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All inorganic perovskite quantum dots (QDs) (CsPbX3, X = Cl, Br, I) have been applied on light-emitting devices (LEDs) in recent years due to their excellent optical and optoelectronic properties. However, blue-light emitting perovskite QD LEDs (PQD-LEDs) exhibit poor performances compared with their green- and red-light emitting counterparts. Herein, we fabricated high performing blue-light emitting PQD-LEDs based on phenethylammonium chloride (PEACl) modified CsPb(Cl/Br)3 QDs. Firstly, the PEA-CsPbCl3 QDs were synthesized by introducing certain amounts of PEACl in the conventional hot-injection synthesis process. The merit of our synthesis lies in the fact that not only the Cl vacancies of CsPbCl3 QDs are efficiently modified by introducing the PEACl precursor, but also the partial long-chain organic ligands (OLA) capping on the surface of CsPbCl3 QDs are simultaneously replaced by shorter PEACl chains. Consequently, the PEA-CsPbCl3 QDs emitting at 410 nm with a PLQY of 62.3% were achieved. Furthermore, to meet the requirement of display applications, we exchanged Cl- with Br- ions at room temperature to precisely control the blue emission in the 460-470 nm spectral region and with a maximum PLQY of 80.2% at 470 nm. Finally, the PQD-LEDs based on PEA-CsPb(Cl/Br)3 perovskite QDs emitting at 462, 465, 468 and 470 nm were fabricated. The PQD-LEDs exhibit a maximal EQE of 2.15% and luminance of 620 cd m-2, which provides the highest value of luminance for the PQD-LEDs in the blue spectral range that satisfies the requirement of practical display applications.

All-inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) have received considerable attention in optoelectronic applications owing to their excellent photoluminescence properties. However, low blue-violet fluorescence emission and instability limit their practical application. Herein, we propose to improve the optical properties of CsPbCl3 QDs by co-doping La3+ and F- ions. The co-doped perovskite QDs were successfully synthesized using the hot injection approach, and they exhibited bright blue-violet emission and a high photoluminescence quantum yield of 36.5%, which is one order higher than that of undoped QDs. Enhanced photoluminescence performance compared to the initial CsPbCl3 QDs could be attributed to efficient modification of defects (Cl vacancy) and increased radiative recombination rate by the introduction of the dopants. Moreover, the as-prepared La3+ and F- ions co-doped CsPbCl3 QDs exhibited potential application for anti-counterfeiting.

Colloidal perovskite nanocrystals (NCs), especially the fully inorganic cesium lead halide (CsPbX 3 , X = Cl, Br, I) NCs, have been considered as promising candidates for lighting and display applications due to their narrow band emission, tunable band gap and high photoluminescence quantum yields (QYs). However, owing to the anion exchange in the CsPbX 3 NCs, stable multi-color and white light emissions are difficult to achieve, thus limiting their practical optoelectronic applications. In this work, dual ion Bi 3+ /Mn 2+ codoped CsPbCl 3 perovskite NCs were prepared through the hot injection method for the first time to the best of our knowledge. Through simply adjusting the doping ion concentrations, the codoped NCs exhibited tunable emissions spanning the wide range of correlated color temperature (CCT) from 19 000 K to 4250 K under UV excitation. This interesting spectroscopic behaviour benefits from efficient energy transfer from the perovskite NC host to the intrinsic energy levels of Bi 3+ or Mn 2+ doping ions. Finally, taking advantage of the cooperation between the excitonic transition of the CsPbCl 3 perovskite NC host and the intrinsic emissions from Bi 3+ and Mn 2+ ions, white light emission with the Commission Internationale de l'Eclairage (CIE) color coordinates of (0.33, 0.29) was developed in the codoped CsPbCl 3 NCs.