Abstract
Deoxyribonucleic acid (DNA) biopolymers have been considered as a promising material applied in various optoelectronic devices. Since carrier transport highly relates to performance of these DNA-based devices, our goal is to investigate the carrier mobility of DNA biopolymers. In this thesis, we present the hole mobility characterization of cetyltrimethylammonium(CTMA)-modified DNA biopolymer by using space-charge-limited current (SCLC) analysis. A trap-free SCLC behavior and quadratic dependence were achieved in the current-voltage characteristics. The correlation between the mobility and electric field was studied. A positive thickness dependence of the mobility was also demonstrated. Temperature dependency in DNA biopolymer was later examined as well. To further improve the conductivity of DNA biopolymer, we reported the use of aromatic surfactants to modify DNA molecules instead of the previously commonly-used CTMA. The aromatic-based DNA biopolymers were employed in organic light-emitting devices (OLEDs). Enhanced luminance and efficiency were accomplished compared to devices without the biopolymer layer, ascribed to a more efficient carrier recombination. The biopolymer was expected to act as an electron blocking layer and a buffer layer between the hole transporting and the emitting material. Improved performance was also achieved compared to the OLEDs incorporated with DNA-CTMA, verifying the advantage of using aromatic surfactants to synthesize DNA biopolymers. The results show a facile route to tailor the conductivity of DNA biopolymers, providing a promising future of incorporating DNA biopolymers in optoelectronic applications.