GaSb thermophotovoltaic (TPV) cells are the most suitable choice for modern TPV generators, both in terms of efficiency and simplicity of the diffusion technology used. Actually, TPV generators based on GaSb solar cells are the only ones available on the market. However, TPV cells with band gaps (Eg) lower than GaSb are expected to be advantageous for low‐temperature (< 1000°C) non‐wavelength‐selective TPV radiators because they provide more effective absorption of the blackbody infrared radiation. In this work, together with GaSb (Eg= 0.72 eV), semiconductors with a lower Eg‐ Ge (Eg= 0.66 eV), InGaSb (Eg= 0.60 eV), InGaAsSb (Eg= 0.55 eV) and InAsSbP (Eg= 0.39 eV) ‐ were studied for TPV cells. InGaAsSb cells seem to be the most promising candidate to replace GaSb cells in the low‐temperature TPV generators. © 2003 American Institute of Physics