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Kinetic mechanism of luminescence of manganese-doped non-lead double perovskite nanocrystals of Dalian Institute of Chemical Technology
[ Instrument Network Instrument R & D ] Recently, Han Keli, a researcher in the research team of reaction kinetics of complex molecular systems of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, revealed the kinetic mechanism of manganese-doped non-lead biperovskite nanocrystals. The team successfully synthesized undoped and manganese ion-doped non-lead biperovskite nanocrystals, and discussed its size effect and luminescent kinetic mechanism in detail. Undoped nanocrystals emit blue fluorescence. By doping manganese ions, bright orange-red fluorescence emission is achieved.
Manganese, the chemical symbol is Mn, and its atomic number is 25. It is an off-white, hard, brittle, and shiny transition metal. Pure metal manganese is a slightly softer metal than iron. Manganese with a small amount of impurities is firm, brittle, and wet. It will oxidize everywhere. Manganese is widely present in nature. The soil contains 0.25% of manganese, and tea, wheat and hard-shell fruits contain more manganese. Manganese-exposed operations include crushed stone, mining, welding, production of dry batteries, and dye industry. In 1774, Gann separated manganese metal. Bergman named it manganese. Manganese can be prepared by reducing the manganese ore with an aluminothermic method. The entry introduces the history of manganese discovery, development status at home and abroad, physical and chemical properties, preparation methods, application fields, distribution, and safety measures.
Non-lead double perovskite nanocrystals are expected to solve the toxicity and instability of lead-based perovskite nanocrystals. In recent years, researchers have focused on their wide-band white light emission, and relatively few studies have focused on the fluorescence emission of other specific colors. The doping strategy can effectively improve the optical properties and stability of the halogen perovskite nanocrystals. As far as manganese ion-doped systems are concerned, although dopant emission is an area of ​​interest to researchers, it is often accompanied by band-edge emission or self-trapping emission that competes with it. Moreover, the size effect and kinetic mechanism of manganese-doped non-lead double perovskite nanocrystals need further research.
The technical principle of nanocrystals is TAC (Template Assisted Crystallization) technology, that is, ionic crystallization technology. Just like the energy generated during the volcanic eruption will form crystals and diamonds, the energy generated by the atomic nucleus on the nanocrystal high-energy polymerization spheres It can transform calcium, magnesium and bicarbonate ions in water into crystals. They are insoluble in water and do not sink to the bottom of the water. Scale has been dissolved and discharged on the inner wall and in the boiling water furnace, which improves the water flux and thermal efficiency;
In this work, the team successfully synthesized undoped and manganese-doped direct band gap sodium-based non-lead biperovskite nanocrystals. Nanocrystals not doped with manganese ions have blue fluorescence. After doping manganese ions, it showed a single, pure manganese dopant to emit light, and the fluorescence quantum yield reached 44.6%. Researchers have combined steady-state and transient spectroscopy techniques to prove that their bright, pure manganese dopant fluorescence is mainly due to the dark self-trapping auxiliary process. In addition, the team has further studied the size effect of dopant emitting systems. This work emphasizes that the rational use of semi-energy bands of semiconductor nanomaterials has important guiding significance for the design of high-performance semiconductor nanomaterials.
Source: Encyclopedia, Dalian Institute of Chemical Physics