Multiscale analysis on opto-electrical conversion of thermophotovoltaic cell with doping- and temperature-dependent properties

Abstract

Thermophotovoltaic (TPV) cells offer a novel approach to enhancing sustainable energy applications, both in terms of thermal energy storage extraction and high-temperature heat recovery. Focusing on radiation-to-electric conversion, a coupled carrier dynamics model is employed to analyze the effects of doping- and temperature-dependent properties on the multiscale performance of GaSb TPV systems. First, the effects of changed bandgap, absorption coefficient, and carrier mobility on cell performances are assessed under varying doping levels and temperatures. The effect of carrier mobility counteracts that of the bandgap and absorption coefficient. Ignoring doping dependence results in an overestimation of output power, while disregarding temperature dependence leads to an opposite outcome. Additionally, system performance is evaluated as various parameters change, such as emitter and cell characteristics. Influences of condition-dependent properties are discussed, showing that as emitter temperature increases, both cell and system efficiencies are significantly affected (33.05% and 17.57%, respectively), with a maximum discrepancy of 8%. The impact of these properties can reach up to 29% with changes in emitter emissivity, and the optimized bandwidth of ideal spectral selectivity decreases by 50 nm. When considering condition-dependent properties, system efficiency becomes more sensitive than cell efficiency to emitter characteristics. Furthermore, peaks in efficiency of 39.2% and 40.6% are observed with variations in cell thickness and doping concentration.