Ultraviolet-blue to near-infrared downconversion of Nd3+-Yb3+ 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 Nd3+/Yb3+:beta-YF3 nanocrystals embedded in transparent bulk-glass ceramics. Upon excitation of an Nd3+ ion with a UV-blue photon, Yb3+ ions emit two near-IR photons through an efficient two-step energy transfer from Nd3+ to Yb3+ with Nd3+: F-4(3/2) acting as the intermediate state. (C) 2010 Optical Society of America