Photochemical Sciences Ph.D. Dissertations

Title

Synthesis and Characterizations of Bis-diazirines and Their Applications in Organic Electronics

Date of Award

2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Photochemical Sciences

First Advisor

Pavel Anzenbacher, Jr. (Advisor)

Second Advisor

Malcolm Forbes (Committee Member)

Third Advisor

Joseph Furgal (Committee Member)

Fourth Advisor

Jeffrey Meyer (Committee Member)

Abstract

Large area organic electronics are multilayer devices fabricated by solution processing of different organic semiconductor molecules. However, the main challenges for the solution processing techniques are the erosion of the previously deposited layer by the solvents used for the subsequent layer deposition, interfacial mixing, and formation of uneven interfaces and surfaces, all of which significantly reduce the device performance. Herein we demonstrate a photopolymerizable bis-diazirine-based crosslinker molecule capable of converting soluble organic materials into highly cross-linked insoluble networks, alleviating the inter-layer mixing problems. Upon 5-20 min irradiation with long wavelength/low power UV (1.8 mW/cm2) bis-diazirines results in the formation of carbenes that react via carbon-hydrogen bond insertion with polymers or small-molecules yielding cross-linked networks. This photo-generated crosslinking does not require any catalyst, initiator, or short-wavelength UV light and is performed at room temperature, releasing molecular nitrogen as the only byproduct. To study the effectiveness of bis-diazirine-mediated photo-crosslinking in this dissertation we have described the design, synthesis, and characterization of the bis-diazirine crosslinker molecules, studied their photochemical and photophysical properties, fabricated functional OLED devices and finally, evaluation of the OLEDs performance.

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