Two-dimensional (2D) semiconductors play a crucial role in high-efficiency photocatalysts because of their high surface-to-volume ratio. The surface property is a key part of photocatalysis. In this work, the enhanced photocatalytic behavior of the layered ReS2 with optical polarization along the Re4 nano-diamond-chain (DC) direction (b axis) has been demonstrated. The unpolarized photoconductivity (PC) response of ReS2 with an applied bias along the b axis is approximately 1 order higher than that of the applied bias perpendicular to the b axis. The polarization-dependent PC spectra of E ∥ b also reveal a higher photoresponsivity with respect to those measured along the E ⊥ b polarization for the layered ReS2. This result indicates that stronger polarization dipoles as well as a larger amount of photogenerated carriers and surface states can contribute to the C-plane ReS2 under the illumination of E ∥ b polarized photons. With the special axial effect, the layered ReS2 2D photocatalyst shows much faster degradation rates of 5.6 and 12.3 than the other transition-metal dichalcogenides of TaS2 and MoS2 for the degradation of methylene blue (MNB) solution. For the polarization-dependent photodegradation test, the degradation rate of illuminated E ∥ b polarized photons is also approximately 12 times faster than that of the illuminated E ⊥ b polarized light in a 25 μM MNB solution. The enhanced photocatalytic behavior of ReS2 along the DC also shows a peak photoreponse of ∼25 μV detected in the polarized photovoltaic spectrum of the 0.5 μM MNB dye-sensitized solar cell positioned at ∼1.99 eV. The formation of a nano-DC and a one-layer trigonal crystalline phase is beneficial for the versatile energy applications of ReS2.

Structural, optical and photodetector properties of InS stripe-like crystals have been clearly demonstrated.

Wide band gap semiconductors are proper candidates for manufacturing UV‐visible electronic devices, photocatalysts and power electronic components. Among them, II–VI ZnS has a high flexibility in tuning energy range as compared to ZnO because of a larger bandgap about 3.7 eV. In this work, a high‐quality {111}‐oriented ZnS crystal of zinc‐blende structure has been successfully grown by chemical vapor transport method using I2 as the transport agent. High‐resolution transmission electron microscopy verifies its crystallinity and crystal orientation, and energy dispersive X‐ray analysis identifies its stoichiometry. Due to the coupling between crystal field and spin orbital in the high quality solid, three band‐edge excitonic transitions of EA=3.745, EB=3.799 and EC=3.881 eV have been detected. An initial metal‐semiconductor‐metal (MSM) Schottky photodiode made by {111}‐ZnS crystal has been assessed. The dark resistivity is about 6.13 MΩ‐cm. Under the irradiation of a 266‐nm laser (power ∼1.6 mW), the photo‐resistivity change (i. e., Δρ/ρdark) reaches 88%. Photo‐catalytic ability of the {111}‐ZnS single crystal was also evaluated using Methyl‐blue degradation. The degradation (normalized concentration change) after 1 hour can reach C/C0≈ 0.47 under irradiation of Xe‐arc lamp. All the experimental results reveal high responsivity of the {111}‐ZnS photodiode and good photocatalytic function of the {111}‐oriented crystal photocatalyst operated in the UV range.