Rb and Cl co-doped CsPbBr3 QDs for bright blue light emitting diode

Abstract

In this study, Rb ion and Cl ion co-doping were employed to prepare Rb_0.5Cs_0.5PbCl_1.5Br_1.5 QDs, achieving high PLQY with deep blue emission. The doping of A-site cation Rb⁺ induces distortion of [PbX₆]^4- octahedra, leading to a more stable crystal structure, suppressing defect formation, and enhancing resistance to external environments. Simultaneously, Cl⁻ doping at the halogen site allows for tuning of the emission spectrum, resulting in deep blue emission at ∼460 nm. The final blue quantum dots (Rb_0.5Cs_0.5PbCl_1.5Br_1.5 QDs) exhibit a PLQY of 61.90 %, a significant improvement compared to the undoped CsPbCl_1.5Br_1.5 QDs (27.12 %). By encapsulating QDs with hydrophobic polymer PCL, this encapsulation process isolates the QDs from the surrounding environment, significantly enhancing their stability. After placing Rb_0.5Cs_0.5PbCl_1.5Br_1.5/PCL in water for a period of time, the PL intensity remains almost unchanged. These quantum dots were then coated onto a commercial 365 nm GaN LED chip to create a blue LED, with color coordinates of (0.1428, 0.0522). The strategy proposed in this paper holds great promise for various potential applications in blue LEDs and backlight displays.