Four pulses of laser light on nanoparticle photocells in a spectroscopy experiment has opened a window on how captured sunlight can be converted into electricity. The work, which potentially could inspire devices with improved efficiency in solar energy conversion, was performed on photocells that used lead-sulfide quantum dots as photoactive semiconductor material.
Among the most revolutionary concepts of modern physics is that the laws of nature are inherently non-local. One striking manifestation of this non-locality was famously predicted by Aharonov and Bohm: a magnetic field confined to the interior of a solenoid can alter the behavior of electrons outside it, shifting the phase of their wave-like interference although they never directly encounter the magnetic field. Originally regarded as a mere curiosity, such "geometric phase shifts" are now known to have dramatic consequences for electron transport in solid-state materials, e.g., allowing unimpeded current flow along the edges of a material that is insulating in the bulk.
Scientists have discovered a way to dramatically increase the selectivity and binding strength of crown ethers by incorporating them within a rigid framework of graphene. Strong, specific electrostatic binding of crown ethers may advance sensors, chemical separations, nuclear-waste cleanup, extraction of metals from ores, purification and recycling of rare-earth elements, water purification, biotechnology, energy production in durable lithium-ion batteries, catalysis, medicine and data storage.