All–Inorganic Perovskite Quantum Dot–Based Blue Light–Emitting Diodes: Recent Advances and Strategies

Light–emitting diodes (LEDs) based on all–inorganic lead halide perovskite quantum dots (PQDs) have undergone rapid development especially in the past five years, and external quantum efficiencies (EQEs) of the corresponding green– and red–emitting devices have exceeded 23%. However, the blue–emitting devices are facing greater challenges than their counterparts, and their poor luminous efficiency has hindered the display application of PQD–based LEDs (PeQLEDs). This review focuses on the key challenges of blue–emitting PeQLEDs including low EQEs, short operating lifetime, and spectral instability, and discusses the essential mechanism by referring to the latest research. We then systematically summarize the development of preparation methods of blue emission PQDs, as well as the current strategies on alleviating the poor device performance involved in composition engineering, ligand engineering, surface/interface engineering, and device structural engineering. Ultimately, suggestions and outlooks are proposed around the major challenges and future research direction of blue PeQLEDs.