Bifacial near-field thermophotovoltaic converter with internal cooling channels in silicon support layers

Bifacial near-field thermophotovoltaic (NF-TPV) converters enhance power output over monofacial designs by absorbing radiative heat flux from both sides of the photovoltaic (PV) cell. However, prior bifacial converters have overlooked key performance-limiting factors in electrode design, including shading and series resistance losses. In addition, conventional side cooling restricts effective heat dissipation, raising PV cell temperature, and reducing performance under high photocurrent. To address these challenges, we propose a bifacial NF-TPV converter featuring internal cooling channels embedded in silicon support layers, aligned with multi-busbar electrode to minimize shading and series resistance losses while enhancing cooling performance. A fully coupled radiative–electrical–thermal model is developed by integrating fluctuational electrodynamics, minority carrier separation model, and computational fluid dynamics, enabling accurate prediction of PV cell temperature distribution and impact on performance. Comparative analysis with monofacial and side-cooled bifacial NF-TPV converters shows that the proposed internal cooling design consistently achieves higher power output across emitter temperatures of (1100 ∼ 1900 K) and PV cell widths of (1 ∼ 7 mm). Notably, the required cooling power remains below 1.0% of output power at 1500 K. These results demonstrate that internal cooling, combined with optimized electrodes, enhances efficiency and scalability for high-temperature thermal energy harvesting.