CHARGE INJECTION CONTACTS IN ORGANIC SEMICONDUCTOR DEVICES

Abstract

ORGANIC SEMICONDUCTOR DEVICES COMPRISE ONE OR MORE ORGANIC SEMICONDUCTOR LAYERS ADJACENT TO CHARGE-INJECTION AND EXTRACTION CONTACTS. THIS THESIS FOCUSES ON DEVELOPING NEW UNDERSTANDING TO ACHIEVE BETTER CHARGE INJECTION CONTACTS. I STUDIED THE PROPERTIES OF A NEW HIGHLY-STABLE P-DOPED CONDUCTING POLYMER BLEND, POLY(3-METHOXYETHOXYETHOXYTHIOPHENE):POLY(4-HYDROXYSTYRENE) (S-P3MEET:PHOST) AND NEW P-DOPED CONDUCTING POLYMER BLENDS FORMULATED WITH PERFLUORINATED IONOMERS (PFIS), DEMONSTRATING THE RESILIENCE OF S-P3MEET:PHOST TO INJECTION-INDUCED DEDOPING WHICH LEADS TO CONDUCTIVITY FADING IN POLY(3,4-ETHYLENEDIOXYTHIOPHENE):POLY(STYRENESULFONIC ACID) (PEDT:PSSH). I ALSO SHOWED THAT WHILE SURFACE-SEGREGATION OF PFI CAN INCREASE WORKFUNCTION IN THE BLENDS, USING PEDT: PSSH: PFI AS MODEL, THIS DOES NOT ALWAYS BENEFIT HOLE INJECTION BECAUSE OF THE RESISTANCE ASSOCIATED WITH THE MOLECULARLY-THIN PFI OVERLAYER. I ALSO STUDIED THE SYSTEMATIC ?TUNING? OF THE WORKFUNCTION OF STABLE CU METAL AND I