Photoconductance from the Bent-to-Planar Photocycle between Ground and Excited States in Single-Molecule Junctions

• DOI: 10.1021/jacs.2c03671
• Publication Date: 2022-05-25T10:47:26Z
• Authors: Qi Zou; Xuanying Chen; Yu Zhou; Xin Jin; Zhiyun Zhang; Jin Qiu; Rui Wang; Wenjing Hong; Jianhua Su; Da-Hui Qu; He Tian
• Keywords: Nanotechnology; Electronics; 01 natural sciences; 0104 chemical sciences

Single-molecule conductance measurements for 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (DPAC) may offer unique insight into the bent-to-planar photocycle between ground and excited states. Herein, we employ DPAC derivative DPAC-SMe as molecular prototype to fabricate single-molecule junctions using scanning tunneling microscope break junction technique explore photoconductance dependence on excited-state structural/electronic changes. We find up ∼200% enhancement of under continuous 340 nm light irradiation than that without irradiation, while disappears in case where structural evolution is halted through macrocyclization. The situ modulation pulsed monitored DPAC-SMe-based alone, suggesting stems from photoinduced intramolecular planarization. Theoretical calculations reveal brings about a significant redistribution electron cloud density, which leads appearance Fano resonance, resulting enhanced DPAC-SMe-fabricated junctions. This work provides evidence photocycle-induced differences at level, offering tailored approach tuning charge transport characteristics organic photoelectronic devices.