In case you missed it (ICYMI), here are some of the stories that made headlines in the world of cleanrooms and nanotechnology in the past week.
A Japanese company has developed a nano-coating of molybdenum that prevents scratches on vinyl music records. The coating can also prevent the records from developing mold and static. The technique is often employed in the semiconductor industry, and now the material – thanks to its ability to resolve vinyl’s poor heat conductivity – could be used to prevent records from warping as well.
A team has built the first quantum cascade laser on silicon. The findings may have applications that span from chemical bond spectroscopy and gas sensing, to astronomy and free-space communications. Integrating lasers directly on silicon chips is challenging, but it is much more efficient and compact than coupling external laser light to the chips. The indirect bandgap of silicon makes it difficult to build a laser out of silicon, but diode lasers can be built with III-V materials such as InP or GaAs. By directly bonding an III-V layer on top of the silicon wafer and then using the III-V layers to generate gain for the laser, this same group has integrated a multiple quantum well laser on silicon that operates at 2 µm. Limitations in diode lasers prevent going to longer wavelengths where there are many more applications, so the group turned their attention to using quantum cascade lasers instead.
Finally, researchers at Linköping University and the Chinese Academy of Sciences are working to avoid costly and unstable fullerenes, thereby making polymer solar cells cheaper and more reliable. Polymer solar cells have come up as a cheap alternative to silicon solar cells. In order to obtain high efficiency, fullerenes are usually required in polymer solar cells to separate charge carriers. However, fullerenes are unstable under illumination, and form large crystals at high temperatures. Now, chemists have set a new world record for fullerene-free polymer solar cells by developing a unique combination of a polymer called PBDB-T and a small molecule called ITIC. With this combination, the sun’s energy is converted with an efficiency of 11 percent, a value that strikes most solar cells with fullerenes, and all without fullerenes.
