Reducing Architecture Limitations for Efficient Blue Perovskite Light‐Emitting Diodes

• Published in: Advanced materials (Weinheim) 2018-05, Vol.30 (20), p.e1706226-n/a
• Main Authors: Gangishetty, Mahesh K., Hou, Shaocong, Quan, Qimin, Congreve, Daniel N.
• Format: Article
• Language: English
• Subjects: blue LEDs; Computer architecture; device architecture; Devices; Diodes; Nanocrystals; Organic light emitting diodes; perovskite LEDs; Transport
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201706226

Light‐emitting diodes utilizing perovskite nanocrystals have generated strong interest in the past several years, with green and red devices showing high efficiencies. Blue devices, however, have lagged significantly behind. Here, it is shown that the device architecture plays a key role in this lag and that NiOx, a transport layer in one of the highest efficiency devices to date, causes a significant reduction in perovskite luminescence lifetime. An alternate transport layer structure which maintains robust nanocrystal emission is proposed. Devices with this architecture show external quantum efficiencies of 0.50% at 469 nm, seven times higher than state‐of‐the‐art devices at that wavelength. Finally, it is demonstrated that this architecture enables efficient devices across the entire blue‐green portion of the spectrum. The improvements demonstrated here open the door to efficient blue perovskite light‐emitting diodes. Blue perovskite light‐emitting diodes have lagged significantly behind red and green ones. It is shown that the device architecture plays a key role. An alternate structure maintains robust perovskite emission, and devices with this architecture show external quantum efficiencies of 0.50% at 469 nm, enabling efficient devices across the entire blue‐green portion of the spectrum.