THE ELECTROLUMINESCENT AND PHOTODIODE DEVICE MADE OF A POLYMER BLEND

Organic thin film diodes made by a polymer blend of methoxy,5-(2'-ethy l-hexoxy)-1,4-phenylenevinylene] (MEH-PPV) and ilyl)-1,4-phenylene)-1, 2-ethenylene-1,4-phenylene] (called the B-polymer) are investigated, T he device of sandwich configuration indium-tin oxide (ITO)/polymer-ble nd/Al emits orange light under forward bias at + 10 V and the same dev ice acts as a photodiode under reverse bias. To investigate the photod iode characteristics, the 516 nm wavelength with 9.5 mW/cm(2) intensit y of light is illuminated through the Al contact side of the device. T he I-V characteristic measurement shows the short circuit current and the open circuit voltage of -1.22 x 10(-9) A/cm(2) and 0.8 V, respecti vely. The ratio of the photocurrent to the dark current is about 4 x 1 0(2) at -2.5 V reverse bias. The maximum d.c. sensitivity is 1.35 x 10 (-5) A/W at -7 V reverse bias voltage with 16 mW/cm(2) intensity of th e incident light, The results indicate the possibility of making photo sensors using this device.