A solar power plant (10) capable of generating electricity comprising a light pipe carrying highly concentrated solar light (19), a hot reservoir (24), a cold reservoir (20), and a plurality of large-scale solid-state nano-structured photonic crystals (12) that are capable of recycling out-of-band photons with transition energies associated with a photovoltaic cell (13) into photons with in-band energies associated with the same photovoltaic cell (13) when photon energy is subjected to propagation through a thermal temperature gradient that is held across a suitably nano-structured photonic crystal (12). The input thermal photons from the hot thermal reservoir (24) are shifted in energy to the optimal photovoltaic cell energy for electron-hole pair generation by work that is expanded by the heat engine to convert said input photons into phonons and then back to photons again at a new wavelength through a process of phonon rethermalization occurring inside the nano-structured photonic crystal (12).