The team fabricated deep-blue LED devices using a solution-processed ultrasmooth thin films of CuI(Hda) as the sole emissive layer (EML). A dual interfacial hydrogen-bonding passivation (DIHP) strategy was used to form H-bonds between the emissive layer and both of its interfaces (Fig. 1) which boosts the device performance by four times. The optimized LEDs achieved a maximum external quantum efficiency of approximately 12.6% which also delivered a maximum brightness of ~4,000 cd m-2 while maintaining a stable deep-blue emission color. The DIHP strategy also enhanced the device stability with the half-brightness operational lifetime (T50) reaching ~204 hours under ambient conditions, significantly surpassing that of untreated devices. These metrics set a new benchmark for deep-blue light emitters based on metal halide materials. In addition, a larger area (4 cm2) LED was fabricated that maintained a high efficiency of ~8% (Fig. 2), demonstrating the scalability of this approach.
Fig. 2: A 2 cm × 2 cm large area CuI(Hda) deep blue LED.
Publication: “Dual interfacial H-bonding enhanced deep-blue hybrid Copper Iodide LEDs”, Nature, 2025, DOI: 10.1038/s41586-025-09257-8
First Author: Kun Zhu
Corresponding Author: Jing Li