The emerging concept of thermophotovoltaic battery is likely to contribute to the development of net zero-carbon built environments. A key element of this battery, generating electrical power in a continuous way, is the photovoltaic cell converting thermal radiation from a body at high temperature, called the emitter, into electricity. But several challenges such as the mitigation of Joule and thermal losses have to be tackled when temperature of the emitter is exceeding 1800 °C. One solution is to use a silicon vertical multijunction cell. Here we experimentally investigate the performances of such a cell for two emitter temperatures (2100 and 2400 °C) and three cell temperatures (25, 50 and 75 °C). The main observation is an expected increase in short-circuit current with increasing emitter temperature, while open-circuit voltage decreases. This specific variation of open-circuit voltage is related to the change in emitter spectrum. When the emitter temperature increases, the sensitivity to cell temperature of the figures of merit is almost similar. These results suggest that a deeper analysis is requested to determine what is the optimum emitter temperature when silicon vertical multijunction cells are used for thermophotovoltaic conversion.