A domestic research team led by Professor Tae-Woo Lee (Department of Materials Science and Engineering, Seoul National University, Republic of Korea & SN Display Co., Ltd) has developed a hierarchical-shell perovskite nanocrystal technology that simultaneously overcomes the long-standing instability of metal-halide perovskite emitters while achieving record-breaking quantum yield, operational stability, and scalability. This breakthrough paves the way for next-generation vivid-color display technologies. The results were published in the world's leading academic journal Science on January 15 as a cover article.
With more than 70% of human information perception relying on vision, display technology has long been regarded as one of the most important core industries in modern society. In the 1990s, Japan dominated the global display market, but Korea rose to leadership through aggressive investment in LCD and OLED technologies. In recent years, however, Chinese display manufacturers have rapidly expanded their market share with strong governmental support, while the technological gap in OLED has steadily narrowed. Under these circumstances, the development of a fundamentally new display technology that can surpass existing OLED systems has become an urgent national and industrial challenge.
From this perspective, perovskite emitters, an area in which Professor Lee's research group has played a leading role since 2014, have emerged as highly promising candidates for next-generation displays. Perovskites possess an ionic crystal structure composed of organic or inorganic cations, center metal cation, and halide anions, endowing them with exceptionally high color purity, excellent optoelectronic properties, low material cost, and facile wavelength tunability. These advantages have positioned perovskite emitters as strong contenders for ultrahigh-definition televisions as well as emerging augmented- and virtual-reality displays.
Realizing such next-generation displays requires compliance with the Rec. 2020 color standard, which expands the achievable color gamut by approximately 40% compared with the widely used DCI-P3 standard, enabling more vivid and faithful reproduction of natural colors. However, this stringent requirement cannot be met by conventional organic emitters or quantum dots, whose emission spectra remain relatively broad, with full widths at half maximum of approximately 50 nm and 30 nm, respectively. In contrast, perovskite emitters exhibit intrinsically narrow emission linewidths of around 20 nm, making them uniquely capable of satisfying the Rec. 2020 standard.
Over the past decade, Professor Lee's research group has led the global perovskite light-emitting diode (PeLED) field by continuously breaking efficiency and stability records. Since initiative publication regarding on the bright and multi-color PeLEDs with external quantum efficiency (EQE) of ~0.1% in 2014, the group in 2015 increased the external quantum efficiency of PeLEDs from 0.1% to 8.53% within a single year, reporting the milestone in Science, which has been recognized as the first efficient PeLED in the field and cited more than 3100 times. Subsequent studies introduced highly emissive perovskite nanocrystals and further raised device efficiencies beyond 20% (Nature Photonics 2021, Nature Nanotechnology 2022). In 2022, the group achieved a near-theoretical external quantum efficiency of 28.9% together with an operational lifetime of approximately 30,000 hours in perovskite LEDs, reported in Nature. These achievements demonstrated that electrically driven perovskite LEDs could approach commercial performance.
In the present Science study, the group advances beyond device-level demonstrations and addresses the remaining critical bottleneck: solid-state perovskite emitters for down-conversion display applications. In practical display and lighting systems, particularly blue-pumped color-conversion platforms, solid emitters must simultaneously exhibit strong absorption and high photoluminescence quantum yield (PLQY), because the overall light-conversion efficiency is governed by the external quantum yield (EQY = absorptance × PLQY). However, for nearly all known solid emitters, increasing concentration to enhance absorption inevitably induces concentration quenching and self-absorption–related nonradiative losses, limiting EQY to below approximately 65%.
Colloidal perovskite nanocrystals (PeNCs) are widely regarded as ideal candidates for high-EQY solid emitters due to their exceptional color purity and strong absorption coefficients, and they can exhibit PLQY values exceeding 95% in well-passivated solutions. Nevertheless, their soft ionic lattices and chemically labile surfaces render them highly vulnerable to operational stressors such as light, heat, moisture, and oxygen, leading to rapid PLQY decay and short operational lifetimes in solid films.
To fundamentally overcome these limitations, Professor Lee's group developed a new stabilization strategy based on a hierarchical shell architecture composed of inter-bonded PbSO₄, SiO₂, and polymer layers . Unlike conventional approaches that rely on weakly bound surface ligands or passive encapsulation, the hierarchical shell chemically interlocks both the perovskite lattice and the surface, effectively suppressing lattice softening, ion migration, and interfacial chemical reactions that accelerate degradation under operational conditions.
As a result, perovskite nanocrystal films achieved a photoluminescence quantum yield (PLQY) of 100% while maintaining unprecedented stability under conditions relevant to real-world operation. The stabilized films exhibited a T90 lifetime of 3,900 hours under accelerated humid-thermal aging at 60 °C and 90% relative humidity, as well as an extrapolated T90 lifetime of 27,234 hours under continuous blue-light irradiation. These values far exceed previously reported results for perovskite nanocrystals and surpass widely accepted commercial aging benchmarks. Importantly, the near-unity PLQY enables efficient photon recycling, allowing the external quantum yield of solid films to reach 91.4%, the highest value reported among all known solid-state emitters, including phosphors, organic emitters, quantum dots, carbon dots, metal nanoclusters, and other halide perovskites.
Beyond optical performance, the hierarchical shell structure also provides excellent processability and environmental safety. The shell effectively blocks Pb²⁺ release into water, ensuring intrinsic environmental safety, while cytotoxicity tests confirmed healthy cell proliferation comparable to standard polystyrene culture substrates. Furthermore, the stabilized perovskite nanocrystals are fully compatible with inkjet printing and high-resolution photolithographic patterning, enabling pixel densities exceeding 3,500 pixels per inch, which are required for next-generation micro-LED and augmented- and virtual-reality displays.
The strategy also demonstrates outstanding scalability and manufacturing compatibility. Through collaboration with SN Display Co., Ltd., a venture company co-founded by Professor Lee with support from Seoul National University, the team successfully fabricated uniform perovskite nanocrystal color-conversion films over large areas using 0.6 m × 3.2 m roll-to-roll printing. By leveraging this compatibility with standard display manufacturing processes, prototype 10.1-inch tablets, 28-inch and 32-inch monitors, and 43-inch and 75-inch televisions were demonstrated, all exhibiting uniform brightness and vivid color reproduction. These displays achieved color-gamut area ratios exceeding 97% (area ratio) of Rec. 2020, outperforming commercial LCDs, InP quantum dots, and OLED-based devices.
Professor Tae-Woo Lee said, "By developing a hierarchical shell that locks both the soft lattice and the labile surface of perovskite nanocrystals, we have achieved near-unity efficiency and commercial-grade operational lifetime simultaneously. This breakthrough demonstrates that perovskite emitters can move beyond laboratory research and serve as a core industrial technology for future high-color-purity displays."
This work was carried out jointly with primarily SN Display Co., Ltd., Imperial College London, University of Cambridge, Hanyang University, KAIST, University of Tennessee, Universidad de Valencia, and PEROLED Co., Ltd., with Seoul National University playing the leading role.
The first author, Dr. Qingsen Zeng, is an Assistant Research Professor in the Department of Materials Science and Engineering at Seoul National University, working with Prof. Tae-Woo Lee. His research focuses on halide perovskite nanocrystals for light-emitting applications, including color-conversion displays, single-photon emitters, and superlattice LEDs.
□ Curriculum Vitae (Prof. Tae-Woo Lee)
1. Personal Information
○ Professor of Department of Materials Science and Engineering, Seoul National University
