Temperature Coefficients of Quaternary GaₓIn $_{1-x}$ As $_{y}$ Sb $_{1 -y}$ Thermophotovoltaic Cells

We have theoretically reported the cell temperature ( ${T}_{C}$ )-dependent structure and performances for experimentally available n-on-p Ga _x ${\text{In}}_{1 -{x}}$ As _y ${\text{Sb}}_{1 -{y}}$ thermophotovoltaic (TPV) cells with a bandgap at room temperature ( ${E}_{g,\text{RT}}$ ) in the range of 0.50–0.60 eV. It is shown here that ${V}_{\text{OC}}$ and all structure parameters, e.g., active layer thickness and grid separation, of formed cells present a linearly ${T}_{C}$ -relying reduction, while a nonlinear evolution is traced for ${J}_{\text{SC}}$ and efficiency. Importantly, it is further observed that all coefficients desired for the modeling of ${T}_{C}$ -dependent evolution are ${E}_{g,\text{RT}}$ -dependent and can be reasonably yet uniformly modeled by an ${E}_{g,\text{RT}}$ -based cubic function. This provides an effective method to phenomenologically correlate the optimum structure and performances of Ga _x ${\text{In}}_{1 -{x}}$ As _y ${\text{Sb}}_{1 -{y}}$ TPV cell at room temperature with its counterpart beyond room temperature.