Fig. 6

Numerical analysis of the Si/Gr-based near-field TPV cell. a The schematic of the TPV cell consisting of a pair of Si/Gr heterostructures. The top is emitter with temperature T₁ and the bottom is the PV cell (receiver) with temperature T₂ (=30 °C). The PV cell is biased to have a potential difference V_b. b The interface band diagram of the n-Si/Gr Schottky diode for the PV cell. The physical parameters have been defined in the main text. c The radiated near-field heat flux spectra of emitter (black) and receiver (red) at 700 and 30 °C, respectively. High energy photons in the shaded region with \(\omega > \omega _0 \equiv {{\Phi }}_{\mathrm{b}}{\mathrm{/}}\hbar\) could cross the barrier in the cell and contribute to the photocurrent. d The radiated power density P_rad (dashed line) of the emitter and the portion P_Gr (solid line) solely absorbed by the graphene layer on both i-Si (black) and d-Si (pink) substrates at ΔT ranging from 100 to 700 °C. e Power density P_PV of the i-Si/Gr (black), d-Si/Gr (pink) and InSb (blue) TPV cells together with their net radiation power P_rad (dashed lines). The blackbody radiation power (yellow) is also given for comparison. f The corresponding power efficiency η (=P_PV/P_rad) for the three cells defined in e. The material parameters are specified in the Methods section. The gap is 50 nm. Figure 6 by Yang J et al.