The liquid phase epitaxial growth of pentanary GaInAsSbP lattice matched onto InAs substrates is reported for use in narrow bandgap thermophotovoltaic cells. The epitaxial layers were characterised and exhibited bright photoluminescence up to room temperature. Prototype thermophotovoltaic cells were fabricated, which were sensitive in the mid-infrared spectral range having cut-off wavelengths in the range 4.0-4.5 mu m at room temperature. (C) 2010 Elsevier B.V. All rights reserved.