Silicon-coated CdZnSeS/ZnS quantum dots contribute to great performance white light-emitting diodes

The combination of red quantum dots with YAG phosphors was used to improve color rendering of LEDs and color gamut of LED backlight. To further improve the stability of quantum dots applications, we encapsulate quantum dots with silicon dioxide. Quantum dots have a certain stability enhancement after coating silica. And the quantum dots-based LEDs fabricated using the modified quantum dots have luminous efficiency of up to 114 lm/w under 30 mA. At the same time, we investigated the temperature tolerance, UV stability and thermal characteristics of quantum dots devices. At the high temperature of 150 ℃, the photoluminescence intensity of the silicon-coated quantum dots increases rather than decreases. In contrast, untreated quantum dots are almost ineffective. Under different operating currents and ambient temperatures, the correlation color temperature, luminous flux, color rendering index and coordinates stability of the silica encapsulated quantum dots device is better than the untreated one. After one month of accelerated aging test, the quantum dots devices have nearly stable optical parameters, such as luminous flux and color rendering index, and high reliability. A set of characteristics indicate that silica-coated quantum dots devices are well suited for large-scale industrial production and commercial applications. •The light efficiency of the silica coated QDs LED improved while the QDs was applied to photoluminescence.•The electroluminescence spectra of the modified QDs LEDs is stable under 30 mA–300 mA.•The aging experiment of quantum dots shows a good reliability of modified QDs LED devices.