Eu3+-Doped Cspbcl3 Perovskite Quantum Dots with Efficient Controllable Blue Emission and High Thermal Stability

Halide perovskite quantum dots (QDs) are considered to be an outstanding optoelectronic and photonic materials. However, 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. Herein, the Eu3+-doped CsPbCl3 perovskite QDs have been developed to solve these problems without affecting their optical properties. The low-Pb content Cs(Pb x Eu1- x )Cl3 (x = 0.1-0.5) perovskite QDs with cubic morphologies are successfully obtained by 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, but does alter the particle size owing to the difference in ionic radius. Under the UV excitation wavelength of 380 nm, the Cs(Pb1- x Eu x )Cl3 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 though adjusting the Eu3+ ions doping content, thus, the emission color of perovskite QDs can be tuned within a smaller wavelength range at the blue light area. The lifetimes for the CsPbCl3 host emission rapidly decreases owing to the CsPbCl3 host → Eu3+ energy transfer. The temperature-dependent analysis has been investigated, and the signature of the stimulated emission is observed at low temperature for excitation fluence. Meanwhile, the activation energy has been calculated, indicating that the Cs(Pb1- x Eu x )Cl3 QDs possesses good thermal stability. The low-Pb content perovskite QDs with good thermal stability can further strengthen the competitiveness of perovskite QDs for optoelectronic device applications.