A novel low-cost aluminum–graphite dual-ion battery is reported. The battery shows a reversible capacity of ≈100 mAh g⁻¹ and a capacity retention of 88% after 200 charge–discharge cycles. A packaged aluminum–graphite battery is estimated to deliver an energy density of ≈150 Wh kg⁻¹ at a power density of ≈1200 W kg⁻¹, which is ≈50% higher than most commercial lithium ion batteries.

Clinical applications of current photodynamic therapy (PDT) agents are often limited by their low singlet oxygen (¹O₂) quantum yields, as well as by photobleaching and poor biocompatibility. Here we present a new PDT agent based on graphene quantum dots (GQDs) that can produce ¹O₂ via a multistate sensitization process, resulting in a quantum yield of ~1.3, the highest reported for PDT agents. The GQDs also exhibit a broad absorption band spanning the UV region and the entire visible region and a strong deep-red emission. Through in vitro and in vivo studies, we demonstrate that GQDs can be used as PDT agents, simultaneously allowing imaging and providing a highly efficient cancer therapy. The present work may lead to a new generation of carbon-based nanomaterial PDT agents with overall performance superior to conventional agents in terms of ¹O₂ quantum yield, water dispersibility, photo- and pH-stability, and biocompatibility.

Small-diameter (1 to 7 nanometers) silicon nanowires (SiNWs) were prepared, and their surfaces were removed of oxide and terminated with hydrogen by a hydrofluoric acid dip. Scanning tunneling microscopy (STM) of these SiNWs, performed both in air and in ultrahigh vacuum, revealed atomically resolved images that can be interpreted as hydrogen-terminated Si (111)-(1 × 1) and Si (001)-(1 × 1) surfaces corresponding to SiH ₃ on Si (111) and SiH ₂ on Si (001), respectively. These hydrogen-terminated SiNW surfaces seem to be more oxidation-resistant than regular silicon wafer surfaces, because atomically resolved STM images of SiNWs were obtained in air after several days' exposure to the ambient environment. Scanning tunneling spectroscopy measurements were performed on the oxide-removed SiNWs and were used to evaluate the electronic energy gaps. The energy gaps were found to increase with decreasing SiNW diameter from 1.1 electron volts for 7 nanometers to 3.5 electron volts for 1.3 nanometers, in agreement with previous theoretical predictions.