Phys.org November 26, 2024 Highly efficient anti-Stokes (AS) photoluminescence (PL) is observed from halide perovskite quantum dots (QDs) due to their strong electron–phonon interactions. However, the PL quantum efficiency in QDs is primarily dominated by multiparticle nonradiative Auger recombination processes under intense photoexcitation, which impose limits on the optical cooling gain. Researchers in Japan investigated the Auger recombination of dot-in-crystal perovskites and quantitatively estimated the maximum optical cooling gain and the corresponding excitation intensity. Their optical cooling experiments demonstrated a maximum photo cooling of approximately 9 K from room temperature confirming that increasing the excitation intensity led to a transition […]
Tag Archives: Photoluminescence
Chromium replaces rare and expensive noble metals
Science Daily August 14, 2023 Researchers in Switzerland developed chromium compounds, very similar to those used in the past, that can replace the noble metals osmium and ruthenium. When irradiated with a red lamp the new chromium compounds the energy from the light could be stored in molecules which could serve as power source. They demonstrated it by building the chromium compounds into a stiff organic molecular framework consisting of carbon, nitrogen, and hydrogen. The stiff framework ensured that the chromium atoms were well packaged. The tailor-made environment minimized energy losses due to undesired molecular vibrations and to optimize the […]
Nanoantennas directing a bright future
Nanowerk December 21, 2022 Phosphor plates combined with nanoantenna, enable spatial and spectral control over luminescence. While the emission enhancement in a specific direction has been reported in nanoantenna studies, the evaluation of the total distribution of radiation as well as the conversion efficiency is largely missing. An international team of researchers (Japan, China) developed nanoantenna phosphors consist of a hexagonal array of titanium dioxide (TiO2) nanoparticles, fabricated on a phosphor plate of yttrium aluminum garnet doped with Ce3+ (YAG:Ce). They visualized the distribution of photoluminescence from the nanoantenna phosphor into forward, backward, and side directions by using an integrating […]