3‐D Modeling of Ultrathin Solar Cells with Nanostructured Dielectric Passivation: Case Study of Chalcogenide Solar Cells

Abstract

Ultrathin solar cells can be a path forward to low‐cost photovoltaics due to their reduced material consumption and shorter required deposition times. With excellent surface passivation, such devices may feature higher open‐circuit voltages (VOC). However, their short‐circuit current density (JSC) may be reduced due to decreased light absorption. This mandates implementation of efficient light‐trapping structures. To design efficient ultrathin solar cells that combine surface‐passivation and light‐trapping features, accurate 3‐D modeling is necessary. To this end, a novel 3‐D optoelectrical finite‐element model is developed to analyze the performance of ultrathin solar cells. The model is applied to the case of ultrathin (<500 nm) chalcogenide solar cells (copper indium gallium (di) selenide, CIGSe), rear‐passivated with nanostructured Al2O3 to circumvent optical and electrical losses. It is found that such a nanopatterned dielectric passivation scheme enhances broadband light‐trapping with reduced rear‐surface recombination, resulting in an absolute power conversion efficiency enhancement of 3.9%, compared to cells without passivation structure. Overall, the work shows how 3‐D finite element modeling can aid in analyzing and developing new optical and electrical solar cell designs for ultrathin solar cells such as those based on chalcogenides and perovskites.

Temperature-Dependent Optical Modeling of Perovskite Solar Cells

“…Temperature-dependent optical simulations of triple-cation-based PSCs are based on our previous numerical model of the thin-film solar cell. , The device design for the simulation is based on the fabricated device structure of PSCs as shown in Figure S1 in the SI. The optical constants of each layer in the device (except the perovskite absorber) are measured through room temperature ellipsometry measurements and are assumed to be invariant with temperature (see Figure S14 in the SI for further details).…”