Efficiency Enhancement of Flexible Inorganic Powder Electroluminescent Devices Using the BaTiO3 -MWNT Composite Dielectric Layer

Alternating current inorganic powder electroluminescent (IPEL) devices possess many advantages including wide viewing angle, wide operating temperature range, and easily manufactured by using a screen printing process. This study developed an IPEL devices with low power consumption and high brightness on a transparent polyethylene terephthalate substrate by introducing a composite dielectric layer, which was formed by incorporating single- or multiwall carbon nanotubes (SWNTs or MWNTs) into the BaTiO
₃
-based dielectric layer. The luminous efficiency of the developed devices, called the IPEL: carbon nanotubes (CNT) devices, increased with appropriate incorporation ratios of CNTs, regardless of SWNTs or MWNTs. The optimal device performance was achieved with a 0.5 wt% mixing ratio of MWNTs, in which the power consumption of the device decreased 33.7% and the luminous efficiency increased 50.9% at the brightness of 100 cd/m
²
. The result of bending test with a curvature radius of 1 cm for 10
⁴
times showed that the IPEL:MWNT device had a superior luminous reliability and its variation of the efficiency was less than 6%. The developed IPEL:MWNT device has potential as a candidate in future flexible displays.