Low Refractive Index OLEDs for Practical High Efficiency Outcoupling

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Lead Performer: Pennsylvania State University – University Park, PA
Partners:

  • OLEDWorks, LLC – Rochester, NY

DOE Total Funding: $1,150,345
Project Term: April 17, 2019 – April 16, 2021
Funding Type: SSL R&D Funding Opportunity Announcement (FOA) (DE-FOA-0001823)

Project Objective

Improved optical outcoupling is arguably the last major opportunity to increase the efficiency of OLED lighting. While good solutions exist to scatter light out from the substrate into air, internal light extraction from the OLED stack into the substrate has proven to be more difficult without compromising long-term reliability, manufacturability, and cost. To be both effective and commercially viable, internal light extraction approaches must be inexpensive and noninvasive in the device stack while eliminating the large number of guided modes that exist in the organic layers of thick, multi-unit commercial OLED lighting panels. This project will leverage the interdisciplinary expertise of Penn State University and OLEDWorks, LLC, to develop a general pathway to lower the refractive index of existing OLED materials via a strategy known as semiconductor dilution. The team will develop and test a series of electrically inert dilution molecules that can be co-deposited together with electron and hole transport materials to significantly reduce their refractive index without compromising electrical transport or morphological stability.

Project Impact

Implementing these low-index transport layers in commercial multi-stack OLEDs will eliminate the existence of guided modes in the organic stack, significantly increasing internal light extraction into the substrate and providing a path to reach DOE’s outcoupling efficiency target for 2025.

Contacts

DOE Technology Manager: Brian Walker, brian.walker@ee.doe.gov  
Lead Performer: Chris Giebink, Pennsylvania State University