Ultrafast and Sensitive Self-Powered Photodetector Featuring Self-Limited Depletion Region and Fully Depleted Channel with van der Waals Contacts

Self-powered photodetectors with great potential for implanted medical diagnosis and smart communications have been severely hindered by the difficulty of simultaneously achieving high sensitivity and fast response speed. Here, we report an ultrafast and highly sensitive self-powered photodetector based on two-dimensional (2D) InSe, which is achieved by applying a device architecture design and generating ideal Schottky or ohmic contacts on 2D layered semiconductors, which are difficult to realize in the conventional semiconductors owing to their surface Fermi-level pinning. The as-fabricated InSe photodiode features a maximal lateral self-limited depletion region and a vertical fully depleted channel. It exhibits a high detectivity of 1.26 × 1013 Jones and an ultrafast response speed of ∼200 ns, which breaks the response speed limit of reported self-powered photodetectors based on 2D semiconductors. The high sensitivity is achieved by an ultralow dark current noise generated from the robust van der Waals (vdW) Schottky junction and a high photoresponsivity due to the formation of a maximal lateral self-limited depletion region. The ultrafast response time is dominated by the fast carrier drift driven by a strong built-in electric field in the vertical fully depleted channel. This device architecture can help us to design high-performance photodetectors utilizing vdW layered semiconductors

Dual-responsive and controlled-release paclitaxel-loaded mesoporous silicon nanoparticles with cell membrane coating for homologous targeted therapy of tongue squamous cell carcinoma

The application of paclitaxel (PTX) for chemotherapy of tongue squamous cell carcinoma shows unavoidable damage to normal tissue, thus need to develop drug delivery and tumor-targeting nanomaterials. Mesoporous silica nanoparticles (MSNs) exhibit advantages including a convenient synthesis process, adjustable structure, high drug loading efficiency and low cytotoxicity. In this study, we synthesized PTX-loaded calcium carbonate-coated degradable disulfide-doped MSNs to construct a pH/redox dual-responsive controlled-release nanosystem. A high PTX loading rate of 9.68 ± 0.21% was measured with significantly accelerated release at low pH and in the presence of GSH. Moreover, surface decoration of the cell membrane was conducted to realize homologous targeted killing of tongue squamous cell carcinoma cells (PTX/ssMSN@CaCO3@TC), as confirmed by dynamic light scattering and gel electrophoresis analyses. Our nanocomposite material could be effectively taken up by Tca8113 cells but not by L929 and HeLa cells. Moreover, excellent tumor killing performance was measured both in vitro and in vivo. A total of 94.00 ± 1.66% and 98.12 ± 0.28% of Tca8113 cells were killed after culturing for 1 day and 3 days, respectively. This study developed a novel nanomaterial with the abilities of homologous targeting and dual-responsive release of PTX in tumor cells, exhibiting great value for the design of nanotargeting tumor killing drugs