Thin-film solar cells are second-generation solar cells and they are gaining more traction than the first-generation c-Si solar cells. This is due to the advantages they have over conventional solar cells. The advantages are that they are lightweight, flexible, cheaper and also h
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Thin-film solar cells are second-generation solar cells and they are gaining more traction than the first-generation c-Si solar cells. This is due to the advantages they have over conventional solar cells. The advantages are that they are lightweight, flexible, cheaper and also have better aesthetics than conventional solar cells. Thin-film cells are being processed on a flexible aluminium substrate at HyET Solar which is a Netherlands based company. Their processing technique involves depositing thin-film silicon solar cells on a temporary flexible aluminium substrate. The cells are laminated on a plastic carrier foil and the Al substrate is etched away. HyET solar produces tandem and amorphous single-junction solar cells. For their tandem solar cells, the bottom layer is crystalline. Hence, single-junction crystalline silicon cells are developed at TU Delft to incorporate them into the tandem modules at HyET solar. The crystalline silicon cells deposited at TU Delft are characterized using SEM and raman. The cells deposited at Delft are processed at HyET solar and characterized. Upon characterization, the crystalline fraction and deposition rates increase with an increase in deposition power in the intrinsic layer. The crystalline fraction and deposition rate of a cell does not change by changing the cell thickness of the i-layer. The cell characteristics also change with a change in the silane flow rate in the i-layer. The optimal deposition power with an optimal crystalline fraction was 40W and the corresponding silane flow rate was 3.3 sccm. The deposition rate for a 40W deposition power was 0.41 nm/s. Cells deposited using these parameters were then processed at HyET solar. The cells developed at HyET Solar was shunted. The cause of the shunts was critically analyzed and depositing an amorphous n-layer with a thickness of 80nm seemed to get rid of the shunts. The JV characteristics of the cell were not significant under illumination but the cells displayed diode behaviour when measured in the dark (dark JV). All the deposition parameters except for the deposition time (thickness of deposition) have been optimized for an nc-Si single-junction cell. Further dedicated research on thin-film silicon cells can be performed to improve the electrical characteristics of the cell.