Different types of PV solar cells have been developed, including first-generation (1G) solar cells based on single-crystalline silicon; second-generation (2G) solar cells based on cadmium telluride (CdTe), copper indium gallium selenide (CIGS) and amorphous silicon; and third-generation (3G) solar cells based on organic solar cells (OSCs), dye-sensitized solar cells (DSSCs), multijunction cells, quantum-dot-sensitized solar cells (QDSCs) and perovskite solar cells (PSCs). The commercial 1G solar cells based on crystalline silicon that are currently dominating the PV market exhibit remarkable stability with a maximum power conversion efficiency (PCE) of about 25% in the lab, but the theoretical limit of the PCE is about 31%. The PCE of 2G solar cells is lower than 1G but they are significantly less expensive than 1G solar cells due to their lower processing cost and materials. Since 1G solar cells made up of nontoxic crystalline silicon have about a 25-year performance warranty and show fairly high PCE with negligible degradation, they are leading the PV solar cell market. Although 1G solar cells exhibit high PCE, they are not free from some fundamental drawbacks such as high manufacturing and installation costs. Although there is a relatively large global demand for silicon solar cells, the device formation at high temperature is very expensive due to the high melting point of silicon, limiting their future development. Therefore, it is crucial to explore new PV materials with high PCE and low production costs to replace or complete the state-of-the-art PV technology for the future development of solar cells. In order to fulfill the gap, scientists have been on a quest to develop 3G solar cells with the aim of high PCE with lower cost. Among all 3G solar cells, perovskite solar cells (PSCs) have recently been attracting much attention and have also emerged as a hot research area of competing materials for silicon PV due to their comparable PCE, easy fabrication, long charge-carrier lifetime, low binding energy, low defect density, and low cost.
Perovskite is a mineral consisting largely of calcium titanate (CaTiO3), which was discovered by the German mineralogist Gustav Rose in the Ural Mountains of Russia in 1839 and named after the Russian mineralogist Lev Aleksevich Perovski. Since then, the term perovskite is generally applied to the class of materials having the same type of crystal structure and stoichiometry as CaTiO3. A perovskite is an organic/inorganic hybrid and possesses a general formula of ABO3, in which A and B stand for cations of rare-earth or alkaline-earth metals and transition metals of 3d, 4d, and 5d configurations, and O stands for oxygen, which bonds to both cations. The ABO3 structure of perovskite is ideally cubic, whereas A atom is bigger than B and forms the corner of cubic cells, coordinated by a 12-fold cuboctahedral, B atoms are in the center and surrounded by an octahedral of anions with 6-fold coordination and the oxygen atom at the centers of the faces of the unit cells. The oxide perovskites show good activity in various fields such as dielectrics, piezoelectrics, photocatalysis, ferroelectrics and pyroelectrics, etc., but are not good for PV applications. Some compounds, like LiNbO3, BiFeO3, and PbTiO3, exhibit some PV activity due to the ferroelectric polarization effect, which makes them suitable for PV applications. However, halide perovskite, a new class of perovskite, differs from oxide perovskite in that it has a halide anion instead of oxide anions with general formula ABX3, presenting the excellent semiconducting properties that are desired for PV solar cells. Moreover, the A is a monovalent metallic cation from group I of the periodic table instead of divalent in the case of oxide perovskite, B is divalent cations that form transition metals instead of tetravalent, and X is the non-metallic anion (halide).
Halide perovskites were discovered in the 1890s, but they were first comprehensively studied by Wells et al. in 1893. Mitzi’s group investigated the physical properties of two-dimensional (2D) halide perovskite materials having organic group in the 1990s. In 2006, the Miyasaka group used perovskites as the first photovoltaic absorber, which provided only 2.2% PCE. After that, the development of PSCs continued to boom and exhibited fast improvement in efficiency to 3.8% in 2009, 6.5% in 2011, 20.1% in 2015, 22.1% in 2017, 24.2% in 2019, and 25.5% in 2020. This fast improvement in the performance of PVCs might have been due to their unique properties such as small bandgap, high dielectric constant, lower excitation binding energies, high absorption coefficient, high charge-carrier mobility and length, and so on.
This book provides a state-of-the-art summary and discussion about the recent progress in the development and engineering of PSCs materials along with the future directions it might take. Moreover, the recent advances in perovskite materials for energy conversion and environmental applications have been compiled herein.
Khursheed Ahmad
Waseem Raza
April 2022
1
Computational Approach for Synthesis of Perovskite Solar Cells
A.S. Mathur* and B.P. Singh
Department of Physics, Institute of Basic Science, Dr. Bhimrao Ambedkar University, Agra (U.P.), India
Abstract
Computational approach has emerged as an effective technique for analyzing the synthesis of novel structures of perovskite solar cells. This approach involves modeling and simulation of solar cells. With respect to solar cells, numerical simulation has proven to be a viable tool over the years to study and comprehend the features and properties of solar cell devices, like the electrical, optical, and mechanical properties of complicated device structures of solar cell. The advantages of simulation are calculating the electrical behavior before the manufacturing process, calculating and visualizing internal electronic values that cannot be measured. It also helps to reduce processing costs and time spent on manufacturing solar cell devices by providing useful information on how the parameters of production can be varied to improvise the behavior of the device. Quantitative modeling of the photovoltaic response of the solar cell is an important subject for improving both the understanding of operation mechanisms and the device performance. In the present chapter, basic steps involved in the modeling of solar cells have been described along with some simulation approaches being used for perovskite solar cells, such as SCAPS-1D, AMPS, ASA, AFORS-HET, and so on. Results of some recent studies have also been presented, elucidating the importance of modeling and simulation approaches in the design and development of perovskite solar cells.
Keywords: Perovskite solar cells, modeling, simulation, photovoltaic parameters
1.1 Introduction
Computational simulation is a technique that uses a software program to research and analyze the behavior of a real device or an imaginary system. Simulation is based on a mathematical model describing the process under study. In many instances of functional interest, numerical simulation of semiconductor devices is an effective tool for chip development. It is a significant technique for optimizing new semiconductor devices.
With