Molybdenum disulfide (MoS ), a typical 2D metal dichalcogenide (2DMD), has exhibited tremendous potential in optoelectronic device applications, especially in photodetection. However, due to the weak light absorption of planar mono-/multilayers, limited cutoff wavelength edge, and lack of high-quality junctions, most reported MoS -based photodetectors show undesirable performance. Here, a structurized 3D heterojunction of RGO-MoS /pyramid Si is demonstrated via a simple solution-processing method. Owing to the improved light absorption by the pyramid structure, the narrowed bandgap of the MoS by the imperfect crystallinity, and the enhanced charge separation/transportation by the inserted reduced graphene oxide (RGO), the assembled photodetector exhibits excellent performance in terms of a large responsivity of 21.8 A W , extremely high detectivity up to 3.8 × 10 Jones (Jones = cm Hz W ) and ultrabroad spectrum response ranging from 350 nm (ultraviolet) to 4.3 µm (midwave infrared). These device parameters represent the best results for MoS -based self-driven photodetectors, and the detectivity value sets a new record for the 2DMD-based photodetectors reported thus far. Prospectively, the design of novel 3D heterojunction can be extended to other 2DMDs, opening up the opportunities for a host of high-performance optoelectronic devices.
Owing to their unique nanosize effect and surface effect, pseudocapacitive quantum dots (QDs) hold considerable potential for high‐efficiency supercapacitors (SCs). However, their pseudocapacitive behavior is exploited in aqueous electrolytes with narrow potential windows, thereby leading to a low energy density of the SCs. Here, a film electrode based on dual‐confined FeOOH QDs (FQDs) with superior pseudocapacitive behavior in a high‐voltage ionic liquid (IL) electrolyte is put forward. In such a film electrode, FQDs are steadily dual‐confined in a 2D heterogeneous nanospace supported by graphite carbon nitride (g‐C3N4) and Ti‐MXene (Ti3C2). Probing of potential‐driven ion accumulation elucidates that strong adsorption occurs between the IL cation and the electrode surface with abundant active sites, providing sufficient redox reaction of FQDs in the film electrode. Furthermore, porous g‐C3N4 and conductive Ti3C2 act as ion‐accessible channels and charge‐transfer pathways, respectively, endowing the FQDs‐based film electrode with favorable electrochemical kinetics in the IL electrolyte. A high‐voltage flexible SC (FSC) based on an ionogel electrolyte is fabricated, exhibiting a high energy density (77.12 mWh cm−3), a high power density, a remarkable rate capability, and long‐term durability. Such an FSC can also be charged by harvesting sustainable energy and can effectively power various wearable and portable electronics.
Electron injection plays a crucial role in arousing the double‐slope characteristics for p‐type organic field‐effect transistors (OFETs) with narrow‐bandgap organic semiconductors (OSCs). This issue will not only result in the misrepresentation of OFET performance but also may cause device instability, hence impeding their further development in real‐world applications. A facile and highly efficient approach is developed to circumvent this issue by implementing modification on the electrode/organic semiconductor interface. An ultrathin layer of wide‐bandgap OSC with suitable energy levels is introduced to block the undesirable electron injection. By this means, typical double‐slope behaviors and bias stress stability in the p‐type OFETs can be significantly improved. Using 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl) anthradithiophene‐based OFETs the double‐slope behaviors of as‐fabricated devices are effectively converted to near‐ideal behaviors after modification, leading to a dramatic improvement of average reliability from 65.11% to 91.76%. Furthermore, the positive drift of transfer curves under prolonged bias stress is also successfully suppressed. This strategy demonstrates good universality and can provide a new guideline for the fabrication of OFETs with ideal behaviors.
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