Optical Simulations in Perovskite Devices: A Critical Analysis

Abstract

With halide perovskite gaining popularity for optoelectronics application, it is imperative to push for device stacks with minimum optical losses and maximum efficiency. However, the vast plethora of material systems and device architectures available through computerized combinatorial analysis made experimental trials for each proposed possibility impractical. Thus, high-throughput optical simulations in conjunction to comprehensive electronic modeling are necessary to predict outputs and minimize experimental efforts involved. Here, we aim to critically summarize some of the most intuitive and efficient approaches to optical modeling for perovskite-based devices and work toward a consensus on the best avenues to utilize these models. First, the nuances of ellipsometry measurements for ascertaining accurate optical constants of perovskite are discussed. Modeling techniques (such as ray tracing, transfer matrices, finite difference time domain, and finite element methods) to simulate the optical interaction within the device are then elaborated focusing on their advantages and limitations. Next, the primary challenges to attaining greater accuracy of optical constant data as well as insights on the future trends are identified. Finally, an interactive flowchart-based decision tree to ascertain the best simulation technique for a given optoelectronic device architecture is built, which will greatly help experimental scientists and beginners in optical modeling.

Modeling of Charge Injection, Recombination, and Diffusion in Complete Perovskite Solar Cells on Short Time Scales

“…The approximation of an exponential decay of the absorption profile given by Equation (11) might not be sufficient if the perovskite thickness is smaller and/or the excitation wavelength is longer (smaller α values) than those used in our studies. Then, all excitation light will not be absorbed within the perovskite layer and additional effects due to light reflection at opposite interface and light interference should be taken into account, e.g., using transfer matrix methods [41,42]. The mixed halide perovskite that we used in our studies might also suffer from photoinduced ion migration that can be a source of additional cation-mediated recombination and affect the charge transfer kinetics and hysteresis of the cells [43,44].…”

A Study on Contact Resistance as a Function of Surface Treatment in Perovskite Field-Effect Transistors

“…Chemical reactions at metal/perovskite interfaces are quite common, even in the case of noble metals, and their impact on the performance and stability of devices can be catastrophic . The halogen, halide, and other volatile species generated in the presence of humidity, oxygen, and/or light even in encapsulated films can diffuse to the electrodes, leaving behind vacancies in the perovskite layer, causing the corrosion of the metal and, in some cases, the formation of redox couples with the perovskite. ,− The metal particles have also been found to diffuse into the perovskite film under heat and/or light and react to produce metal halide species or other defect states. , The electrochemical reactions between the gold electrodes and mobile halogen species are accelerated under external biasing and the introduction of different buffer layers has been proposed to prevent these reactions. ,,, The reduction in the injection barrier due to the intrinsic SAM dipoles and the inhibition of the interfacial reactions contribute to the lowering of the contact resistance in FETs with PFBT-treated contacts, as observed in Figure b, but separating between the two is difficult at the moment. Nevertheless, it is evident that the use of SAMs for contact modifications could play a pivotal role in the development of perovskite applications given the reduced complexity of the fabrication process and the fact that they allow great tunability of the electrode work function.…”

Effects of MgF2 anti-reflection coating on optical losses in metal halide perovskite solar cells

“…TMM is one of the most widely implemented methods for conducting optical simulations, particularly for planar-structured solar cells consisting of multiple thin films [54]. It is generally adopted to easily compute the light propagation aspect within PSCs because of its simplicity in considering multilayers as one-dimensional stacks and has been implemented in numerous studies [38][39][40][41][42][43][44].…”

“…The J SC increment seems to converge near a thickness of 650 nm, which fits the actual perovskite thickness in this work, verified through cross-sectional FE-SEM measurements (figure S7). However, as TMM simulations only consider the optical interaction inside the perovskite and between adjacent layers, external factors such as recombination dynamics and charge transport should be examined via electrical models to conduct more pragmatic simulations [54].…”