White polymer light emitting diode using blend of fluorescent polymers

Asit Prakash; Monica Katiyar

doi:10.1117/12.928008

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15 October 2012 White polymer light emitting diode using blend of fluorescent polymers

Asit Prakash, Monica Katiyar

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Proceedings Volume 8549, 16th International Workshop on Physics of Semiconductor Devices; 854938 (2012) https://doi.org/10.1117/12.928008
Event: 16th International Workshop on Physics of Semiconductor Devices, 2011, Kanpur, India

Abstract

Publisher’s Note: This paper, originally published on 10 October 2012, was replaced with a revised version on 22 July 2016. If you downloaded the original PDF, but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. White polymer light emitting diodes (WPLEDs) are fabricated using poly(9,9-dioctylﬂuorene-2,7-diyl) (PFO) as host andpoly [2-methoxy-5-(2’-ethyl-hexyloxy)]-1,4-phenylene vinylene (MEH-PPV) as guest material having structure ITO(150nm)/PEDOT:PSS(40nm)/PFO:MEH-PPV(~ 68nm)/Ca(20nm)/Al(120nm). Photoluminescence spectra of blends with different MEH-PPV concentration reveal that at low doping level of MEH-PPV, blue emission from PFO and yellow emission from MEH-PPV co-exist due to incomplete energy transfer from PFO to MEH-PPV. Surface morphology of the spin coated blend films with different concentrations of MEH-PPV were studied using atomic force microscopy (AFM). It shows segregation/agglomeration of polymers at higher concentration of MEH-PPV (~8.0 wt %). Finally, WPLEDs, having MEH-PPV in the range of 2.0-8.0 wt%, were fabricated. We obtained best device at 2.0 wt% of MEH-PPV, it shows white light with Commission Internationale de l’Enclairage (CIE) coordinate of (0.30, 0.38). Electroluminescence turn-on voltage of the device was 4.0 V and maximum luminance reaches 1234 cd/m2 at 8.5 V. The luminous current and power efficiency at current density of 22 mA/cm2 were found to be 2.0 cd/A and 1.1 lm/W, respectively.

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Asit Prakash and Monica Katiyar "White polymer light emitting diode using blend of fluorescent polymers", Proc. SPIE 8549, 16th International Workshop on Physics of Semiconductor Devices, 854938 (15 October 2012); https://doi.org/10.1117/12.928008

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