Colloidal Quantum Dot Light-Emitting Diodes Employing Phosphorescent Small Organic Molecules as Efficient Exciton Harvesters

Evren Mutlugun; Burak Guzelturk; Agus Putu Abiyasa; Yuan Gao; Xiao Wei Sun; Hilmi Volkan Demir

doi:10.1021/jz5012669

Colloidal Quantum Dot Light-Emitting Diodes Employing Phosphorescent Small Organic Molecules as Efficient Exciton Harvesters

J Phys Chem Lett. 2014 Aug 21;5(16):2802-7. doi: 10.1021/jz5012669. Epub 2014 Aug 4.

Authors

Evren Mutlugun^{1

2

3}, Burak Guzelturk^{1

3}, Agus Putu Abiyasa³, Yuan Gao³, Xiao Wei Sun³, Hilmi Volkan Demir^{1

3}

Affiliations

¹ †Department of Electrical and Electronics Engineering, Department of Physics, UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800, Turkey.
² ‡Electrical-Electronics Engineering, Abdullah Gul University, Kayseri, Turkey TR-38039.
³ §Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Materials Sciences, Nanyang Technological University, Singapore 639798, Singapore.

PMID: 26278082
DOI: 10.1021/jz5012669

Abstract

Nonradiative energy transfer (NRET) is an alternative excitation mechanism in colloidal quantum dot (QD) based electroluminescent devices (QLEDs). Here, we develop hybrid highly spectrally pure QLEDs that facilitate energy transfer pumping via NRET from a phosphorescent small organic molecule-codoped charge transport layer to the adjacent QDs. A partially codoped exciton funnelling electron transport layer is proposed and optimized for enhanced QLED performance while exhibiting very high color purity of 99%. These energy transfer pumped hybrid QLEDs demonstrate a 6-fold enhancement factor in the external quantum efficiency over the conventional QLED structure, in which energy transfer pumping is intrinsically weak.

Keywords: colloidal quantum dots; hybrid light-emitting diodes; nonradiative energy transfer; phosphorescent molecules; triplet state harvesting.