Lifeboat Foundation

Despite the young age of the research field, substantial progress has been made in the study of metal halide perovskite nanocrystals (HPNCs). Just as their thin-film counterparts are used for light absorption in solar cells, they are on the way to revolutionizing research on novel chromophores for light emission applications. Exciting physics arising from their peculiar structural, electronic, and excitonic properties are being discovered with breathtaking speed. Many things we have learned from the study of conventional semiconductor quantum dots (CSQDs) of II–VI (e.g., CdSe), IV–VI (e.g., PbS), and III–V (e.g., InP) compounds have to be thought over, as HPNCs behave differently. This Feature Article compares both families of nanocrystals and then focuses on approaches for substituting toxic heavy metals without sacrificing the unique optical properties as well as on surface coating strategies for enhancing the long-term stability.

• • Top of Page
  • Abstract
  • Introduction
  • Optical Properties of CSQDs and HPNCs
  • Specificities of Cd- and Pb-Containing NCs Favoring Outstanding Optoelectronic Properties
  • General Strategies for Replacing Toxic Heavy Metals in Nanocrystals
  • Conclusions and Perspectives
  • References

In the early 1980s the quest for novel photocatalysts, fueled by the oil crisis in the preceding decade, led to the discovery of semiconductor quantum dots. Pioneering works by Efros, Brus, and Henglein showed both experimentally and theoretically that the reduction of size of semiconductor particles (e.g., CdS) down to the nanometer range induces a significant change in their band gap energy.(1−3) The underlying quantum confinement effect, occurring when the nanocrystal size is (significantly) smaller than twice the exciton Bohr radius of the semiconductor material (Table 1), leads to an increase, scaling with 1/r, of the band gap energy. It also gives rise to the appearance of discrete energy levels at the place of continuous valence and conduction energy bands. In the same period Ekimov as well as Itoh and co-workers observed quantum confinement in small CuCl crystallites embedded in a glass or a NaCl matrix.

The six newly shortlisted initiatives include: a project that would explore how AI can enhance human capabilities; one to hasten clinical availability of cell and gene therapies; a personalized-medicine initiative; two projects that aim to make solar energy more efficient; and a humanities project called the Time Machine, which seeks to develop methods for enabling digital search of historical records in European cities.

AI enhancement and a virtual time machine are included in the shortlist of pitches.

In a paper to be published in the forthcoming issue in NANO, researchers from the National Institute of Technology, India, have synthesized blue-green-orange photoemissive sulfur and nitrogen co-doped graphene quantum dots (SNGQDs) using hydrothermal method. These GQDs showed strong UV-visible photoabsorption and excitation dependent photoemission which have low-cost, eco-friendly solar cell application.

Quantum dots, which have potential uses in medical imaging and solar cells, could be made with help from the polyphenols found in tea leaves.

The most powerful laser beam ever created has been recently fired at Osaka University in Japan, where the Laser for Fast Ignition Experiments (LFEX) has been boosted to produce a beam with a peak power of 2,000 trillion watts—two petawatts—for an incredibly short duration, approximately a trillionth of a second or one picosecond.

Values this large are difficult to grasp, but we can think of it as a billion times more powerful than a typical stadium floodlight or as the overall power of all of the sun’s solar energy that falls on London. Imagine focusing all that solar power onto a surface as wide as a human hair for the duration of a trillionth of a second: that’s essentially the LFEX laser.

LFEX is only one of a series of ultra-high power lasers that are being built across the world, ranging from the gigantic 192-beam National Ignition Facility in California, to the CoReLS laser in South Korea, and the Vulcan laser at the Rutherford Appleton Laboratory outside Oxford, UK, to mention but a few.

Continue reading “This 2,000 trillion watt laser could re-create the Big Bang–and make clean energy” »

A team of researchers from Michigan State University managed to develop a fully transparent solar panels – a breakthrough that could lead to countless applications in architecture, as well as other fields such as mobile electronics or the automotive industry. Previous attempts to create such a device have been made, but results were never satisfying enough, with low efficiency and poor material quality.

Scientists have characterized the quantum behavior of buckminsterfullerene molecules, also known as buckyballs, with the hope of perhaps one day turning them into miniature quantum computers.

Buckyballs are the Nobel Prize-winning molecules that consist of sixty carbon atoms arranged in a closed, soccer ball-shape. Their peculiar structure bestows them with strange observable quantum properties, and has given them uses in solar panels and even medicine. But a team of scientists from JILA, a research institute run by the National Institute of Standards and Technology and the University of Colorado, has made measurements in preparation for exploiting buckyballs’ quantum properties in even stranger ways.

Window blinds that have solar panels. Solargaps is elegant decision that let you generate energy while keeping your home cool.

Beat the heat while generating electricity with solar panel blinds

Continue reading “Window Blinds Double as Solar Panels” »