Banca de QUALIFICAÇÃO: ADRIANO SANTANA SOARES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: ADRIANO SANTANA SOARES
DATA: 14/03/2013
HORA: 10:00
LOCAL: Auditório da Fisica, CCN
TÍTULO:

Natural product for controlling degradation of MEH-PPV diodes

PALAVRAS-CHAVES:

CNSL; poly[2-methoxy,5-(2-ethylhexoxy)-1,4-phenylene vinylene]; MEH-PPV; dark spots

PÁGINAS: 35
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
SUBÁREA: Física da Matéria Condensada
ESPECIALIDADE: Transp. Eletrônicos e Prop. Elétricas de Superfícies; Interfaces e Películas
RESUMO:

Electronic semiconductor devices with organic active layers are promising substitutes for inorganic based. Applications of OLEDs in large commercial scale find many obstacles, perhaps one the most important is the degradation in short periods of operation. OLEDs based on PPV poly(p-phenylene vinylene), or derivatives of PPV, have two main processes of degradation:  oxidation of the polymer leads to the formation of groups carbonyl substituting the vinylene. Those carbonyl have the effect of quenching the fluorescence and brake the conjugation length of the polymer. The second process involves the formation of localized electrical shorts which do not necessarily cause immediate complete failure of device. In recent years, the Technical Cashew Nut Shell Liquid (CNSL) was analyzed and show that contains alkyl-substituted phenolic compounds; important molecules that show antioxidant activity. This work shows the potential use of technical CNSL as antioxidant for the development of poly[2-methoxy,5-(2-ethylhexoxy)-1,4-phenylene vinylene] (MEH-PPV) OLEDs without taking care with the presence of oxygen. We produce cast films to study photo-degradation using FTIR, in this case, pure films and films with 10% LCC. FTIR clearly show that the appearance of carbonyl groups is retarded in samples containing 10 wt%. However, comparing I vs. V curves with microscopic images it was found that the degradation due to operating the device at high tension primarily occurs in contacts, showing that the degradation due to the appearance of carbonyl is irrelevant in the case of operating the device with voltages around 20V.

MEMBROS DA BANCA:
Presidente - 1534112 - ANGEL ALBERTO HIDALGO
Externo à Instituição - CLEANIO DA LUZ LIMA - CAPES
Externo ao Programa - 1167605 - HELDER NUNES DA CUNHA
Interno - 1714193 - JOSE MILTON ELIAS DE MATOS
Externo ao Programa - 1536094 - MARIA ALEXSANDRA DE SOUSA RIOS