Organic heterojunction charge-transfer chemical sensors

Abstract

Chemical sensors based on organic semiconductors are targeted for diverse applications due to their ease of manufacturing and mechanical flexibility. However, they often rely on an increase in resistance, or require implementation into a transistor configuration, which increases device complexity and can give them a background signal that ultimately limits their sensitivity. We present an amine sensing n-type organic semiconducting film that employs only a two-electrode configuration and relies on an increase in device conductivity. Devices employ a mixture of sensitizing and transporting components and achieve an increase in conductivity from an electron transfer reaction from the sensitizer to the n-type semiconductor. The sensors exhibit a 104% change in conductivity when exposed to butylamine vapor at 500 parts per trillion, demonstrating a path forward toward broadly applicable, printable chemical sensors that outperform the olfactory response of canines.