High-intensity first near-infrared emission through energy migration in multilayered upconversion nanoparticles

Abstract

The development of Tm3+ 807 nm first near-infrared (NIR-I, 700-1000 nm) emission with second near-infrared (NIR-II, 1000-1700 nm) excitation is urgently needed, due to its potential application in biomedicine. In...

Dominant red upconversion emission in LiErF4-based nanoparticles by reducing spontaneous emission of Yb3+

“…When the doping concentration of Yb 3+ increases to 50%, due to the enhancement of EBT from Yb 3+ to Er 3+ , the excitation energy transferred back to Er 3+ in the core is also enhanced, thereby increasing the UC fluorescence intensity. 37 However, with the Yb 3+ concentration further increasing, excessive Yb 3+ ions can lead to excessive energy migration in the first shell, inevitably resulting in energy loss and a decrease in fluorescence. Compared with the Yb 3+ -free sample, the red emission intensity in the sample with 50% Yb 3+ is increased by 3.66 and 1.22 times under 980 and 1532 nm irradiations, respectively.…”

Photoluminescence and energy transfer mechanisms of Tm3+ doped Y2O3 laser crystals: experimental and theoretical insights

“…The performance of lasers operating in 2 μm wavelength regions has expanded interest in recent years due to their functional applications in “eye-safe” surgery systems, mid-infrared solid state lasers, and oscillator power amplifiers. 1–4 The most potential emitter source of 2 μm lasers is probably trivalent rare-earth thulium (Tm 3+ ) doped laser materials. Tm 3+ doped laser crystals can smoothly emit lasers with a wavelength of approximately 2 μm owing to the 3 F 4 → 3 H 6 transition under pumping using an 800 nm diode laser.…”