Co0.85Se hollow spheres constructed of ultrathin 2D mesoporous nanosheets as a novel bifunctional-electrode for supercapacitor and water splitting

Hollow spheres of Co0.85Se con structed by two-dime nsional(2D)mesoporous ultrathi nnanosheets were synthesized via simple and costeffective approach.Their bifunctional electrocatalytic-supercapacitive properties were obtained simultaneously due to synergistic effects betweenmacroscopic morphological features and microscopic atomic/electronic structure of Co0.85Se.The as-synthesized hollow spheres of Co0.85Sethat are con structed by 2D mesoporous ultrathin nanosheets exhibit in spiring electrochemical performance for supercapacitor,presenting maximum energy density at high power density(54.66 Wh·kg^-1 at 1.6 kW·kg^-1)and long cycle stability(88%retention after 8,000 cycles).Atthe same time,the hollow spheres of Co0.85Se constructed by 2D mesoporous ultrathin nanosheets display excellent catalytic performaneefor oxygen evolution reaction(OER)due to special structure,high surface area and mesoporous nature of sheets,which achieve lowoverpotential(290 mV at 10 mA·g^-1)and low Tafel slope(81 mV·dec^-1)for Iong-term operation(only 7.8%decay in current density after 9 h).It could be envisioned that the proposed simple approach will pave a new way to synthesize other metal chalcoge nides for energy conversionand storage technology.

Hybrid dual-channel phototransistor based on ID t-Se and 2D ReS2 mixed-dimensional heterostructures

The com bination of mixed-dimensional semiconducti ng materials can provide additional freedom to construct integrated n anoscale electronic and optoelectronic devices with diverse functionalities. In this work, we report a high-performanee dual-channel phototransistor based on one-dimensional (1D)/two-dimensional (2D) trigonal selenium (t-Se)/ReS2 heterostructures grown by chemical vapor deposition. The injection and separati on efficie ncy of photoge nerated electro n-hole pairs can be greatly improved due to the high-quality in terfacial con tact betwee n t-Se nano belts and ReS2 films. Compared with bare ReS2 film devices, the dual-cha nnel phototra nsistor based on t-Se/ReS2 heterostructure exhibits considerable enhancement with the responsivity (R) and detectivity (D^*) up to 98 A·W^-1 and 6 x 10^10 Jones at 400 nm illumination with an in tensity of 1.7 mW·cm^-2, respectively. Besides, the respo nse time can also be reduced by three times of magnitude to less than 50 ms due to the type-11 band alignment at the in terface. This study opens up a promising ave nue for high-performa nee photodetectors by constructing mixed-dimensional heterostructures.