Photon management in La2BaZnO5:Tm3+, Yb3+ and La2BaZnO5:Pr3+, Yb3+ by two step cross-relaxation and energy transfer

Broadband ultraviolet to near infrared conversion in Eu2+,Nd3+ co-doped SrAl2O4

In this study, we investigated the quantum cutting (QC) mechanism in Eu²⁺–Nd³-co-doped SrAl₂O₄ microcrystals by fluorescence spectroscopy and decay lifetime analysis. In this material, the near-infrared (NIR) emissions of Nd³⁺ in the range of 800–1200 nm were enhanced under the excitation of the Eu²⁺:4f⁷ → 4f⁶5d¹ transition radiation. The lifetime of the 5d¹ level of Eu²⁺ decreased with the increase in the Nd³⁺ concentration. These results verified the occurrence of cooperative energy transfer (CET) from the Eu²⁺:5d¹ excited state to the Nd³⁺:⁴F_3/2 level, by which one absorbed ultraviolet-visible photon was converted to two NIR photons with an optimal quantum efficiency (QE) of approximately 177.1%. Therefore, this broadband QC material paves the way for a further increase in the conversion efficiency of c-Si solar cells.

In this study, we investigated the quantum cutting (QC) mechanism in Eu²⁺–Nd³-co-doped SrAl₂O₄ microcrystals by fluorescence spectroscopy and decay lifetime analysis.

Broadband near-infrared quantum cutting by Ce–Yb codoped YAG transparent glass ceramics for silicon solar cells

Ce³⁺–Yb³⁺ co-doped transparent glass ceramics containing YAG nanocrystals were prepared by a conventional melt-quenching method. Broadband near infrared quantum cutting was achieved in the glass ceramics and proved to be a cooperative down-conversion process. Under 460 nm excitation, ²F_5/2 to 5d₁ electronic transitions occurred in Ce³⁺ and transferred their energy to two neighboring Yb³⁺. The dependence of the luminescence spectra and decay curves on Yb³⁺ concentration was investigated to understand the energy transfer mechanism. The energy transfer efficiency and the down-conversion quantum efficiency were estimated to be as high as 77.8% and 177.8%, respectively. This work will open a new route towards increased efficiency in silicon solar cells.

Transparent glass ceramics containing YAG nanocrystals were prepared by a conventional melt-quenching method.

Influence of Ho3+ doping on the temperature sensing behavior of Er3+–Yb3+ doped La2CaZnO5 phosphor

Er³⁺/Yb³⁺ and Er³⁺/Ho³⁺/Yb³⁺ codoped La₂CaZnO₅ phosphors were prepared by the combustion synthesis method. The Er³⁺/Yb³⁺-codoped sample exhibited strong green and red UC emissions. The phosphors are suitable for future applications in thermometry.