Month: August 2023

Enlarge / RoboMapper in action. (credit: Aram Amassian)

Earlier this year, two-layer solar cells broke records with 33 percent efficiency. The cells are made of a combination of silicon and a material called a perovskite. However, these tandem solar cells are still far from the theoretical limit of around 45 percent efficiency, and they degrade quickly under sun exposure, making their usefulness limited.

The process of improving tandem solar cells involves the search for the perfect materials to layer on top of each other, with each capturing some of the sunlight the other is missing. One potential material for this is perovskites, which are defined by their peculiar rhombus-in-a-cube crystal structure. This structure can be adopted by many chemicals in a variety of proportions. To make a good candidate for tandem solar cells, the combination of chemicals needs to have the right bandgap—the property responsible for absorbing the right part of the sun’s spectrum—be stable at normal temperatures, and, most challengingly, not degrade under illumination.

The number of possible perovskite materials is vast, and predicting the properties that a given chemical composition will have is very difficult. Trying all the possibilities out in the lab is prohibitively costly and time-consuming. To accelerate the search for the ideal perovskite, researchers at North Carolina State University decided to enlist the help of robots.

Enlarge / A Cybertruck prototype, seen in 2022. (credit: Nic Coury/Bloomberg via Getty Images)

Elon Musk is not impressed with the build quality of Tesla's new Cybertruck. On Wednesday, the Tesla CEO told followers on social media that he "just drove the production candidate Cybertruck at Tesla Giga Texas," as the angular pickup slowly moves from concept to something real people might be able to drive. But workers at the Tesla factory may be in for sleepless nights in the coming weeks and months, judging by a company-wide email first seen by the Cybertruck Owner's Club.

"Due to the nature of Cybertruck, which is made of bright metal with mostly straight edges, any dimensional variation shows up like a sore thumb," Musk wrote in the email. Indeed, every image we've seen of the Cybertruck thus far—including those posted by Musk to his social media account yesterday—shows shockingly inconsistent build quality, particularly at the front of the vehicle where multiple stainless steel panels meet at angles that remind some of a deli slicer.

(credit: Twitter)

"All parts for this vehicle, whether internal or from suppliers, need to be designed and built to sub 10 micron accuracy. That means all part dimensions need to be to the third decimal place in millimeters and tolerances need to be specified in single digit microns. If Lego and soda cans, which are very low cost, can do this, so can we," Musk wrote, referring to products that are the result of decades of constant manufacturing improvement.

Enlarge / The black and golden bumblebee, Bombus auricomus, is typically found in grasslands in the Great Plains and eastern states. (credit: alle12 via Getty)

When ecologist Rachael Winfree first began studying bees 25 years ago, she happened upon a surprise: a species of plasterer bee in the New Jersey Pine Barrens, not seen in 50 years and suspected to have gone extinct. But when she called state wildlife officials to report the discovery, she was told they weren’t interested — they didn’t have the resources to monitor bees and other insects.

This is a familiar scenario to scientists who study native bees. These insects are facing multiple threats, and though official monitoring has improved, their declines have not been well documented. At the same time, a growing body of research is revealing just how crucial native bees are as pollinators for many plants. “They both pollinate our natural systems and — what people don’t realize — they are also really important for many of our agricultural crops,” says Scott Black, executive director of the Xerces Society, a nonprofit focused on invertebrate conservation.

Domestic honeybees are pretty much synonymous with pollination in the public’s mind, particularly when it comes to crops, and the plight of wild bees has largely been overshadowed by concern about threats to the domestic variety. Many people don’t know the difference between wild and domestic bees, further obscuring both the troubles faced by many wild species and their value, says Hollis Woodard, an entomologist at the University of California, Riverside.