Highly Controllable Synthesis and DFT Calculations of Double/Triple-Halide CsPbX3 (X = Cl, Br, I) Perovskite Quantum Dots: Application to Light-Emitting Diodes

Although all-inorganic CsPbX₃ (X = Cl, Br, I) perovskite quantum dots (PQDs) have evoked exciting new opportunities for optoelectronic applications due to their remarkable optical properties, their emission color tunability has not been investigated to any appreciable extent. In this work, double/triple CsPbX₃ perovskite quantum dots with precise ratios of Cl/Br or Br/I are synthesized and their luminescence (410⁻700 nm) is explored. A group of down-converted CsPbX₃ (X = Cl, Br, I) perovskite quantum dot light-emitting diode (LED) devices were constructed to demonstrate the potential use of such double/triple-halide CsPbX₃ perovskite quantum dots with full-spectrum luminescence. Based on density functional theory, we theoretically explored the properties of CsPbX₃ with double/triple anion atoms. The calculated band gaps provided strong support that the full-spectrum luminescence (410⁻700 nm) of double/triple CsPbX₃ can be realized with the change of the mixed-halide ratios, and hence that such PQDs are of potential use in optoelectronic devices.