Enhancement in the multi-junction thermophotovoltaic system based on near-field heat transfer and hyperbolic metamaterial

•A multijunction thermophotovoltaic coupled with near-field radiation is proposed.•Hyperbolic metamaterial and surface coating are used to improve near-field radiation.•The new thermophotovoltaic system can achieve a conversion efficiency of 45.26%. A multi-junction thermophotovoltaic system based on near-field radiation and hyperbolic metamaterial was developed. The multilayer near-field system is studied through the fluctuational electrodynamics based on dyadic Green's function and a recursive calculation model, whereas the external quantum efficiency, open-circuit voltage and fill factor are considered to evaluate the performance of the photovoltaic cell. The system expands the available spectrum to 1720–3650 nm so that more photons can be recovered. The near-field radiative transfer is further improved owing to the infinite wavevector in the hyperbolic metamaterial. The results demonstrate that the multi-junction system generates 4.7236 × 106 W/m2 of electricity with a conversion efficiency of 45.26%, achieving 1.3 times (2.38 times) more electricity with 15.3% (25.95%) higher conversion efficiency than the single InGaAsSb (InAs) cell. The study further improves the performance of the multi-junction thermophotovoltaic and paves the way to design a more efficient near-field multi-junction thermophotovoltaic system.