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Effect of DIO on the emission of light-emitting diodes based on polymer blends

Morgado, J. ; Pereira, J. ; Farinhas, J.

Effect of DIO on the emission of light-emitting diodes based on polymer blends, Proc International Conf. on Materials for Advanced Technologies - ICMAT, Singapore, Singapore, Vol. nd, pp. nd - nd, June, 2017.

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The emission colour of polymer light-emitting diodes can be tuned by modification of the chemical structure of the polymer or upon blending. Blends combining polymers with adequate frontier energy levels alignment and spectral overlap, by controlling the efficiency of the energy transfer, have been widely explored. The efficiency of the energy cascade, from the polymer with wider energy gap to that with lower energy gap, will depend also on the distance between them. This means that the control of the phase separation in the blends can be used to turn on or off that process.
In this communication we report on the use of 1,8-diodooctane (DIO) to control the phase separation in polymer blends and, therefore, the final emission colour of LEDs based on such blends. We have studied binary [1] and ternary blends where a partial switching off of the energy transfer processes is achieved upon addition of DIO. In particular, this approach has been used to obtain white emitting LEDs.
[1] J. Pereira, J. Farinhas, J. Morgado, Materials Letters 175, 248 (2016).
Acknowledgments: We thank FCT Portugal for financial support under the contract UID/EEA/50008/2013 and for a PhD grant to Joana Farinhas