Front-electrode design for efficient near-field thermophotovoltaics

The effects of the necessary front electrode in near-field ultrathin resonant thermophotovoltaic cells are analyzed. Absorption inside the transparent conducting electrode limits the power level that can be efficiently converted to electricity and several electrode materials are compared in performance. The assisting grid of metallic fingers suppresses thermal radiation from the emitter in its region across from them, leading to reduced shading losses and wider optimal fingers than usually associated with far-field photovoltaic cells. Promising performances are predicted, reaching 24% at 900K and 48% at 2100K.