Since the number of raw material selections for the synthesis of carbon dots (CDs) has grown extensively, herbal medicine as a precursor receives an increasing amount of attention. Compared with other biomass precursors, CDs derived from herbal medicine (HM-CDs) have become the most recent incomer in the family of CDs. In recent ten years, a great many studies have revealed that HM-CDs tend to be good at theranostics without drug loading. However, the relevant development and research results are not systematically reviewed. Herein, the origin and history of HM-CDs are outlined, especially their functional performances in medical diagnosis and treatment. Besides, we sort out the herbal medicine precursors, and analyze the primary synthetic methods and the key characteristics. In terms of the applications of HM-CDs, medical therapeutics, ion and molecular detection, bioimaging, as well as pH sensing are summarized. Finally, we discuss the crucial challenges and future prospects.

In the last decade, freestanding, single crystal silicon nanowires (SiNWs) have attracted significant attention as a potential material for low‐cost optoelectronic devices. In this paper, we demonstrate how strong localized surface plasmon modes, induced using silver nanoparticles, can be used to achieve significant improvement in a simple hybrid organic–inorganic photovoltaic device between n‐type silicon nanowires and poly(3,4‐ethylenedioxythiophene):poly‐(styrenesulfonate) (PEDOT:PSS). At photon energies above plasmon resonance, metallic nanoparticle‐induced absorption leads to a dramatic reduction of the reflectivity and we report a significant improvement in both the short circuit current density (Jsc) and the open circuit voltage (Voc). This leads to an overall 52% increase in the power conversion efficiencies (PCEs) of the photovoltaic devices when decorating the SiNWs with silver nanoparticles prior to PEDOT:PSS deposition.

The development of an electrically-conductive anticorrosion coating with self-healing capability for metallic surface protection constitutes a priority concern for many key industrial applications. While current technologies largely rely on hazardous chromate-based corrosion inhibitors, this work proposes a simple polymer-based layer-by-layer (LBL) architecture, implemented using easy and fast fabrication techniques. Moreover, this smart coating architecture relies on three environmentally friendly polymers namely polyethylenimine (PEI), polystyrenesulfonate (PSS) and 8-hydroxyquinoline (8HQ) respectively serving as poly-cation, poly-anion and as corrosion inhibitor. Here, this protective coating is deposited and tested on the widely-used Aluminium 2024 alloy to achieve long term protection against corrosion. When structural damages to the coating occur, the inhibitor agents are released to passivate the surface. Raman micro-spectroscopy measurements confirm this effective self-healing capability. This chromate-free coating shows great promises for multiple aerospace, construction and automotive applications.

We report significantly improved silicon nanowire/TiO 2 n + –n heterojunction solar cells prepared by sol–gel synthesis of TiO 2 thin film atop vertically aligned silicon nanowire arrays obtained by facile metal-assisted wet electroless chemical etching of a bulk highly doped n-type silicon wafer. As we show here, chemical treatment of the nanowire arrays prior to depositing the sol–gel precursor has dramatic consequences on the device performance. While hydrofluoric treatment to remove the native oxide already improves significantly the device performances, hydrobromic (HBr) treatment consistently yields by far the best device performances with power conversion efficiencies ranging between 4.2 and 6.2% with fill factors up to 60% under AM 1.5G illumination. In addition to yield high-quality and easy to produce solar cell devices, these findings regarding the surface treatment of silicon nanowires with HBr suggest that HBr could contribute to the enhancement of the device performance not only for solar cells but also for other optoelectronics devices based on semiconductor nanostructures.

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