Solar-redshift systems comprise an integral array of redshift modules, each having at least a focusing device, a target, and a quantum-dot vessel. The quantum-dot vessel contains quantum dots that emit light having an emission wavelength. The focusing device directs incident solar radiation through a focusing gap and toward the quantum-dot vessel, or into a slab waveguide and then toward the quantum-dot vessel, causing the quantum dots to emit redshifted light having the emission wavelength. The redshifted light is directed to the target, examples of which include a photovoltaic material or a living photosynthetic organism. The target has increased sensitivity or response to photons having the wavelength of the redshifted light. A trapping reflector component of the quantum-dot vessel prevents loss of redshifted light to the environment outside the solar-redshift system and allows undesirable infrared light to be removed from the system.