This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record . Please cite this article as doi: 10.1002/ente.201901196 This article is protected by copyright. All rights reserved Insights into Recombination Processes from Light Intensity-Dependent Open-Circuit Voltages and Ideality Factors in Planar Perovskite Solar Cells Non Thongprong 1,2∗ , Thidarat Supasai 3 , Youyong Li 4 , I-Ming Tang 5 and Nopporn Rujisamphan 1,2 1 Nanoscience and Nanotechnology Graduate Program, Faculty of Science, King Mongkut’s University of Technology Thonburi, Bangkok, 10140, Thailand 2 Theoretical and Computational Science Center (TaCS), Faculty of Science, King Mongkut’s University of Technology Thonburi, Bangkok, 10140, Thailand 3 Department of Materials Science, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand 4 Institute of Functional Nano and Soft Materials, Soochow University, Suzhou, 215123, Jiangsu Province, China 5 Computational & Applied Science for Smart Innovation Cluster, Faculty of Science, King Mongkut’s University of Technology, Thonburi, Bangkok 10400, Thailand Corresponding E-mail: n.thongprong@gmail.com (Non Thongprong) Keywords: perovskite solar cells, ideality factors, drift-diffusion modeling, diode currents, carrier recombination ABSTRACT To analyze the dominant recombination, researchers often consider the diode ideality factor (nid), determined from the fitting of a semi -log plot of light intensity-dependent open-circuit voltage (Voc(lnI/I0)) to a linear dependence. This value is called ‘ nid,Voc.’ Theoretically, nid is the exponential dependence factor in the recombination rate function of the split of quasi -Fermi levels. This nid is called ‘nid,C.’ In this work, we reconsidered the correlations between nid,Voc, nid,C, and the dominant recombination using a validated numerical drift -diffusion model and a diode current analysis in perovskite solar cell devices having accumulations of charged defects near the carrier transporting interfaces. We found that the interplay between the recombination ongprong gprong 1, n Rujisamp n Rujisam ence and ce and Nan N ’s University ’s Univers ical and Com cal and Co ’s University Un ment of Mater nt of Ma hailand ailand of Function of Fun rovince, Chin e, C ational & App ngkut’s Unive ngkut’s Un nding E ing E- -mai m s: perovskite perovsk combination mbinati CT e the domina the dom rmined from ined fro Voc (lnI/I lnI/I0 0)) to )) al dependenc al depe is nid is called s call