Enhanced efficiency can be achieved in the construction of semiconductor optical energy conversion devices such as solar cells by providing a translucent frequency shifting supporting member with appropriate doping such as Al.sub.2 O.sub.3 :Cr.sup.+3 (Ruby) that is capable of shifting the wavelength of incident light energy in the direction of greatest efficiency of the semiconductor device. The efficiency can be further enhanced by providing a crystal perfection accommodation region between the active region of the device and the light frequency shifting substrate.