#chalcogenides

Scientists develop high-performance Hg-based crystal for mid-far infrared birefringence

Mid- and far-infrared birefringent crystals are key functional materials for polarization control, laser technologies, and infrared photonics. However, existing materials generally suffer from limited infrared transparency, an intrinsic trade-off between large birefringence and wide transmission windows, and challenges in optical characterization due to restricted crystal dimensions. Due to their heavy-element composition and unique coordination environments, Hg-based chalcogenides have emerged as promising candidates for achieving the coexistence of strong birefringence and broad infrared transparency. Nevertheless, a systematic understanding of their structural design principles and structure-property relationships has not been achieved.

Encapsulated PbS quantum dots boost solar water splitting without sacrificial agents

A research team affiliated with UNIST has developed stable and efficient chalcogenide-based photoelectrodes, addressing a longstanding challenge of corrosion. This advancement paves the way for the commercial viability of solar-driven water splitting technology—producing hydrogen directly from sunlight without electrical input. Jointly led by Professors Ji-Wook Jang and Sung-Yeon Jang from the School of Energy and Chemical Engineering, the team reported a highly durable, corrosion-resistant metal-encapsulated PbS quantum dot (PbS-QD) solar cell-based photoelectrode that delivers both high photocurrent and long-term operational stability for photoelectrochemical (PEC) water splitting without the need for sacrificial agents. The research is published in the journal Nature Communications.

Physicists eye emerging technology for solar cells in outer space

Solar cells face significant challenges when deployed in outer space, where extremes in the environment decrease the efficiency and longevity they enjoy back on Earth. University of Toledo physicists are taking on these challenges at the Wright Center for Photovoltaics Innovation and Commercialization, in line with a large-scale research project supported by the Air Force Research Laboratory. One recent advancement pertains to an emerging technology that utilizes antimony compounds as light-absorbing semiconductors. A group of UToledo faculty and students recently published a first-of-its-kind assessment exploring the promising characteristics of these antimony chalcogenide-based solar cells for space applications in the journal Solar RRL, which highlighted the work on its front cover.

Advancements in (Ca,Ba)ZrS₃ solar cells using innovative spinel hole transport layers

Solar power has long been a beacon of hope in our pursuit of clean energy. However, the road to sustainable, high-efficiency photovoltaics has been riddled with roadblocks such as toxicity and instability in widely used lead halide perovskites. Could we engineer a solar cell that delivers not just high performance, but also durability, stability and environmental safety? That question led us to (Ca,Ba)ZrS3, a chalcogenide perovskite with immense promise. Unlike its lead-based counterparts, this material boasts strong thermal and chemical stability. More importantly, its bandgap can be finely tuned down to 1.26 eV with less than 2% calcium doping, placing it squarely within the Shockley-Queisser limit for optimal photovoltaic conversion.

'Self-healing' glass: Study shows gamma radiation induces defects that are healed at room temperature

Self-healing glass may sound like a science fiction concept, but new research from the University of Central Florida demonstrates it's much closer to reality. In a new study published in the journal Materials Research Society Bulletin, UCF College of Optics and Photonics (CREOL) Pegasus Professor Kathleen Richardson and colleagues from Clemson University and the Massachusetts Institute of Technology studied the incredible self-healing capabilities of a specialized chalcogenide glass after it was exposed to gamma radiation. Chalcogenide glasses are comprised of chalcogen elements—sulfur, selenium, and tellurium—alloyed with elements like germanium or arsenic to create optical glass materials that may be applied to sensors or infrared lenses.

New material offers more durable, sustainable multi-level non-volatile phase change memory

Scientists have achieved a breakthrough in the development of non-volatile phase change memory—a type of electronic memory that can store data even when the power is turned off—in a material that has never displayed the sort of characteristics that such memory requires. Until now, phase change memory has primarily been developed using chalcogenides, which are a group of materials known to exhibit reversible electrical changes when they transition between their crystalline and amorphous states. But what if there's an even better material out there? In a study published in Advanced Science on September 3, 2023, researchers report a thermally reversible switching of room-temperature electrical resistivity in a layered nickelate, potentially offering better performance and superior sustainability.

Researchers develop thin film as resistance-switching material for next-generation memristive devices

Memristive devices are capable of retaining their internal resistance, thus offering superior performance compared to conventional devices that use integrated circuits. Several materials have been explored for the manufacture of these devices. In recent years, transition metal oxides have gradually become widely popular for this purpose. Due to their increasing application in diverse domains like artificial intelligence systems, memristive devices must now overcome several issues related to data retention, endurance, and a large number of conductance states. Moreover, the individual fabrication of these devices is time-consuming. As a result, several challenges need to be addressed to improve their performance and reliability. In a recent study led by Professor Min Kyu Yang from Sahmyook University, Korea, researchers have developed a silver (Ag)-dispersive chalcogenide thin film for use as a resistance-switching material in memristive devices. Their paper is published in the journal Applied Surface Science.

A Textbook Dirac Semimetal

Researchers have synthesized a chalcogenide compound that has the electronic structure of an ideal Dirac semimetal—which could facilitate the study of this exotic class of materials.

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Dirac semimetals are exotic quantum materials regarded as three-dimensional analogs of graphene: in such semimetals, as in graphene, the electrons behave as fermions with zero mass, leading to unique optical, magnetic, and transport properties. Only a handful of such systems, however, have been uncovered. A challenge for experimentalists lies in the often complicated electronic  band structure of these materials, which makes it hard to disentangle effects due to the zero-mass relativistic electrons from those due to trivial electronic states. Now a team led by David Santos-Cottin of the University of Fribourg in Switzerland has demonstrated that a chalcogenide compound, TlBiSSe, can be synthesized with an extremely clean and tunable band structure that is characteristic of a Dirac semimetal [1]. The result suggests that TlBiSSe might be an ideal material platform for exploring relativistic-electron phenomena in solids, says Santos-Cottin.