High brightness and stability pure-blue perovskite light-emitting diodes based on a novel structural quantum-dot film

The further development of perovskite light-emitting diodes (PeLEDs) is severely retarded by poor stability and low brightness of pure-blue emission in the range of 460-470 nm wavelength. Here, we devise a novel structure sandwich panel (SWP) of perovskite quantum dot (QD) film to modulate charge recombination, in which this structure is the first time to be used in LEDs. The SWP film is constructed by inserting a ZnCl2 ultrathin interlayer into the middle of pure-blue emitting (460 nm wavelength) CsPbBr3 QD film. The charge recombination zone is completely limited within the SWP film by the interlayer to alleviate the accumulation of carriers at interfaces of the QD film and hole transport layer, thus reducing the interfacial exciton quenching and Auger recombination. The PeLEDs based on SWP film show stabilized pure-blue emitting at 469 nm and external quantum efficiency (EQE) of 5% that shows low roll-off and maintains over 90% of the initial value at high luminance 10,000 cd m(- 2). The maximum luminance of the device is up to 10,410 cd m(- 2), which is the highest value for pure-blue PeLED reported, meeting the requirement of brightness in pixel for the augmented displays. The operational half-lifetime under continuous operation at the initial luminance of 100 cd m(- 2) is 59 h, which is the best operational stability for the known blue PeLEDs.