Sínteses e estudo fotofísico de materiais fluorescentes semicondutores baseados em silsesquioxanos
Data
2020-10-08
Autores
Gloria, Diego Coelho Sanches 
Orientadores
Domingues, Raquel A.
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A tecnologia de dispositivos orgânicos emissores é parte integrante da sociedade moderna com aplicações desde telas de celulares e televisores (OLEDs) a placas solares (OPVs) e transistores (DE ABREU ALVES et al., 2010). A melhoria das propriedades desses dispositivos, portanto, é de grande interesse, e um caminho promissor para esse fim é a obtenção de materiais híbridos com melhores propriedades e menores desvantagens que seus precursores puros (CALLISTER; WILEY, 2014). Os materiais da classe dos benzenos e tiofenos já são amplamente utilizados em dispositivos orgânicos emissores de luz (OLEDs) e por esse motivo foram escolhidos.
Neste trabalho, foram obtidos materiais fluorescentes híbridos (denominados L6) à base de silsesquioxanos poliédricos octavinilsubstituídos (T8), pela substituição, em dimetilformamida, dos grupos terminais vinil por moléculas de bromobenzeno e 3-bromotiofeno. Também foram obtidos filmes finos de L6 em matriz de polivinilcarbazol (PVK) por solubilização em THF e deposição em substrato de vidro recoberto com oxido de índio e estanho (ITO) por processo de spin coating. A estrutura obtida foi submetida à espectroscopia no infravermelho com transformada de Fourier (FTIR) e apresentou indícios fortes da formação do material visado. As análises fotofísicas de espectroscopia de absorção ultravioleta-visível (Uv-Vis) e espectroscopia de fluorescência no estado estacionário foram obtidas para a amostra bem como seus precursores para efeito de comparação. O L6 apresentou espectro de emissão de grande abrangência na região do ultravioleta próximo - visível (em especial na região do azul), sendo promissor para futuros trabalhos de modulação e aplicação em dispositivos emissores.
Organic emissive devices are present in a variety of applications in modern society, ranging from cellphone and television screens (OLEDs) to solar panels (OPVs) and transistors (DE ABREU ALVES et al., 2010). The improvement of the aforementioned materials is therefore of great interest and hybrid materials show great promise by presenting better properties with lesser disadvantages than their precursor counterparts. Materials based of benzenes and thiophenes are already known to be effective in organic devices applications and therefore were chosen for this work. In this work, fluorescent materials (denominated L6) based on polyhedral octavinyl substituted silsesquioxanes were obtained by substituting vinyl terminal groups for bromobenzene and 3-bromotiophene. Blends of L6 and polivinyl carbazole (PVK) thin films were also obtained by solubilization in THF and depositing in ITO substrate via spin coating. The structure obtained was characterized via Fourier-transform infrared spectroscopy (FTIR) showing strong indications the material was formed successfully. Photophysical properties were obtained for L6, and its precursors by ultraviolet-visible absorption spectroscopy (Uv-Vis) and steady state fluorescence spectroscopy. Photophysical properties of L6 have shown a broad emission spectrum ranging from near-ultraviolet to visible (especially in the blue region) showing great promise in emission modulation and emissive devices.
Organic emissive devices are present in a variety of applications in modern society, ranging from cellphone and television screens (OLEDs) to solar panels (OPVs) and transistors (DE ABREU ALVES et al., 2010). The improvement of the aforementioned materials is therefore of great interest and hybrid materials show great promise by presenting better properties with lesser disadvantages than their precursor counterparts. Materials based of benzenes and thiophenes are already known to be effective in organic devices applications and therefore were chosen for this work. In this work, fluorescent materials (denominated L6) based on polyhedral octavinyl substituted silsesquioxanes were obtained by substituting vinyl terminal groups for bromobenzene and 3-bromotiophene. Blends of L6 and polivinyl carbazole (PVK) thin films were also obtained by solubilization in THF and depositing in ITO substrate via spin coating. The structure obtained was characterized via Fourier-transform infrared spectroscopy (FTIR) showing strong indications the material was formed successfully. Photophysical properties were obtained for L6, and its precursors by ultraviolet-visible absorption spectroscopy (Uv-Vis) and steady state fluorescence spectroscopy. Photophysical properties of L6 have shown a broad emission spectrum ranging from near-ultraviolet to visible (especially in the blue region) showing great promise in emission modulation and emissive devices.