  We study the blackbody spectrum from slabs of three-dimensional
metallodielectric photonic crystals consisting of gold nanoparticles using an
ab initio multiple-scattering method. The spectra are calculated for different
photonic-crystal slab thicknesses, particle radii and hosting materials. We
find in particular that such crystals exhibit a broadband emission spectrum
above a specific cutoff frequency with emissivity of about 90%. The studied
photonic crystals can be used as efficient selective emitters and can therefore
find application in thermophotovoltaics and sensing.
