The liquid phase epitaxial growth of InAs0.91Sb0.09 lattice-matched onto GaSb is reported for use in the active region of a mid-infrared light-emitting diode. Epitaxy was carried out from Sb-rich solution using Gd gettering to purify the material. The photoluminescence and electroluminescence emission spectra were studied over the temperature range 4–300 K using different excitation intensities. Interpretation of the resulting spectra revealed the existence of two acceptor levels with activation energies of 8 meV and 16 meV. Room temperature electroluminescence at 4.2 µm was readily obtained from homo-junction p–i–n diodes fabricated from this material. The temperature dependence of the electroluminescence was studied and the decrease in the radiative recombination coefficient was found to be primarily responsible for the luminescence quenching.