Cooperative Quantum Cutting in Yb $^{3+}$ –Tb $^{3+}$ Codoped Borosilicate Glasses

Quantum cutting down-conversion (DC) with the emission of two near-infrared photons for each blue photon absorbed is realized in Yb³⁺-Tb³⁺ codoped borosilicate glasses. With the excitation of Tb³⁺ ion by a 484-nm monochromatic light, emission from the ²F_5/2 rarr ²F_7/2 transition of Yb³⁺ ions is observed and this emission is proved to originate from the DC between Tb³⁺ ions and Yb³⁺ ions. Results shows that maximum quantum efficiency reach as high as 153%, which is comparable with that in oxyfluoride glass ceramics in this system. With the advantages of excellent transparence, easy shaping, good stability, and low cost, Yb³⁺-Tb³⁺ codoped borosilicate glasses are potentially used as down-converter layer in silicon-based solar cells.