Solid state photon upconversion utilizing thermally activated delayed fluorescence molecules as triplet sensitizer

The ability to upconvert light is useful for a range of applications, from biological imaging to solar cells. But modern technologies have struggled to upconvert incoherent incident light at low intensities. Here, we report solid state photon upconversion employing triplet-triplet exciton annihilati...

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Bibliographic Details
Main Authors: Wu, Tony C, Congreve, Daniel Norbert, Baldo, Marc A
Other Authors: Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Format: Article
Published: AIP Publishing 2018
Online Access:http://hdl.handle.net/1721.1/117851
https://orcid.org/0000-0003-3005-9831
https://orcid.org/0000-0002-2914-3561
https://orcid.org/0000-0003-2201-5257
Description
Summary:The ability to upconvert light is useful for a range of applications, from biological imaging to solar cells. But modern technologies have struggled to upconvert incoherent incident light at low intensities. Here, we report solid state photon upconversion employing triplet-triplet exciton annihilation in an organic semiconductor, sensitized by a thermally activated-delayed fluorescence (TADF) dye. Compared to conventional phosphorescent sensitizers, the TADF dye maximizes the wavelength shift in upconversion due to its small singlet-triplet splitting. The efficiency of energy transfer from the TADF dye is 9.1%, and the conversion yield of sensitizer exciton pairs to singlet excitons in the annihilator is 1.1%. Our results demonstrate upconversion in solid state geometries and with non-heavy metal-based sensitizer materials.