【Frontiers of HaiChuan Technology】Chinese scientists successfully develop a new type of \"night glow\" material

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Chinese scientists have successfully developed a new type of \"night glow\" material. The reason why the precious gemstone \"night glow\" can emit light in the dark is phosphorescence. Due to their ability to emit light in the dark, phosphorescent materials hold great potential for applications in fields such as information encryption and biological imaging. Recently, the research teams led by Jiang Changlong and Yang Liang from the Department of Energy Materials and Device Fabrication at the Institute of Solid State Physics, Hefei Institute of Physical Science, Chinese Academy of Sciences, successfully developed a new method to produce carbon-based polymer nanoparticle materials that exhibit multi-colored, super-long-lasting phosphorescent emission ranging from blue to green. The related research was published in Advanced Science. The phenomenon of phosphorescent materials emitting light in the dark is known as room-temperature phosphorescence. In simple terms, room-temperature phosphorescence is the phenomenon in which a material continues to emit cool light for a period of time after the excitation light source is turned off. The light-emitting mechanism of phosphorescent materials stems from internal \"energy level transitions.\" When phosphorescent materials are excited by external energy (such as from ultraviolet light), their valence electrons that have absorbed energy undergo energy level transitions, and during this process energy is released in the form of photons – this is what we observe as phosphorescence. A team member used a vivid analogy: this process is like a child taking an elevator up to the second floor (stimulated by external energy), and then playfully jumping back down from the second floor to the first floor, one floor at a time (energy level transition). If the first floor is called the ground state and the second floor the excited state, then each step represents an energy level. As the child jumps down, energy is released; this release of energy is what causes the stairs to shake and produce audible knocking sounds. In the case of valence electrons, this corresponds to the release of photons. For phosphorescent materials, valence electrons are like well-behaved children that jump down level by level; therefore this process of jumping takes a long time, which results in the phosphorescence lasting for an extended period. But in the other case, it’s completely different: valence electrons are like unruly children who jump straight from the second floor to the first floor – this shows up as a sudden brief flash of light, followed by darkness again. This short-lived luminescent phenomenon is called fluorescence. To make better use of the phosphorescent phenomenon, scientists need to extend the duration of phosphorescence as much as possible. The new room-temperature phosphorescent materials developed by the research team led by Jiang Changlong and Yang Liang achieved a maximum phosphorescent afterglow duration visible to the naked eye of 49 seconds, a maximum phosphorescent quantum yield of 19.5%, and excellent resistance to photo-bleaching. The new advances in multi-colored, long-lasting room-temperature phosphorescent materials achieved in this research have opened up new directions for scientific investigation, and they also provide innovative solutions for fields such as anti-counterfeiting and information encryption.