Synthesis of highly hygroscopic liquid desiccant for the application of organic light-emitting diodes encapsulation

Abstract

Organic light-emitting diodes (OLEDs) have been widely studied and used due to their excellent photoelectric properties. However, OLEDs suffer from the relatively inferior environmental stability due to their water-susceptible organic compositions. Here, we have developed a novel liquid desiccant (LD) composed of porous CaO particles (0.1819 cm³/g) with high specific surface area (23.37 m2/g). The LD shows a fast water-absorbing rate and a large saturated water-absorbing capacity (0.4995 g/g). The LD is further applied to the OLED encapsulation and tested at 25 °C and relative humidity of 50 %. Compared to the OLED without LD, the LT90 lifetime (time for the brightness decreased to 90 % of the initial brightness) of the OLED with LD is prolonged from 72 h to 240 h under constant current drive. The results revealed that introducing the porous and high specific surface area morphology is an efficient way to improve the hygroscopic property of desiccant. The good performance of LD facilitates the application of OLED in the commercialized application.