Description
The high radiative efficiencies and strong absorption coefficients of van der Waals materials position them well for optoelectronic power generation via radiative exchange. These materials have been investigated for use in photovoltaic solar cells, however, their use in infrared thermoradiative and thermophotovoltaic applications remains unexplored. In this study, we fabricate a black phosphorus ($bP$)/molybdenum disulfide ($MoS_2$) van der Waals heterojunction diode and use it in both thermoradiative and thermophotovoltaic operation modes. The diode is formed by stacking exfoliated $bP$ and $MoS_2$ flakes on an $Au$/$Al_2O_3$ back-cavity. Open circuit voltage and short circuit current measurements taken as a function of temperature difference $\Delta T$ between the device and its environment, where $\Delta T = 0$ corresponds to both being at approximately room temperature ($\sim300~\mathrm{K}$), show the device can effectively generate power in both thermophotovoltaic and thermoradiative regimes. A net power density of $\sim80 ~\mathrm{nW}~\mathrm{m}^{-2}$ is achieved at $\Delta T = -50~\mathrm{K}$ (thermoradiative), and $>100 ~\mathrm{\mu W}~\mathrm{m}^{-2}$ at $\Delta T = 100~\mathrm{K}$ (thermophotovoltaic). This represents the first demonstration of thermoradiative power generation using van der Waals materials. Optoelectronic modelling further indicates that the performance is primarily limited by optical out-coupling and internal quantum efficiency. By addressing these losses, the short circuit current density could be increased by up to three orders of magnitude, corresponding to an approximately six orders of magnitude increase in power density.
| I am the presenting author | Yes |
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