Thermally stable rare-earth Eu3+-doped CsPbCl3 perovskite quantum dots with controllable blue emission

All inorganic lead halide perovskite CsPbX3 (X = Cl, Br, and I) quantum dots (QDs) have gradually became an outstanding optoelectronic materials. Unfortunately, the presence of the toxic Pb2+ ions and extremely sensitive to oxygen, moisture and heat, greatly limits their practical application in the field of optoelectronic. Here, the Eu3+-doped CsPbCl3 perovskite QDs have been developed to solve these problems without affecting their optical properties. The low-Pb content Cs(Pb1-xEux)Cl3 (x = 0.1-0.5) perovskite QDs with cubic morphologies and high monodispersion are successfully prepared through using the improved hot-injection method. The doping of Eu3+ ions has no effect on the crystal structure, and maintain the tetragonal crystalline structure of CsPbCl3 host. The Eu3+-doped CsPbCl3 perovskite QDs exhibit four typical emissions, including the host emission at-430 nm and the Eu3+ emissions at-590 nm,-616 nm, as well as-695 nm. The relative PL intensity of Eu3+ emission increases with the Eu3+ doping content increasing, attributing to the energy transfer from the host to Eu3+ ions. Meanwhile, the positions of their typical emission bands can be tuned through adjusting the Eu3+ ions doping content, thus, the emission color of perovskite QDs can be controlled within a smaller wavelength range at the blue light area. The lifetimes for the CsPbCl3 host emission rapidly decreases due to the CsPbCl3 host -> Eu3+ energy transfer. The temperature-dependent analysis are investigated, and the characteristics of the stimulated radiation for excitation fluence are observed at low temperatures. The relatively high activation energy indicates that the Cs(Pb1-xEux)Cl3 perovskite QDs have the high thermal stability. The Cs(Pb1-xEux)Cl3 with low toxicity and high thermal stability can further strengthen the competitiveness of perovskite QDs for optoelectronic device applications.