The inserted dipole layer enables highly powerful blue perovskite quantum dot-based light-emitting diodes

Persistent efforts have pushed the external quantum efficiencies (EQEs) of blue perovskite light-emitting diodes (LEDs) beyond 25%. However, the power efficiency (PE) of these devices remains limited-a key performance indicator quantifying electricity consumption in LEDs. Here, we incorporate polymer dipoles formed by the ordered dipolar structure of poly(1,1-difluoroethylene) (PVDF) into the CsPbCl_3-xBr_x quantum dot (QD) layer to regulate the injected electrons and holes. Meanwhile, the polar F and H atoms on PVDF molecules can interact with the Pb and Br/Cl ions on QD surface, respectively, thereby suppressing trap-assisted nonradiative losses. These combined features have enabled blue perovskite LED with a higher luminance at a lower driving voltage, resulting in a record PE of 43.9 lm W^-1. Moreover, the device presents a record EQE of 28.7%, a low turn-on voltage of 2.2 V, as well as a maximum luminance of 5474 cd m^-2. These findings provide valuable guidance for developing the energy-conserving perovskite lighting sources.