Photoresponsive organic electroluminescent devices

We have proposed novel photoresponsive green- and blue-emitting organic electroluminescent (EL) devices combining organic EL diodes with titanyl phthalocyanine as a photoconductive layer. By irradiating red and near-infrared (IR) lights to these devices, green and blue emissions were generated, respectively, well below the turn-on voltage. The results indicate that the devices act as an optical switch and up-converter. The EL response time using a laser pulse was about 300 μs. Above the turn-on voltage, enhancement of the EL intensities was observed with the light irradiation with the ratio of up to 104.