  Twisted bilayer two-dimensional electronic systems give rise to many exotic
phenomena and unveil a new frontier for the study of quantum materials. In
photonics, twisted two-dimensional systems coupled via near-field interactions
offer a platform to study localization and lasing. Here, we propose that
twisting can be an unprecedented tool to tune the performance of near-field
thermophotovoltaic systems. Remarkably, through twisting-induced photonic
topological transitions, we achieve significant tuning of the
thermophotovoltaic energy efficiency and power. The underlying mechanism is
related to the change of the photonic iso-frequency contours from elliptical to
hyperbolic geometries in a setup where the hexagonal-boron-nitride metasurface
serves as the heat source and the indium antimonide $p$-$n$ junction serves as
the cell. We find a notably high energy efficiency, nearly 53\% of the Carnot
efficiency, can be achieved in our thermophotovoltaic system, while the output
power can reach to $1.1\times10^4$~W/m$^2$ without requiring a large
temperature difference between the source and the cell. Our results indicate
the promising future of twisted near-field thermophotovoltaics and paves the
way towards tunable, high-performance thermophotovoltaics and infrared
detection.
