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 from photocooling to photoheating. According to the researchers their observations were consistent with their time-resolved measurements, offering insights into the potential and limitations of optical cooling in semiconductor QDs… read more. TECHNICAL ARTICLE
Graphical abstract. Credit: ACS Nano Letters 24, 36, 11255–11261