TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: In the device (D1): the composition of the second region is operable to absorb a portion of the incident radiation and transfer a portion of the absorbed incident radiation to the first region; the second region is of a composition comprising (I); the second region comprises a first layer and a second layer where the first layer is a first composition comprising (I) and the second layer is a second composition comprising carbon-silicon-germanium-tin of formula (CaSibGecSnd) (II); the composition of the first region of formula ((RE1)p(RE2)q (RE3)r(J1)s(J2)t); and the second region is operable to convert a portion of the incident radiation from a first energy to a second energy. In the device (D2), the first region is operable to photoluminesce at a predetermined wavelength as determined by the first composition. In the device (D3): the first region has a composition comprising gadolinium-erbium oxide of formula ((Gd1-xErx)2O3) with erbium present at 5-20 atom%; the second region has a composition comprising (I); the second region has a composition comprising germanium-silicon-tin of formula (Ge1-x-ySixSny), where the band gap is 0.70-1.50 eV; the second region is many quantum dots or nano-crystals distributed in a predetermined fashion within the first region; and the second region is a layer of group IV semiconductor material (preferably samarium) in contact with the first region. In the device (D3) the first region comprises a first portion of first composition, (rare earth oxide)1, and first thickness adjacent the photovoltaic cell and a second portion of second composition, (rare earth oxide)2, and second thickness, separated from the first portion by the second region where the first portion and the second portion exert a strain on the second region so that the second region is operable to convert a portion of the incident radiation from a first energy to a second energy.(RE) = rare earth;(J1), (J2) = O, N or P;p, q, t = 0-5;r = greater than 0; ands = less than or equal to 5.