Modelling Interfaces in Thin-Film Photovoltaic Devices

Abstract

Developing effective device architectures for energy technologies—such as solar cells, rechargeable batteries or fuel cells—does not only depend on the performance of a single material, but on the performance of multiple materials working together. A key part of this is understanding the behaviour at the interfaces between these materials. In the context of a solar cell, efficient charge transport across the interface is a pre-requisite for devices with high conversion efficiencies. There are several methods that can be used to simulate interfaces, each with an in-built set of approximations, limitations and length-scales. These methods range from those that consider only composition (e.g. data-driven approaches) to continuum device models (e.g. drift-diffusion models using the Poisson equation) and ab-initio atomistic models (developed using e.g. density functional theory). Here we present an introduction to interface models at various levels of theory, highlighting the capabilities and limitations of each. In addition, we discuss several of the various physical and chemical processes at a heterojunction interface, highlighting the complex nature of the problem and the challenges it presents for theory and simulation.

Modeling of Magnetic Films: A Scientific Perspective

“…Quantum mechanical models, rooted in the foundational principles of physics, offer unparalleled accuracy in characterizing the behavior of individual electrons and their intricate interplay [ 10 ]. This precision is paramount for capturing nuances in magnetic interactions within films, encompassing attributes such as spin orientations, exchange interactions, and magnetic anisotropy [ 11 ]. Quantum mechanical frameworks provide a microscopic lens to fathom the underlying quantum states and electron distributions that underlie magnetic properties.…”

“…Quantum mechanical frameworks provide a microscopic lens to fathom the underlying quantum states and electron distributions that underlie magnetic properties. This understanding extends to phenomena like magnetism switching, domain wall movement, and magnetic hysteresis, fostering deeper comprehension [ 11 ]. The predictive capability of quantum mechanical simulations guides the design and exploration of novel materials and configurations.…”

“…ϕ(|R i -R j |) is pair potential. The electron density created by the j-th atom at the location of the i-th atom (10)(11)(12). The BOMD method is highly accurate and effective in describing the properties of materials such as dielectrics and metals [21].…”

The role of interface energetics in Sb2Se3 thin film solar cells

“…These efforts are essential for maximizing solar cells' overall performance and efficiency. In a typical solar cell hetero-structure, an absorber layer is situated between two selective charge extraction layers [4,5]. These extraction layers are specifically designed to facilitate the collection of holes and electrons.…”

“…The different energy levels indicated exist independently before the materials come into contact. Not only Sb 2 Se 3 , but other thin-film solar cells, such as CIGS, CdTe, CZTS [1][2][3][4][5] and other inorganic devices, typically have a structure consisting of a metal back contact (BC), an absorber layer (p-type), a buffer layer (n-type), and window layer. The interfaces formed at the metal/absorber and absorber/buffer become critical components of the device and must be effectively passivated [9].…”