Reversing the Conductance Evolution of Azobenzene Derivatives in Photoisomerization

Photoisomeric azobenzene derivatives with distinguished conductance in trans and cis states have gained extensive attention for their potential application in fabricating light-controlled electronic switches, which, however, faces great challenges due to the quenching effect once they are coupled to the electrode. Here, two kinds of azobenzene derivatives (TATA-TMA and TATA-TA) were synthesized by tethering a large TATA base, which increases the intermolecular distance and facilitates conformational changes, and by incorporating decoupling group into the molecular skeleton to insulate the azobenzene functional cores from electrode interactions. It is demonstrated that the conductance switch ratios of the synthesized molecules are enhanced by one order of magnitude. Interestingly, TATA-TMA and TATA-TA, although they have the same azobenzene core and TATA base, exhibit opposite conductance evolution trends during the photoisomerization process. Further elucidation of the underlying mechanism offers a logical routine for designing high-performance photoresponsive systems with controllable switching direction.