Optik - International Journal for Light and Electron Optics 227 (2021) 166061 Available online 23 November 2020 0030-4026/© 2020 Elsevier GmbH. All rights reserved. Original research article Effect of interface defects on high effcient perovskite solar cells Farhad Izadi a , Arash Ghobadi b , Abdolrasoul Gharaati a, *, Mehran Minbashi c, *, Ali Hajjiah d a Department of Physics, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran b Politecnico di Milano, Department of Physics, Piazza Leonardo da Vinci 32, 20133 Milano, Italy c Tarbiat Modares University, Department of Physics, P.O. Box 14115-175, Tehran, Iran d Department of Electrical Engineering, College of Engineering and Petroleum, Kuwait University, Safat 13133, Kuwait A R T I C L E INFO Keywords: Perovskite Voc and FF Interface defect Offset ABSTRACT In this paper, experimental J–V and external quantum effciency (EQE) have been validated by the simulation model to show the improvement of the perovskite (PSK) solar cell (PSC) effciency. The effect of interface properties at the electron transport layer (ETL) /PSK and PSK/hole transport layer (HTL) were examined with Solar Cell Capacitance Simulator (SCAPS). The in- terfaces between ETL/PSK/HTL were known as important factors for determining high open- circuit voltage (Voc) and FF. In this study, the impact of two kinds of interfaces, i.e., ETL/PSK and PSK/HTL, were examined. When the interface defect density at both interfaces decrease to 10 2 cm 2 , the interface recombination became low, and Voc and FF increased. In contrast, when the trap defect energy at interfaces increased near to the bandgap of the PSK, the collection of photo-generated carriers was enhanced due to the formation of better offset for electron current fow. Thus, the optimum trap defect energy was 1.4 eV for both interfaces. Also, the capture cross- section for both electron and hole (σ n and σ p ) was 10 -20 cm 2 . These results will be useful for new material choice and optimization of ETLs and HTLs. 1. Introduction Renewable resources are very reliable, plentiful, and important for energy production because of diminishing fossil fuel sources (such as coal and petroleum) by considering some environmental limitations such as required costly explorations, and potentially dangerous mining and drilling [1–6]. One of their notable energy production lies in solar cell manufacturing [4,7,8]. Organ- ic–inorganic hybrid perovskites of the form AMX 3 that are contained of a monovalent cation, A = cesium (Cs + ), methylammonium (MA); formamidinium (FA); a divalent metal M = (Pb 2+ ; Sn 2+ ); and a halide anion X = (Cl  , Br  ; I  ) has emerged as one of the most promising low-cost absorbers for solar cells [9–11]. Material properties of perovskite such as high absorption coeffcient, long carrier diffusion lengths (in the μm-range), fexible bandgap, and defect endurance. These caused an increment in the power conversion effciency (PCE) of PSCs up to 25.5 % [12]. Moreover, a large number of techniques such as spin coating, dip coating, 2-step inter- diffusion, vacuum-assisted evaporation can be used for deposition of perovskite materials [13]. The perovskite damages at high temperatures; but the point is that, most of the mentioned techniques are solution-based and low temperature compatible (<100 ̊ C). All of these properties promote the low-cost commercialization of PSCs. The highest reported effciencies have been achieved with * Corresponding author. E-mail addresses: farhad.izadi@gmail.com (F. Izadi), agharaati@pnu.ac.ir (A. Gharaati), mehran.minbashi@modares.ac.ir (M. Minbashi). Contents lists available at ScienceDirect Optik journal homepage: www.elsevier.com/locate/ijleo https://doi.org/10.1016/j.ijleo.2020.166061 Received 21 August 2020; Received in revised form 28 October 2020; Accepted 22 November 2020