Improving the rectifying performance of the pyrene-benzene system by optimizing its hydrocarbon bridge: A first-principles investigation

We report a computational study on enhancing the rectification ratio (RR) of the pyrene-benzene junction by modifying the structure of its acyclic aliphatic hydrocarbon bridge. The RR values for a series of pyrene-benzene systems with different types of bridges are determined. Notably, the maximum RR of the pyrene-(CH)3-(CH2)3-(CH)3-benzene system is 93.8, and the same hydrocarbon bridge increases the RR of the organic photovoltaic materials pyrene-DMA (N,N-dimethylaniline) and pyrene-DCNB (p-dicyanobenzene) by 10 times and limits reverse current during photo-induced electron transfer. These findings are particularly important for the design of molecular devices where both a high RR and conductivity are desirable. Moreover, they provide new insight into phenomena that indirectly affects the photoelectric conversion efficiency viz. enhancing the RR of the materials.