Design And Preparation Of Amorphous Silicon/Crystalline Silicon Tandem Solar Cell Based On Tunnel Junction

A new type of tandem solar cell structure is proposed.The upper cell is PIN amorphous silicon thin film cell,and the lower cell is epitaxial growth p-n junction crystalline silicon photovoltaic cell.The upper and lower layers are formed by series connection of heavily doped p-n tunnel junction.The upper layer of amorphous silicon cell absorbs the short-wave part of light,provides a higher open circuit voltage,and reduces the high-energy photon loss.The sublayer silicon cell absorbs the remaining long-wave light,combining the advantages of amorphous silicon and crystalline silicon cells.The upper PIN cell was simulated by wxAMPS software,and the lower PN silicon cell was simulated by MATLAB software.The current distribution of the upper and lower cell was obtained respectively.The current density of the upper and lower cell was integrated to obtain the current flow of the upper and lower cell.The theoretical model is analyzed,Several key parameters(short-circuit current,quantum efficiency,open circuit voltage,filling efficiency and conversion efficiency)of tandem cell are analyzed and the relationship between layerI thickness and short-circuit current,quantum efficiency,open circuit voltage,filling efficiency and conversion efficiency is analyzed in detail.The actual cell model is constructed according to the theoretical data,the concrete fabrication of tandem solar cell is completed,these include cleaning of silicon wafers,deposition of amorphous silicon and ITO layers using PECVD instruments,mask pattern design,rotary coating and dryingand photolithography of electrode surfaces.After the manufacture,the large cell was divided into several small pieces and their electrical characteristics were measured separately,the actual data is compared with the theoretical data,the actual deficiencies are analyzed and improvement suggestions are put forward.