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Photon upconversion in the solid state has the potential to improve existing solar and infrared imaging technologies due to its achievable efficiency at low power thresholds. However, despite considerable advancements in solution-phase upconversion, expanding the library of potential solid-state annihilators and developing a fundamental understanding of their solid-state behaviors remains challenging due to intermolecular coupling affecting the underlying energy landscape. Naphtho[2,3-a]pyrene has shown promise as a suitable solid-state annihilator. However, the origin of its multiple underlying emissive features remains unknown. To this point, here, we investigate NaPy/poly(methyl methacrylate) thin films at varying concentrations to tune the intermolecular coupling strength to determine its photophysical properties at a range of temperatures between 300–50 K. The results suggest that the multiple emissive features present in the NaPy thin film emission at room temperature arise from a multidimensional I-aggregate (520 nm), an excimer (550 nm), and a strongly coupled J-dimer (620 nm). In addition, we find that at low temperatures, the emission spectrum is dominated by direct emission from the 1(TT) state.
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Influence of Al2O3 Overlayers on Intermolecular Interactions between Metal Oxide Bound Molecules
Intermolecular interactions on inorganic substrates can have a critical impact on the electrochemical and photophysical properties of the materials and subsequent performance in hybrid electronics. Critical to the intentional formation or inhibition of these processes is controlling interactions between molecules on a surface. In this report, we investigated the impact of surface loading and atomic-layer-deposited Al2O3 overlayers on the intermolecular interactions of a ZrO2-bound anthracene derivative as probed by the photophysical properties of the interface. While surface loading density had no impact on the absorption spectra of the films, there was an increase in excimer features with surface loading as observed by both emission and transient absorption. The addition of ALD overlayers of Al2O3 resulted in a decrease in excimer formation, but the emission and transient absorption spectra were still dominated by excimer features. These results suggest that ALD may provide a post-surface loading means of influencing such intermolecular interactions.
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- Award ID(s):
- 1752782
- PAR ID:
- 10423538
- Date Published:
- Journal Name:
- Molecules
- Volume:
- 28
- Issue:
- 12
- ISSN:
- 1420-3049
- Page Range / eLocation ID:
- 4835
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/molecules28124835
