Understanding and controlling luminescence at the atomic level

Luminescent crystals can be designed to change luminescence intensity or color in response to external stimuli. Organic polymers, hydrogels, and carbon materials comprise the bulk of studies performed on stimuli-responsive luminescence. However, structural disorders present in these materials restrict their responsiveness.

Li et al. reviewed recent developments in the response control of inorganic crystals doped with luminescent ions when subjected to various stimuli. In addition, they presented the underlying mechanism of this behavior, challenges in design, and future directions.

Because of their highly ordered structures, customizable energy transfer pathways, and exceptional responsiveness, doped inorganic crystals have the potential to advance technologies such as anti-counterfeiting and remote sensing. While the development of doped inorganic crystals in this area has been rapid, understanding the fundamental principles that allow for control has resulted in limited progress in the design of responsive materials.

“We correlated diverse stimuli, including light, temperature, humidity, and mechanical forces, with atomic-level changes that dictate emission intensity and color in doped inorganic crystals,” said author Feng Wang. “By unifying these responses within a single framework, we not only elucidate their underlying mechanisms but also propose design principles for next-generation smart materials.”

Future research in this area will focus on using novel stimuli-responsive crystals in more complex environments, including electric and magnetic fields, and developing materials capable of responding to subtle mechanical forces necessary for wearable and flexible electronics.

“This perspective could inspire strategies to enhance material performance and scalability,” said Wang. “Applied research ranging from secure data storage to sensors to optoelectronic devices stand to benefit significantly.”

Source: “Stimuli-responsive luminescence in doped inorganic crystals,” by Shuohan Li, Xin Zhang, Jiangkun Chen, and Feng Wang, Applied Physics Letters (2025). This article can be accessed at https://doi.org/10.1063/5.0240605 .