Hava Akpinar

Natural resin shellac as a substrate and a dielectric layer for organic field-effect transistors

Biocompatible and sustainable electronic-grade materials are integral for the development of electronics for biointegration and ‘use-and-throw’ applications. Herein we report the use of the natural resin shellac in organic field-effect transistors. Shellac was employed to cast robust and smooth substrates suitable for durable transistor devices. In addition shellac displays excellent insulating properties enabling its use as a high-quality dielectric layer for organic field-effect transistor (OFET) devices. We demonstrate that two common organic semiconductors, pentacene and C60, show hysteresis-free operation in OFETs that employ shellac both as the substrate and as dielectric material. Shellac is a fully biocompatible (even edible) material that offers many advantages for OFET fabrication, including high dielectric breakdown fields, simple solution processing from ethanol solutions, and low temperature crosslinking at 50–70 °C. This work shows that shellac as a biomaterial can enable OFET applications where biocompatibility is necessary.

A novel DAD type and folic acid conjugated fluorescent monomer as a targeting probe for imaging of folate receptor overexpressed cells

We describe a modification and post‐functionalization technique for a donor–acceptor–donor type monomer; 6‐(4,7‐bis(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐5‐yl)‐2H‐benzo[d][1,2, 3]triazol‐2‐yl)hexan‐1‐amine. Folic acid was attached to the fluorescent structure. The conjugation was confirmed via NMR and Fourier transform infrared analyses. Cytotoxicity was investigated and the comparison of association of targeted monomeric structures in tumor cells was monitored via fluorescence microscopy.