Emission Properties of Poly(3-hexylthiophene) Deposited by Langmuir-Blodgett Method

摘要

We studied emission properties of electroluminescent (EL) devices fabricated by spin-coating and Langmuir-Blodgett [LB] technique. The LB technique has the advantage of precise control of the thickness better than spin-coating method. Poly(3-hexylthiophene) [P3HT] LB films used as the emitting layer in light-emitting devices. LB monolayer was deposited 27 layers onto the indium-tin-oxide [ITO] as Y-type films by the vertical dipping method. In the UV-Vis absorption spectrum, the maximum peak of P3HT-AA LB films and spin-coating films showed about at 500nm and 545nm, respectively. The spectrum of P3HT-AA LB films presented that the synthesized P3HT chain have a more coil-like conformation in the mixed LB films. And current-voltage-light power characteristics and EL spectra of light-emitting devices [LEDs] fabricated by LB method were also studied. In current-voltage-light power characteristics, turn-on voltage of 9V of P3HT LB film devices is higher than 6V of spin-coating devices. And EL spectrum peak appear at 640nm corresponding to 1.9eV. The orange-red light was clearly visible in a dark room.