1 The Mads Clausen Institute, Faculty of Engineering, SDU2 Faculty of Engineering, SDU3 Federal Institute for Materials Research and Testing4 The Mads Clausen Institute, Faculty of Engineering, SDU
Organic materials have been given much attention due to their intriguing properties that can be tailored via synthetic chemistry for specific applications combined with their low price and fairly straight-forward large-scale synthesis. p6P nanofibers can emit polarized light with a highly anisotropic emission profile, can act a sub-wavelength optical waveguides, and could form the basis for a new type of miniature OLEDs. However, p6P molecules suffer reduction of luminescence intensity during photoexcitation under UV light. Such photoreaction is understood as a consequence of the interaction of the nanofibers with oxygen. Operation of devices in vacuum is a solution but the equipment necessary makes impossible the manufacturing of the devices so we propose the use of a coating for reducing bleaching. It is observed that spin-coated PMMA do not damage the morphology of the fragile nanofibers and also do not interfere with the luminescence spectrum from the p6P but it is also not effective in stopping the bleaching. On the other hand, the use of a nonreactant and stable polymer (PMMA) as a direct contact layer on top of the organic nanofibers works as a protecting layer for avoiding modifications of the p6P luminescence spectrum and SiOx as a second layer for blocking the oxygen penetration. Bilayer coating PMMA/SiOx results in a significant reduction of bleaching without affecting significantly the emission spectrum from the nanofibers as well to avoid strong degradation of the nanofibers during electrical measurements.