Title of article :
Poly(p-phenylenevinylene) by chemical vapor deposition: synthesis, structural evaluation, glass transition, electroluminescence, and photoluminescence
Author/Authors :
Schنfer، نويسنده , , O. and Greiner، نويسنده , , A. and Pommerehne، نويسنده , , J. Mitchell Guss، نويسنده , , W. and Vestweber، نويسنده , , H. and Tak، نويسنده , , H.Y. and Bنssler، نويسنده , , H. and Schmidt، نويسنده , , C. and Lüssem، نويسنده , , G. and Schartel، نويسنده , , B. and Stümpften، نويسنده , , V. and Wendorff، نويسنده , , J.H. and Spiegel، نويسنده , , S. and Mِller، نويسنده , , C. Katharina Spiess، نويسنده , , H.W.، نويسنده ,
Abstract :
Poly(p-phenylenevinylene) (PPV) was prepared via chemical vapor deposition (CVD) by vapor phase pyrolysis of α,α′-dihalogenated p-xylenes or α,α-dihalogenated p-xylenes. Differences in the product composition obtained are discussed. The advantages for the film formation as well as the limitations are reported with respect to the fabrication of light-emitting diode (LED) cells. PPV films were characterized by various techniques. They show a glass transition temperature at 220 °C, a hypsochromic shift of the S1 → S0 transition and higher degree of disorder as compared to ordinary PPV. The current-voltage characteristics of LED cells with PPV prepared via CVD show an unusually high rectification ratio. In contrast to PPV annealed at lower temperatures the formation of an unidentified defect structure was detected by 13C CP-MAS/TOSS spectroscopy with PPV films annealed at higher temperatures.
Keywords :
Synthesis , crystallization , electroluminescence , Poly(p-phenylenevinylene) , Photoluminescence , films , Glass transition
