Simulation and optimization of a-Si: H/μc-Si: H tandem solar cell with thinner active layers

Abstract

In this study, the performances of a-Si: H(n-i-p) /μc-Si: H(n-i-p) tandem solar cell based on hydrogenated amorphous silicon (a-Si: H) and hydrogenated microcrystalline silicon (μc-Si: H) with thinner active layers were investigated by using numerical simulation. For simulation, a one-dimensional computer code AMPS-1D was used to investigat the effect of the top single cell n+ layer nature, the effect of the top single cell n+ μc-Si: H layer doping concentration (ND) and, the effect of the two active layers thicknesses, i-a-Si: H layer and i-μc-Si: H layer on the performances of the tandem cell. However, the merit figures, like J(V) characteristics at dark and under illumination, the electric fields, the energy band diagrams and, the cell output parameters are calculated and investigated.According to our calculations it is found that, by using a n+μc-Si: H layer with a doping concentration value ND = 1019 cm−3 instead of a n+ a-Si: H layer in the n-i-p top single cell the tandem solar cell performances were performed. It is also obtained, a values of 50 nm and 600 nm for the active layers i-a-Si: H and i-μc-Si: H thicknesses, respectively, are recommended for a-Si: H/μc-Si: H tandem solar cell good performances. Lastly, the tandem solar cell with top single cell n+μc-Si :H layer and with a thinner active layers thicknesses has the higher output parameters (JSC=10.52 mA/cm2, VOC=1414 mV, FF = 80.2 % and, the efficiency = 12.14 %).