Examination of the effect of cell thickness on the performance of a tandem nano-gap thermophotovoltaic system

In this paper, a study about the influence of cell thickness on the performance of a tandem thermophotovoltaic (TPV) system is performed in the near-field thermal radiation regime. This system includes an emitter made up of tungsten and two TPV cells made up of Si and GaSb, respectively. The fluctuational electrodynamics accom-panied by the dyadic Green's function are applied in order to calculate the near-field thermal radiation heat flux. The generated photocurrent and the conversion efficiency are computed by solving the charge transport equa-tions. By examination of the effect of TPV cell thicknesses on the performance of both cells, the optimum thicknesses are obtained. Furthermore, it is observed that variation of the n-or p-region thicknesses of the TPV cells also affect the performance of the system. In this regard, the best thickness for n-and p-regions of the first and second cells is also calculated.