Highly pure yellow light emission of perovskite CsPb(BrxI1-x)3 quantum dots and their application for yellow light-emitting diodes

• Published in: Optical materials Vol. 80; pp. 1 - 6
• Main Authors: He, Yuandan, Gong, Jinhui, Zhu, Yiyuan, Feng, Xingcan, Peng, Hong, Wang, Wei, He, Haiyang, Liu, Hu, Wang, Li
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2018
• Subjects: Light emitting diode; Nanocrystal; Perovskite; Quantum dot; Perovskite; Quantum dot; Nanocrystal; Light emitting diode
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2018.04.009

High-quality all-inorganic perovskite CsPb(BrxI1-x)3 quantum dots (QDs) with quantum yield of 50% were systematically studied as yellow light convertor for light emitting diodes (LEDs). A novel heat insulation structure was designed for the QD-converted yellow LEDs. In this structure, a silicone layer was set on top of the GaN LED chip to prevent directly heating of the QDs by the LED chip. Then the CsPb(BrxI1-x)3 QDs were filled in the bowl-shaped silicone layer after ultrasonic dispersion treatment. Finally, an Al2O3 passivation layer was grown on the QDs layer by Atomic Layer Disposition at 40 °C. When x = 0.55, highly pure yellow LEDs with an emission peak at ∼570 nm and a full width at half maximum of 25 nm were achieved. The chromaticity coordinates of the QD-converted yellow LEDs (0.4920 ± 0.0017, 0.4988 ± 0.0053) showed almost no variation under driving current from 5 mA to 150 mA. During an operation period of 60 min, the emission wavelength of the yellow LEDs showed no distinct shift. Moreover, the luminous efficiency of the QD-converted yellow LEDs achieved 13.51 l m/W at 6 mA. These results demonstrated that CsPb(BrxI1-x)3 QDs and the heat insulation structure are promising candidate for high purity yellow LEDs.
•CsPbBrxI3-x quantum dots with quantum yield ∼50% are synthesized.•A heat insulation structure for photo-converted LED using CsPbBrxI3-x quantum dots as the light convertor is proposed.•Pure-yellow LED with narrow emission bandwidth of 25 nm is demonstrated.•Reversible luminous efficiency drop during temperature cycle is observed and discussed.