Three-Dimensional Spirothienoquinoline-Based Small Molecules for Organic Photovoltaic and Organic Resistive Memory Applications

作者：Li, Panpan; Chan, Chin-Yiu; Lai, Shiu-Lun; Chan, Hing; Leung, Ming-Yi; Hong, Eugene Yau-Hin; Li, Jingwen; Wu, Hongbin; Chan, Mei-Yee^*; Yam, Vivian Wing-Wah^*

来源：ACS applied materials & interfaces, 2020, 12(10): 11865-11875.

DOI：10.1021/acsami.9b19746

• spirothienoquinoline
• benzochalcogenodiazole
• bulk heterojunction
• organic solar cells
• organic resistive memory

A new electron-rich spirothienoquinoline unit, (t)BuSAF-Th, has been developed via incorporation of a thienyl unit instead of a phenyl unit into the six-membered ring of the spiroacridine (SAF) and utilized for the first time as a building block for constructing small-molecule electron donors in organic solar cells (OSCs) and as active layers in organic resistive memory devices. The resulting three-dimensional spirothienoquinoline-containing 1-4 exhibit high-lying highest occupied molecular orbital (HOMO) energy levels. By the introduction of electron-deficient benzochalcogenodiazole linkers, with the chalcogen atoms being varied from O to S and Se, a progressively lower lowest unoccupied molecular orbital (LUMO) energy level has been achieved while keeping the HOMO energy levels similar. This strategy has allowed an enhanced light-harvesting ability without compromising open-circuit voltage (V-oc) in vacuum-deposited bulk heterojunction OSCs using 1-4 as donors and C-70 as the acceptor. Good photovoltaic performances with power conversion efficiencies (PCEs) of up to 3.86% and high short-circuit current densities (J(sc)) of up to 10.84 mA cm(-2) have been achieved. In addition, organic resistive memory devices fabricated with these donor-acceptor small molecules exhibit binary logic memory behaviors with long retention times and high on/off current ratios. This work indicates that the spirothienoquinoline moiety is a potential building block for constructing multifunctional organic electronic materials.