Electronics & Semiconductors

A high efficiency LED based on copper–iodide clusters

A team led by Prof. Yao Hongbin from the University of Science and Technology of China (USTC) developed a high efficiency, high brightness warm white light-emitting diode (LED) based on copper-iodide cluster hybrids. Their ...


Sound-powered sensors stand to save millions of batteries

Sensors that monitor infrastructure, such as bridges or buildings, or are used in medical devices, such as prostheses for the deaf, require a constant supply of power. The energy for this usually comes from batteries, which ...

Energy & Green Tech

Stabilizing perovskite solar cells without lead

Solar cells made from perovskite, a material that is able to harvest sunlight and convert it to electricity, hold great potential as a replacement for silicon solar cells.

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Heavy metal (chemistry)

A heavy metal is a member of an ill-defined subset of elements that exhibit metallic properties, which would mainly include the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight, and some on chemical properties or toxicity. The term heavy metal has been called "meaningless and misleading" in an IUPAC technical report due to the contradictory definitions and its lack of a "coherent scientific basis". There is an alternative term toxic metal, for which no consensus of exact definition exists either. As discussed below, depending on context, heavy metal can include elements lighter than carbon and can exclude some of the heaviest metals. Heavy metals occur naturally in the ecosystem with large variations in concentration. Nowadays anthropogenic sources of heavy metals, i.e. pollution, have been introduced to the ecosystem. Waste derived fuels are especially prone to contain heavy metals so they should be a central concern in a consideration of their use.

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