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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sistemas poliméricos semicondutores para aplicação como camada ativa em LED. / Polymer semiconductors systems for application as active layer in led.

Oide, Mariane Yuka Tsubaki 07 February 2019 (has links)
Diodos poliméricos emissores de luz (PLEDs) foram produzidos utilizando poli(vinil-carbazol) (PVK), poli(2,7-(9,9-dioctilfluoreno)) (PFO) e poli((1,4-fenileno-2-flúor)-alt-2,7-(9,9-dioctilfluoreno)) (PFPF) dopados com diferentes concentrações de dopante fosforescente tris(2-fenilpiridinato) de irídio(III) [Ir(ppy)3] como camada ativa. Os resultados mostraram que o dispositivo a base de PFO dopado com 4% em massa de Ir(ppy)3 apresentou as maiores eficiências de corrente e de potência luminosa e o espectro eletromagnético do PLED a base de PVK puro apresentou emissão em 540 nm, sugerindo um desbalanceamento de cargas e emissão do óxido de zinco dopado com alumínio (AZO), camada injetora. Assim, estudos da influência da massa molar média do PVK e de sistemas híbridos PVK:AZO nas propriedades elétricas e ópticas dos PLEDs foram elaborados. Resultados mostraram que o AZO possui propriedades foto/eletroluminescentes e é responsável pela emissão larga na região do visível. Os dispositivos híbridos apresentaram emissão próxima ao branco puro, atingindo-se uma pureza de 0,19. / Polymer light emiting diodes (PLEDs) were manufactured using poly(9-vinylcarbazole) (PVK), poly(9,9-dioctylfluorene) (PFO) and poly(9,9-dioctylfluorene-alt-1,4-fluorphenylene) (PFPF) doped with different concentrations of tris-(2-phenylpyridinate) iridium(III) [Ir(ppy)3],a phosphorescent dye, as the active layer. Results showed that PFO based devices doped with 4 wt. % of Ir(ppy)3 presented the highest current and power efficiencies, and the PVK based devices\' electroluminescence spectrum showed an emission centered at 540 nm, suggesting that a charge unbalance and light emission from the injection layer of aluminum doped zinc oxide (AZO) occurred. Therefore, studies based on the PVK:AZO system and different PVK\'s average molar masses were elaborated to observe the PLEDs\' electrical and optical properties. Results showed that AZO is a photo/electroluminescent material and it is responsible for the broad emission in the visible range. The hybrid device showed near pure white light emission and its purity reached 0.19.

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