Category Chemistry/Nanotechnology

This map shows the location of seawater samples taken by scientists and citizen scientists that were analyzed at the Woods Hole Oceanographic Institution for radioactive cesium as part of Our Radioactive Ocean. Cesium-137 is found throughout the Pacific Ocean and was detectable in all samples collected, while cesium-134 (yellow/orange dots), an indicator of contamination from Fukushima, has been observed offshore and in select coastal areas. Credit: Figure by Jessica Drysdale, Woods Hole Oceanographic Institution

Scientists monitoring the spread of radiation in the ocean from the Fukushima nuclear accident report finding an increased number of contaminated sites off the US West Coast, along with the highest detection level to date, from a sample collected about 1,600 miles west of SF...

This piece of power paper can store 1F. Credit: Photo Thor Balkhed

Power paper is a new material with outstanding ability to store energy. It consists of nanocellulose and a conductive polymer. 1 sheet, 15 cm in diameter and a few tenths of a mm thick can store as much as 1F, which is similar to the supercapacitors currently on the market. The material can be recharged hundreds of times and each charge only takes a few seconds.

It’s a dream product in a world where the increased use of renewable energy requires new methods for energy storage — from summer to winter, from a windy day to a calm one, from a sunny day to one with heavy cloud cover. “Thin films that function as capacitors have existed for some time. What we have done is to produce the material in 3D...

A typical solar cell, at max, converts <33% of light into electricity, so researchers have been working to find ways to surpass this limit. In the past, scientists have put an extra photon upconversion filter before or after the cell to catch the low energy, unused light and convert it into usable, high-energy light. But, FSU Assistant Prof Hanson wanted to integrate this process directly into the cell.

The researchers did this by using self-assembly. Through a soaking procedure, they assembled 2 molecules, an acceptor and sensitizer, on a surface which work in concert to perform photon upconverion, ie via triplet–triplet annihilation (TTA-UC) combining 2 low energy, green photons to generate a higher energy, blue photon, which can then be used to generate electricity...

The material, technically known as hexagonal boron nitride, features better transparency than its sister, graphene, is chemically inert, or non-reactive, and atomically smooth. It also features high mechanical strength and thermal conductivity. Unlike graphene, however, it is an insulator instead of a conductor of electricity, making it useful as a substrate and the foundation for the electronics in cell phones, laptops, tablets and many other devices.

Growth and transfer of 2-D material such as hexagonal boron nitride and graphene was performed by a team that included Yijing Stehle of Oak Ridge National Laboratory. Credit: ORNL

“Imagine batteries, capacitors, solar cells, video screens and fuel cells as thin as a piece of paper,” said ORNL’s Yijing Stehle...