Importance of Interfacial Passivation in the High Efficiency of Sb₂Se₃ Thin-Film Solar Cells: Numerical Evidence

Abstract

In this paper, we demonstrate numerical evidence that interfacial passivation in the Sb 2 Se 3 solar cell forming the configuration of indium tin oxide (ITO)/SnO 2 /CdS/Sb 2 Se 3 /Au is beneficial for suppressing defects and obtaining cells with high efficiency. First, the effects of two types of defects including bulk defects in the Sb 2 Se 3 absorber layer and interfacial defects at the CdS/Sb 2 Se 3 interface on the performance of solar cells are studied, respectively. It is found that the effect of the bulk defects varied greatly in different magnitudes of defect density, whereas significant deterioration could be caused by the interfacial defect at relatively lower defect density. Then, the types of three actual defects named D1, D2, and D3 measured experimentally in the Sb 2 Se 3 solar cells are analyzed by comparing the simulation and experimental results. It is found that the case D1 and D2 existing in the absorber layer while D3 located at the interface makes the simulation and experimental results the most consistent, in which the interfacial defect D3 contributes the most to the degradation of cell performance. Finally, a SnO 2 -free Sb 2 Se 3 solar cell sample is simulated to evaluate the crucial interfacial passivation effect of the SnO 2 layer. The results show that introducing a SnO 2 layer is beneficial for the passivation of not only the interfacial defects but some unclear mechanisms such as deep-level defects which are hard to be measured in the present experiment. The numerical simulation results provide evidence proving the importance of interfacial passivation in actual fabrication processes to improve the performance of Sb 2 Se 3 solar cells.

Numerical Investigation of Interface Passivation Strategies for Sb2Se3/CdS Solar Cells

“…The results appear very consistent with those from ref. [[10], with interface defects being the main factor limiting the conversion efficiency of the cells, thus validating the consistency of our baseline model with previous reports.…”

“…solar cell parameters used in our model being from in-lab characterizations, though the defect parameters of D1, D2, and D3 are taken similar to ref. [10] to ensure an accurate comparability between both studies. In a first step, we investigate how the surface sulfurization of a bare Sb 2 Se 3 absorber can electrically passivate the Sb 2 (S,Se) 3 /CdS interface, through the creation of a "front surface field."…”

“…[12] specifically reports on the existence of a deep defect at 0.39 eV, with a concentration possibly as high as 10 17 cm −3 . It was additionally demonstrated [ 10 ] that interfacial defects D3, specific to the Sb 2 Se 3 /CdS interface, were markedly prevalent and severely limiting the voltage and fill factor of the device, and to a lesser extent, the short circuit current. Using a thin interfacial SnO 2 layer after the CdS proved beneficial to both experimental and simulated devices in passivating the pn interface.…”

“…In this work, we propose to use numerical modeling to assess two alternative strategies, each with its own merits, to efficiently passivate the pn interface. SCAPS‐1D [ 13 ] software is used to simulate the performance of Mo/MoSe 2 /Sb 2 (S,Se) 3 /CdS/ZnO/ZnO:Al solar cells in substrate configuration with most of the baseline solar cell parameters used in our model being from in‐lab characterizations, though the defect parameters of D1, D2, and D3 are taken similar to ref [10]. to ensure an accurate comparability between both studies.…”

Role of a Solution-Processed V2O5 Hole Extracting Layer on the Performance of CuO-ZnO-Based Solar Cells

“…Simulation is a widely accepted technique for device modeling, performance analysis, and understanding the overall device physics of the designed heterojunction solar cells. 61 The key advantage of the numerical simulation is that the effect of different physical parameters of the materials on the device performance can be easily investigated. Such a type of investigation provides the guidelines to obtain optimum performance from a designed solar cell without fabricating it in the laboratory.…”