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Precharged Interface MAFA UC Manuscript.pdf (1.04 MB)
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Precharging Photon Upconversion: Interfacial Interactions in Solution-Processed Perovskite Upconversion Devices

preprint
submitted on 05.12.2019 and posted on 16.12.2019 by Sarah Wieghold, Lea Nienhaus

Recent advances in perovskite-sensitized photon upconversion via triplet-triplet annihilation (TTA) in rubrene have yielded several unanswered questions about the underlying mechanism and processes occurring at the interface. In particular, the near-infrared perovskite emission is not significantly quenched and a rapid reversible photobleach of the upconverted emission can be observed under fairly low excitation densities of 3.2 mW/cm2. In this contribution, we investigate the perovskite/organic interface in more detail and conclude that non-covalent interactions between the organic layer and perovskite result in surface trap passivation. In addition, band bending results in a charge space region at the perovskite/rubrene interface, which precharges the rubrene interface with holes. Upon initial illumination, electrons can rapidly transfer to the excited triplet state of rubrene, followed by efficient TTA upconversion. As the device is continuously illuminated, the precharged holes are consumed and a new equilibrium is reached, resulting in the previously investigated steady-state upconversion efficiency.

History

Email Address of Submitting Author

lnienhaus@fsu.edu

Institution

Florida State University

Country

USA

ORCID For Submitting Author

0000-0003-1412-412X

Declaration of Conflict of Interest

No conflict of interest

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