Controlled Growth of an Mo2CGraphene Hybrid Film as an Electrode in Self-Powered Two-Sided Mo2CGraphene/Sb2S0.42Se2.58/TiO2 Photodetectors

The monotonic work function of graphene makes it difficult to meet the electrode requirements of every device with different band structures. Two-dimensional (2D) transition metal carbides (TMCs), such as carbides in MXene, are considered good candidates for electrodes as a complement to graphene. Carbides in MXene have been used to make electrodes for use in devices such as lithium batteries. However, the small lateral size and thermal instability of carbides in MXene, synthesized by the chemically etching method, limit its application in optoelectronic devices. The chemical vapor deposition (CVD) method provides a new way to obtain high-quality ultrathin TMCs without functional groups. However, the TMCs film prepared by the CVD method tends to grow vertically during the growth process, which is disadvantageous for its application in the transparent electrode. Herein, we prepared an ultrathin Mo(2)Cgraphene (Mo(2)CGr) hybrid film by CVD to solve the above problem. The work function of Mo(2)CGr is between that of graphene and a pure Mo2C film. The Mo(2)CGr hybrid film was selected as a transparent hole-transporting layer to fabricate novel Mo(2)CGr/Sb2S0.42Se2.58/TiO2 two-sided photodetectors. The Mo(2)CGr/Sb2S0.42Se2.58/TiO2/fluorine-doped tin oxide (FTO) device could detect light from both the FTO side and the Mo(2)CGr side. The device could realize a short response time (0.084 ms) and recovery time (0.100 ms). This work is believed to provide a powerful method for preparing Mo(2)Cgraphene hybrid films and reveals its potential applications in optoelectronic devices.