Discipline: Chemistry and Chemical Sciences
Subcategory: Materials Science
Session: 1
Room: Exhibit Hall
David Diaz - University of North Carolina at Charlotte
Co-Author(s): Abhishek Shibu, UNC-Charlotte, NC; Pranamita Chakraborti, UNC-Charlotte, NC; Olivia Mikula UNC-Charlotte, NC; Dr. Michael G. Walter UNC-Charlotte, NC
Blue light emitting materials are notorious for being unstable due to their wide bandgap.1 The manner by which people connect with this material is through OLEDs found in digital devices, cell phones, TVs, or computer screens. It can likewise be found in numerous clinical applications like phototherapeutics, which treats illnesses with various light sources like lasers, UV/IR radiation, and LEDs. Currently, most of industry utilizes rare earth element (REE) containing material to create these stable blue light emitting diodes (LEDs) thanks to the Nobel Prize winning work of Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura.1 However, with the concern of planet preservation, REE containing materials are scrutinized for the carbon footprint left by its extraction and purification process. I seek to tackle this issue with thiazolothiazole (TTz) systems; They do not contain REEs, are easy and cheap to synthesize, and most importantly are under explored in terms of blue light emitting research. An array of symmetric donor-acceptor-donor TTz and asymmetric push-push TTz dyes were studied as polymer processed systems and organic aggregates. These systems were studied for their optical properties using UV-vis, solid-state photoluminescence spectroscopy and time resolved emission spectroscopic methods. An integrating sphere was used to measure fluorescence quantum yield in the solid state. For all our TTz compounds it was found adding more polymer to a TTz dye will blueshift the peak emission wavelength. For example, when comparing a 10:90 percent (dye:polymer) loaded substrate to a 1:99 percent loaded substrate, there was a 26 nm blueshift in peak emission for the dibutyl ester TTz compound. It is hypothesized that in solution the TTz compound aggregates and limits its emission intensity. In polymer, this aggregation is kept to a minimum which could be how other compounds like diphenyl ester TTz have such high experimental quantum yields of up to 97.3 ± 0.9 and average lifetimes of up to 1756.9 ps. The radiative rate of the TTz dyes in polymer and solvents will be compared to test the practicality of TTz dyes in polymer. Other future research will focus on the applications of TTz dyes in other polymers such as poly(styrene), PMMA, SBS and many others. Prospective applications of the dye in 3D printing polymer filaments will also be explored.2 Properly cataloging an array of stable blue emitters contributes to the future growth of new technologies that will benefit from the easily processable, environmentally sustainable, and inexpensive solutions provided by TTz systems.References: 1.Lee, J.-H et al. Blue Organic Light-Emitting Diodes: Current Status, Challenges, and Future Outlook. J. Mater. Chem. C 2019, 7 (20), 5874–5888. https://doi.org/10.1039/C9TC00204A.2.Gastaldi, Matteo et al. Functional Dyes in Polymeric 3D Printing: Applications and Perspectives. ACS Materials Letters 2021 3 (1), 1-17 DOI:10.1021/acsmaterialslett.0c00455
Funder Acknowledgement(s): The author(s) would like to acknowledge the NC-LSAMP SPRA program, which was funded through NSF Award #2010124
Faculty Advisor: Michael G. Walter, mwalte33@uncc.edu
Role: Making of dye/polymer thin films, optical measurements and calculations such emission/excitaiton spectra, solid state quantum yield, average lifetime, and radiative rate.