Quantum-dot array with a random rough interface encapsulated by atomic layer deposition.

This Letter proposes the use of atomic layer deposition (ALD) encapsulation as a stability-improving approach for a quantum-dot micro-structural array (QDMA) with a random rough interface. The QDMA is first prepared by screen printing technology on an edge-lit light-guide plate (LGP) for backlight application. A flexible aluminum oxide film is then densely deposited onto the rough surface of the QDMA. The influences of two key factors, the reaction temperature and deposition thickness, on the encapsulation effect and output performance of this QD backlight are discussed. After ALD encapsulation, the water vapor transmission rate was measured to be less than 0.014 g/(m2 day). The average luminance of the encapsulated QD backlight remained stable after continuous working for 200 h, while an unencapsulated QD backlight lost over 50% of its initial luminance. The complete attenuation trend for the encapsulated QD backlight was analyzed in a more demanding testing environment, and results showed that 80% (>3000 cd/m2) of the initial luminance was maintained after 250 h at a high temperature of 70 °C and a relative humidity of 90%. The mechanism behind these experimental results is also discussed.