Tandem perovskite/silicon solar cells : Evaluation of silicon surface topography on performances of tandem devices.
The most important R&D challenge of photovoltaic domain is today the elaboration of the next generation of highly efficient solar cells based on perovskite/silicon tandem architecture. In the literature, most of these perovskite/silicon tandem solar cells are elaborated on CMP (chemically and mechanically polished surface) silicon wafers. This configuration is actually not compatible with an industrial development. Very recently CSEM/EPFL demonstrate the elaboration of perovskite/silicon tandem solar cells on standard texturized surface reaching high efficiency up to 31.25 % in combinaison with the use of a specific conformal process for the deposition of the perovskite layer. The goal of the scientific case proposed here is the elaboration of perovskite/silicon heterojunction tandem solar cells with an optimised and industrially compatible surface texturation.
Status: Ongoing
Date of proposal: 22/08/2022
Start date: 17/04/2023
End Date: 21/04/2023
Used Instruments: Scanning Electron Microscopy (SEM). Current density-voltage (J-V) measurement system. External Quantum Efficiency (EQE) setup.
Experimental Technique: Fabrication of tandem perovskite/silicon solar cells. Evaluation of silicon surface topography on tandem device performance. Spin-coating and hybrid thermal evaporation-spin coating processes for perovskite layer deposition.
Experiment Description: The project focused on elaborating tandem solar cells based on Silicon/Perovskite architecture. It investigated the impact of Si topography on Silicon/Perovskite tandem devices performance, comparing flat and textured Si bottom cells. Different processes, including spin-coating and hybrid methods, were used for perovskite deposition on these cells.
Type Samples: Tandem solar cells with Silicon/Perovskite absorbers.
Sample Description: Samples with different Si surface topographies, including chemically polished (CMP) and textured Si bottom cells with varying sizes of pyramids.
Experiment Data Type: Photovoltaic properties (open-circuit voltage, current density, fill factor, and power conversion efficiency). External quantum efficiency data.
Characterization Technics: SEM for structural analysis. J-V measurements for photovoltaic properties. EQE measurements for spectral response.
Characterization Data Type: SEM images showing cross-section and surface of textured Si bottom cells. Photovoltaic parameters of tandem devices. EQE spectra of Si/Perovskite tandem devices.
Analyzed Data: Comparison of tandem solar cells performance based on different Si bottom cell topographies and perovskite deposition methods. Analysis of current mismatch and its impact on the photovoltaic performance.
Main Targets Project: Elaborating efficient Si/Perovskite tandem solar cells with industrially compatible Si surface texturization. Investigating the impact of Si topography on tandem device performance.
Main Achievements Findings: Higher open-circuit voltage observed in solar cells with textured silicon bottom cells and perovskite film deposited by the hybrid method. Best power conversion efficiency of 27.3% achieved using textured Si bottom cell. Current mismatch between the top and bottom cells leading to lower fill factor values in tandem solar cells with textured Si bottom cells. Recognition of the need to optimize the interface and layer properties for enhanced tandem cell performance.