Ultraviolet-blue to near-infrared downconversion of Nd^3+-Yb^3+ couple

To reduce energy losses by thermalization of charge carriers in a silicon solar cell, quantum-cutting luminescent materials are desired for the efficient downconversion of UV-visible radiation into near-IR radiation. In this Letter, quantum cutting involving emission of two near-IR photons for each UV-blue photon absorbed is demonstrated in Nd(3+)/Yb(3+):beta-YF(3) nanocrystals embedded in transparent bulk-glass ceramics. Upon excitation of an Nd(3+) ion with a UV-blue photon, Yb(3+) ions emit two near-IR photons through an efficient two-step energy transfer from Nd(3+) to Yb(3+) with Nd(3+):(4)F(3/2) acting as the intermediate state.