Metal halide perovskites (MHPs) has attracted great attention as a promising light emitter for next-generation display application because of their exceptionally high color purity (FWHM ~ 20 nm) and low cost. Although a lot of strategies have been reported, electroluminescence efficiency and stability of MHP still lag behind existing light-emitting diodes (LED). In this talk, we will explore the unique benefits and approaches in utilizing MHPs for display technologies, focusing on innovative nanostructures and material strategy in precisely engineered colloidal perovskite nanocrystals (PNCs) for high luminous efficiency in perovskite light-emitting diodes (PeLEDs). Also, advantages and strategies for commercialization of MHP will be delivered.

First, for high electroluminescence efficiency, we reported a comprehensive material strategy for suppression of defect formation in colloidal perovskite nanocrystal (PNC). Doping of guanidinium (GA+) into formamidinium lead bromide (FAPbBr3) PNCs leads to smaller PNCs with more carrier confinement.[1] Furthermore, a PNCs surface-stabilizing bromine-based small molecule, 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene (TBTB), was applied as a halide vacancy healing agent.[1] In addition, for large-area applications, we developed a modified-bar coating method to fabricate large-area devices which have similar high efficiency to that of small-area devices made by the spin-coating method.[2]

Also, we developed simultaneously efficient, bright, and stable perovskite LEDs by developing an in-situ core/shell PNC structure. By splitting large 3D crystals into nanocrystals and surrounding them with small organic ligands, significant improvement in both efficiency and lifetime could be achieved with both excellent charge transport and charge confinement.[3]

Finally, we developed a hybrid tandem PeLEDs with an ideal optical structure that emits light much efficiently with narrow bandwidth. These developments highlight the potential of MHPs as leading materials for self-emissive displays.[4]

Reference

• [1] Y.-H. Kim, S. Kim, A. Kakekhani, J. Park, J. Park, Y.-H. Lee, H. Xu, S. Nagane, R. B. Wexler, D.-H. Kim, S. H. Jo, L. Martínez-Sarti, P. Tan, A. Sadhanala, G.-S. Park, Y.-W. Kim, B. Hu, H. J. Bolink, S. Yoo, R. H. Friend, A. M. Rappe, T.-W. Lee, Nat. Photonics 2021, 15, 148.
• [2] Y.-H. Kim, J. Park, S. Kim, J. S. Kim, H. Xu, S.-H. Jeong, B. Hu, T.-W. Lee, Nat. Nanotechnol. 2022, 17, 590.
• [3] J. S. Kim, J.-M. Heo, G.-S. Park, S.-J. Woo, C. Cho, H. J. Yun, D.-H. Kim, J. Park, S.-C. Lee, S.-H. Park, E. Yoon, N. C. Greenham, T.-W. Lee, Nature 2022, 611, 688.
• [4] H.-D. Lee, S.-J. Woo, S. Kim, J. Kim, H. Zhou, S. J. Han, K. Y. Jang, D.-H. Kim, J. Park, S. Yoo, T.-W. Lee, Nat. Nanotechnol. 2024, doi: 10.1038/s41565-023-01581-2.