OLED outcoupling efficiency is limited by several factors, one major factor is the limitation caused by internal reflection of light with the interface between organic layers including the anode and glass substrate. Here, we approach this problem by adding a fairly exotic material to the OLED setup, which strongly scatters light. We expect the scattering to weaken total internal reflection and increase outcoupling efficiency. Through measurements, we compare the out coupling efficiency of the control OLEDs and the OLEDs with the scattering layer. Finally, we analyze the potential for increased outcoupling efficiency and, later, industrial application. After analysis we find a 1-2% increase in efficiency without accounting for error.

One challenge in the development of ferroelectric liquid crystal (LC) display materials^1,2 is the presence of defects attributed to smectic layer contraction on cooling from the smectic A phase to the smectic C phase during alignment. Though some materials exist which do not exhibit such defects (DeVries materials), an understanding of which structural features favor such properties is not yet available. Our group has discovered several LC mesogens containing sulfur-based moieties that do not possess these problematic defects. In this study, our goal is to synthesize several structural variants of a LC family containing a thieno[3,2-b]thiophene ring (1) within the LC core to determine how structural changes impact mesogenic behavior. Preliminary studies by another group member targeted some thieno[3,2-b]thiophene-based LCs, though in only low yields.² In this project, we hope to synthesize several of these LC targets in sufficient yields for evaluation of their mesogenic behavior.

The synthesis of these compounds uses a new approach for 2-alkoxythiophene synthesis recently developed in our laboratories (Scheme 1).² Thienone 6 was prepared in four steps from commercial materials. Mitsunobu etherification using 1-octanol yields compound 7. Compound 7 is deprotonated with LDA and treated with N-formylpiperidine followed by hydrolysis to give the aldehyde 8, which reacts with ethyl mercaptoacetate (9) in the presence of base to produce the thieno[3,2-b]thiophene ester 10. The final targeted mesogens 13 (Scheme 2) will be prepared via saponification of 10 to the carboxylic acid 11 followed by esterification with a variety of chiral and achiral 4-alkoxyphenols 12.

References:

(1) Beekman, J.; Neyts, K.; Vanbrabant, P. J. M. Opt. Eng. 2011, 50, 081202-081217

(2) (a) Tietz, J. I., M.S. Thesis, Kent State University, Kent, OH, 2012. (b) Tietz, J.I.; Seed, A.J.;

Sampson, P. Org. Lett. 2012, 14, 5058-5061.

Nitroxyl (HNO) is a biologically relevant small molecule with considerable clinical promise for the treatment of heart failure. However, studies of the chemistry and biology of nitroxyl are hampered by its short lifetime in aqueous solution. To aid in biological and chemical studies, various nitroxyl donors (molecules that degrade to release HNO) have been synthesized. Our group’s focus is on the synthesis of nitroxyl donors that rapidly release HNO under physiological conditions through photoactivation of a pendent 3-hydroxy-2-naphthyl methyl (3,2-HNM) group. First generation 3,2-HNM-based HNO donor 1 released HNO upon photoactivation, but competition was also observed from a redox side reaction. In this study, we are probing the impact of a methyl substituent at C* (2) on these competing processes. Difficulty in the synthesis of key alkoxylamine intermediate 3 has led to studies of variant Mitsunobu reactions that might be suitable for the efficient synthesis of 3. Ongoing studies involve use of various N-hydroxyphthalimide nucleophiles and applying differnet protecting groups (PG) in the key Mitsunobu step. This poster will present progress made to date on the Mitsunobu step leading to 3 and its elaboration to the final target 2.

Not available at this time.

Graphene is a material that promises much technologic advancement, from more efficient solar cells to higher capacity batteries. Currently the use of graphene is limited due to the difficulty of obtaining large pure sheets. Graphene oxide is similar to graphene except oxygen-containing functional groups are attached to the carbon lattice. Graphene oxide is easier to synthesize than graphene; however, the functional groups reduce the electrical conductivity of the material. If these groups could be partially or fully removed from graphene oxide the material would have properties closer to those of graphene. This process of removing oxygen groups is known as reduction and the final product is aptly called reduced graphene oxide. We aim at investigating if radiation from an electron beam accelerator could reduce graphene oxide. Samples of pre-prepared graphene oxide solution (from Graphene Supermarket Inc. USA) were deposited on glass slides partially coated in Indium tin oxide. After being dried, the samples were irradiated in the dose interval from 100 kGy to 1.6 MGy, using an electron beam accelerator at energies 80 keV and 120 keV. The samples were tested using Fourier transform infrared spectroscopy to determine any structural changes induced by the radiation, paying special attention to the absorbance peaks corresponding to carboxyl (-COOH) and alcohol (-OH) functional groups as well as the sp² hybridized Carbon-Carbon bond. Four-probe resistivity measurements were later performed to determine the sheet resistance of the samples and characterize the conductivity changes caused by the radiation.