskite capping layers exhibit power conversion efficiency of 12.9% and photocurrents up to 19.4 mA cm(-2). (C) 2016 Elsevier Ltd. All rights reserved.