High Humidity Stability Carbon-Dot-Based Light-Emitting Diode With Thin-Film Encapsulation

Carbon dot (CD) is a new kind of color-converting material for light-emitting diodes (LEDs) because of its good luminesce performance and low toxicity; however, the CD is built by a covalent bond and contains a lot of organic functional group and thus it is a kind of organic material and needs to be protected from oxygen and H
₂
O in the air. Thin-film encapsulation (TFE) is introduced to LED encapsulation, and SiO
₂
nanoparticles are mixed with organic silica resin to replace the traditional LED encapsulation glue. The stability of devices encapsulated with the SiN film and hybrid organic silica resin (H-S resin) are tested at 95% relative humidity (RH) and 25 °C, and the residual photoluminescence (PL) intensity has increased by more than 30% after encapsulation. The stacked encapsulation with both the SiN film and H-S resin can keep residual PL intensity up to 98% after ten days at 95%RH and 25 °C. The temperature rise of the device has almost no change under a low working current and raise 8 °C under a high working current. This encapsulation structure is also available for micro-LED encapsulation.