Contents lists available at ScienceDirect Solar Energy journal homepage: www.elsevier.com/locate/solener Impact of fluorine on organic cation for determining the electronic and optical properties of CH 3-x F x NH 3 PbI 3 (x = 0, 1, 2, 3) hybrid perovskites- based photovoltaic devices A. Laref a, ⁎ , M. Al-Enazi a , H.R. Al-Qahtani a , S. Laref b , Xiaozhi Wu c a Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451 Saudi Arabia b Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Str., D-35032 Marburg, Germany c Institute for Structure and Function, Chongqing University, Chongqing 401331, China ARTICLE INFO Keywords: Optical absorption Halide perovskite Photovoltaic devices Fluorine effect Electronic structure ABSTRACT Hybrid halide perovskite CH 3 NH 3 PbI 3 is emerging as a promising solar cell material owing to its low-cost fabrication and remarkable optical and electronic properties. In this scrutiny, we examined the structural sta- bility, electronic structures, and optical properties of a pure cubic MAPbI 3 compound and the CH 3-x F x NH 3 PbI 3 (x = 0, 1, 2, 3) compounds derived by the substitutional impact of fluorine on the methylammonium (MA) organic cation. In our calculations, we employed the full-potential linear augmented plane wave (FP-LAPW) methodology within the generalized gradient approximation (GGA). From the minimization of total energy, the lattice parameter and formation energy of CH 3-x F x NH 3 PbI 3 (x = 0, 1, 2, 3) hybrid perovskites are computed. The results clearly revealed that the pure MAPbI 3 is the most stable perovskite among other structures. The electronic properties determined from the electronic density of states depend quite significantly on the impact of fluorine of MA organic cation and inorganic component, i.e. [PbI 6 ] -4 . The important optical spectra (the complex dielectric function, complex refractive index, absorption coefficient, energy loss function, and re- flectivity) are computed for the halide perovskites (CH 3-x F x NH 3 PbI 3 , x = 0, 1, 2, 3) versus the photon energy. The values of the static dielectric constants and the static refractive index are found to diminish with the in- creasing of the number of fluorine atoms in MA cation. The electronic polarizability was also calculated for all the considered materials in the high frequency optical span. Interestingly, the high absorption coefficient (∼10 6 cm -1 ) and a band gap of around 1.6 eV render these hybrid perovskite materials to be prosperous for photovoltaic applications. For the various physical properties of pure CH 3 NH 3 PbI 3 compound, a good con- sistency is found comparatively to the available experimental and theoretical results. Our findings are expected to be of great interest for future investigations. 1. Introduction Over the past few years, the rapid technological advancements in metal-halide hybrid perovskites (HOPs) have revolutionized the field of photovoltaic (PV) cells with a remarkable increase in their power conversion efficiencies from 3.8 to 22.7% (Xia, 2014; Kim, 2015; Xing, 2014; Green et al., 2014; Kim, 2012; Hao, 2014; Fan et al., 2015; Da Como et al., 2016; Awino et al., 2017; Li, 2008; Sani et al., 2018; Santomauro, 2017). The development is considered to be a break- through in the arena of third-generation PV cells with the HOPs emerging progressively as a promising alternative to the conventional photovoltaic cells (Kim, 2012; Da Como et al., 2016). Intriguingly, the hybrid perovskites are also expected to be incorporated into several other semiconductor devices based on their impressive characteristics such as low trap density of states and high carrier mobility that aid realize PV cells with high quantum efficiency. Accordingly, the poten- tial applications include the solution-processed semiconductor devices such as photodetectors (Xia, 2014), light emitting diodes (LED) (Kim, 2015); and lasers (Xing, 2014). The HOPs are formed basically by re- placing the elemental perovskite building blocks with molecular anions or cations. A perovskite structure has a generic form (ABX 3 ) analogous to its oxide counterpart except for the halide anion in place of oxygen anion. In the case of an organic-inorganic metal halide, A is represented by an organic cation (Green et al., 2014), B is typically represented by a divalent metal ion such as Pb 2 + or Sn 2 + , and X is represented by a halogen ion (I - , Br - , or Cl - )(Fan et al., 2015). In this regard, the https://doi.org/10.1016/j.solener.2018.11.026 Received 3 July 2018; Received in revised form 7 November 2018; Accepted 12 November 2018 ⁎ Corresponding author. E-mail address: alaref@ksu.edu.sa (A. Laref). Solar Energy 177 (2019) 517–530 0038-092X/ © 2018 Elsevier Ltd. All rights reserved. T