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Formation and Photodynamic Behavior of Transition Metal Dichalcogenide Nanosheet–Fullerene Inorganic/Organic Nanohybrids on Semiconducting Electrodes

2017; Wiley; Volume: 24; Issue: 7 Linguagem: Inglês

10.1002/chem.201703699

1521-3765

Jinseok Baek, Tomokazu Umeyama, Wookjin Choi, Yusuke Tsutsui, Hiroki Yamada, Shu Seki, Hiroshi Imahori,

Perovskite Materials and Applications

Abstract Composite films that consisted of C 60 and well‐exfoliated nanosheets of transition metal dichalcogenides (TMDs), such as MoS 2 or WS 2 , with a bulk heterojunction structure were easily fabricated onto a semiconducting SnO 2 electrode via a two‐step methodology: self‐assembly into their composite aggregates by injection of a poor solvent into a good solvent with the dispersion, and subsequent electrophoretic deposition. Upon photoexcitation, the composites on SnO 2 exhibited enhanced transient conductivity in comparison with single components of TMDs or C 60 , which demonstrates that the bulk heterojunction nanostructure of TMD and C 60 promoted the charge separation (CS). In addition, the decoration of the TMD nanosheets with C 60 hindered the undesirable charge recombination (CR) between an electron in SnO 2 and a hole in the TMD nanosheets. Owing to the accelerated CS and suppressed CR, photoelectrochemical devices based on the MoS 2 –C 60 and WS 2 –C 60 composites achieved remarkably improved incident photon‐to‐current efficiencies (IPCEs) as compared with the single‐component films. Despite more suppressed CR in WS 2 –C 60 than MoS 2 –C 60 , the IPCE value of the device with WS 2 –C 60 was smaller than that with MoS 2 –C 60 owing to its inhomogeneous film structure.