The rapid advancement of optoelectronic technologies has driven a surge in the development of quantum-dot-based light-emitting devices, especially those using lead halide perovskites such as CsPbBr₃. These materials have shown excellent optical properties, including high photoluminescent efficiency, narrow emission spectra, and tuneable wavelengths. However, inherent toxicity due to lead, along with environmental instability under operational conditions, severely limit their widespread implementation, raising health and ecological concerns.
Moreover, in real environments, these quantum dots are highly sensitive to moisture, oxygen, and temperature: surface ligands can detach easily, while ion migration and hydrolysis processes disrupt the crystal lattice. Meanwhile, defect states promote nonradiative recombination, causing rapid intensity decay, and light exposure or heating may further trigger phase transitions and spectral shifts, accelerating degradation. Efforts to address these issues have led to the exploration of lead-free alternatives such as CsMnBr₃, a manganese-based perovskite known for its non-toxic composition and thermal robustness. Nonetheless, CsMnBr₃ suffers from low luminescence efficiency due to spin- and parity-forbidden d-d transitions of Mn²⁺ ions, restricting its practical utility. Moreover, maintaining long-term stability after integration into devices remains a significant challenge. Embedding these QDs into inorganic glass matrices has emerged as a promising route to enhance stability; however, achieving high luminescence efficiency and operational longevity continues to be an obstacle.
To address these challenges, this work uses lead-free CsMnBr3 quantum dots and introduces Eu3+ to establish an Mn2+→Eu3+ energy-transfer pathway, thereby strengthening radiative emission and reducing defect-related losses to improve luminescence efficiency. In addition, borosilicate glass encapsulation is employed to isolate the quantum dots from water and oxygen, suppressing surface reactions and ion migration and thus markedly enhancing long-term stability. As a result, the strategy not only improves the quantum efficiency but also enables the sample to retain about 97% of its emission intensity after 450 days of storage in water, demonstrating the feasibility of this synergistic approach combining energy-transfer regulation with glass protection.
The Solution: To address these challenges, a team Chinese laboratories successfully synthesized Eu³⁺-doped CsMnBr₃ quantum dots embedded within a borosilicate glass matrix via a melt-quenching process. The incorporation of Eu³⁺ significantly enhanced photoluminescent performance, achieving a quantum yield (PLQY) of 43.45%, more than three times higher than undoped samples. Spectral results and theoretical calculations showed that energy transfer from Mn2+ to Eu3+ played a key role. Rare-earth doping also reduced non-radiative loss. The glass matrix also gave the material high stability. Characterization techniques confirmed the formation of highly crystalline, well-dispersed QDs approximately 1.92 nm in diameter within the glass. The encapsulating glass matrix provided outstanding environmental stability, with the composite retaining optical properties after over 450 days in hot and humid conditions. Prototype devices fabricated with this material, such as LEDs and anti-counterfeiting tags, demonstrated bright, monochromatic red emission and exceptional durability, outperforming comparable commercial products in stability and image clarity.
The Future: Future research on quantum-dot-in-glass materials will focus on extending their lifetime and reducing cost, while enabling multifunctional applications.
This work introduces a scalable melt-quenching route to in situ encapsulate lead-free CsMnBr3:Eu3+ quantum dots within a borosilicate glass host, creating a robust nano-glass composite that simultaneously addresses Pb toxicity and instability. Eu3+ serves as an efficient activator/acceptor, promoting Mn2+→Eu3+ energy migration and boosting the PLQY to 43.45% (3.37× higher than the undoped sample). Glass encapsulation further endows exceptional durability, retaining 97% of the initial PL intensity after 450 days and maintaining bright emission even after water immersion. Finally, the study closes the material-to-device loop by demonstrating UV-responsive anti-counterfeiting graphics/QR codes and prototype red/white LEDs.
The Impact: This work enables scalable, lead-free quantum-dot-in-glass red emitters with high stability, advancing durable anti-counterfeiting optical codes and reliable solid-state lighting components.
The research has been recently published in the online edition of Materials Futures, a prominent international journal in the field of interdisciplinary materials science research.
Reference:Zhijian Ye, Boyu Wang, Yujie Cheng, Denghao Li, Chi Zhang, Zhiyuan Jiang, Gongxun Bai. Highly stable lead-free CsMnBr3:Eu3+ quantum dot-doped photonic glasses for lighting and display applications[J]. Materials Futures, 2026, 5(3): 035301. DOI: 10.1088/2752-5724/ae4b59
