All-inorganic perovskite quantum dots help realize full-spectrum persistent luminescence tuning

(Nanowerk News) The application of persistence luminescence phosphors in many technological fields have fuelled up a growing demand for rational control over the emission profiles of the phosphors, which, however, remains a daunting challenge so far.
In the study published in Angewwandte Chemie International Edition ("Full-Spectrum Persistent Luminescence Tuning Using All-Inorganic Perovskite Quantum Dots"), the research group led by Prof. CHEN Xueyuan from Fujian Institute of Research on the Structure of Matter (FJIRSM) of Chinese Academy of Sciences reported a novel strategy to fine-tuning the persistent luminescence by using all-inorganic CsPbX3 (X = Cl, Br, and I) perovskite quantum dots (PeQDs) as efficient light conversion materials.
Full-spectrum persistent luminescence tuning using all-inorganic perovskite quantum dots
Full-spectrum persistent luminescence tuning using all-inorganic perovskite quantum dots. (Image by Prof. CHEN’s group) (click on image to enlarge)
In the researchers’ design, CaAl2O4:1%Eu2+, 0.5%Nd3+ (CAO) afterglow phosphor is embedded in a polydimethylsiloxane (PDMS) substrate and spin-coated onto a quartz plate to function as a light storage layer to harvest the ultraviolet light and store the excitation energy, which is subsequently released slowly and yields violet and blue afterglow emission.
The persistently emitted photons from CAO are then absorbed by CsPbX3 PeQDs in the light conversion layer, creating electron–hole pairs (excitons) in the conduction band (CB) and valence band (VB) of PeQDs, followed by photon emission through exciton recombination.
Through bandgap tailoring of CsPbX3 PeQDs by varying the halide compositions, researchers realized tunable persistent luminescence covering the entire visible spectral region, along with highly synchronized afterglow decay inheriting from that of CAO and a color gamut wider than 130% of the NTSC television color standard due to the narrow bandwidth of PeQDs.
Furthermore, based on such efficient afterglow light conversion strategy, they demonstrated the possibility of fabricating a white-emitting persistent light source and dark-light multicolor displays.
These findings provide a general approach for fine-tuning the persistent luminescence of afterglow phosphors, which opens up new opportunities for the application of persistent luminescence materials such as fabricating a white-emitting persistent light source for energy-saving thruway lighting, dark-light multicolor displays in billboard, and afterglow coding for complex data storage or multilevel anticounterfeiting.
Source: Chineses Academy of Sciences
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