Photo- and electro-luminescent properties of 5,10,15,20-tetra-p-tolyl-21H,23H-porphine doped poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] films

In this work we studied both photoluminescence (PL) and electroluminescence (EL) properties of 5, 10, 15, 20-tetra-p-tolyl-21H, 23H-porphine (TTP) doped poly[2-methoxy-5-(2′-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) with the weight percentages of 0, 0.5, 1, 3, 5, 8 and 12, respectively. In the process of PL the significant energy transfer occurs from MEH-PPV to TTP, even though there is a small spectral overlap between the absorption of TTP and the emission of MEH-PPV. For investigation of the process of EL a series of organic light-emitting diodes were fabricated with the device structure of ITO/PEDOT:PSS/TTP-doped polymer layer/Al (ITO = Indium Tin Oxides; PEDOT:PSS = poly (3,4-oxyethyleneoxythiophene): poly-(styrene sulfonate)). In devices in which the TTP was present at 5% the emission of EL was dominated by TTP; at lower doping levels MEH-PPV emission dominated. Moreover, multi-color emission was observed at the doping level below 5%. On the other hand, the mechanism for the EL process was reported.