Thin-film electroluminescent devices grown on plastic substrates using an amorphous AlN:Tb3+ phosphor

An alternating current thin-film electroluminescent device has been constructed on a flexible polymer substrate using an amorphous AlN:Tb3+ film as the phosphor. When the device is operated at 170 Vac and at a frequency of 1 kHz, a stripe of green light can be seen emanating from the 0.6 mm×14 mm active area. The electroluminescence spectrum from the device is very similar to the cathodoluminescence and photoluminescence spectra from the amorphous AlN:Tb3+ phosphor. Luminance for this phosphor on plastic substrates is about 1 cd/m2 under optimal conditions. Time-resolved photoluminescence measurements were used to gain insight into the nature of the Tb3+ excited states. The relatively slow (τ=850 μs), single exponential decay of the excited state suggests that quenching via excited state energy migration to trap sites in the semiconductor is negligible.