EL properties of an alternating copolymer composed of phenothiazine and thiophene heterocycles

An alternating copolymer composed of phenothiazine and thiophene heterocycles, poly(PTZV-alt-TV), was synthesized through the Witting polycondensation reaction. The synthesized polymers were characterized using UV-visible, photoluminescence (PL) and electroluminescence (EL) spectroscopy. The poly(PTZV-alt-TV) showed a maximum UV-visible absorption and peak PL emission at 442 nm and 584 nm, respectively. The optical band gap of the polymer was obtained to be 2.74 eV from the absorption onset. The ionization potential of poly(PTZV-alt-TV) was determined to be 5.04 eV. Electroluminescent device was fabricated in an ITO/PEDOT/ poly(PTZV-alt-TV)/Ca/Al configuration. Light emission from this device was observable at voltages greater than 4.0 V. The EL device showed a maximum brightness of 140 cd/m2 and a luminous efficiency of 1.3 × 10−2 cd/A.