π‐Conjugated Molecules Crosslinked Graphene‐Based Ultrathin Films and Their Tunable Performances in Organic Nanoelectronics

Graphene-based ultrathin films with tunable performances, controlled thickness, and high stability are crucial for their uses. The currently existing protocols, however, could hardly simultaneously meet these requirements. Using amino-substituted π-conjugated compounds, including 1,4-diaminobenzene (DABNH2), benzidine (BZDNH2), and 5,10,15,20-tetrakis (4-aminophenyl)-21H,23H-porphine (TPPNH2), as cross-linkages, a new protocol through which graphene oxide (GO) nanosheets can be anchored on solid supports with a high stability and controlled thickness via a layer-by-layer method is presented. A thermal annealing leads to the reduction of the films, and the qualities of the samples can be inherited by the as-produced reduced GO films (RGO). When RGO films are integrated as source/drain electrodes in OFETs, tunable performances can be realized. The devices based on the BZDNH2-crosslinked RGO electrodes exhibit similar electrical behaviors as those based on the non-π-conjugated compound crosslinked electrodes, while improved performances can be gained when those crosslinked by DABNH2 are used. The performances can be further improved when RGO films crosslinked by TPPNH2 are employed. This work likely paves a new avenue for graphene-based films of tunable performances, controlled thickness, and high stability.