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A research team has developed a novel “pulse-shaped” light method to enhance the electrical conductivity of PbS quantum dot solar cells. This new technique, which replaces the lengthy traditional heat treatment process, generates substantial energy at regular intervals, significantly improving efficiency and addressing defects caused by light, heat, and moisture exposure. PbS quantum dots, known for their wide absorption range and low processing costs, are now more viable for commercial use. This advancement is expected to facilitate the broader application of quantum dot technology in optoelectronic devices. Credit: SciTechDaily.com.

A research team headed by Professor Jongmin Choi from the Department of Energy Science and Engineering at Daegu Gyeongbuk Institute of Science and Technology has successfully developed a “PbS quantum dot” capable of quickly improving the electrical conductivity of solar cells. This collaborative effort involved Professor Changyong Lim of the Department of Energy Chemical Engineering at Kyungpook National University, led by President Wonhwa Hong, and Professor Jongchul Lim from the Department of Energy Engineering at Chungnam National University, under the leadership of President Jeongkyoum Kim.

The team identified a method to enhance electrical conductivity through the use of “pulse-shaped” light, which generates substantial energy in a concentrated manner at regular intervals. This method could replace the heat treatment process, which requires a significant amount of time to achieve the same result. This approach is expected to facilitate the production and commercialization of PbS quantum dot solar cells in the future.

The team spent years perfecting an intricate process for manufacturing two-dimensional arrays of atom-sized qubit microchiplets and transferring thousands of them onto a carefully prepared complementary metal-oxide semiconductor (CMOS) chip. This transfer can be performed in a single step.

“We will need a large number of qubits, and great control over them, to really leverage the power of a quantum system and make it useful. We are proposing a brand new architecture and a fabrication technology that can support the scalability requirements of a hardware system for a quantum computer,” says Linsen Li, an and computer science (EECS) graduate student and lead author of a paper on this architecture.

A study from Japan published in the International Journal of Computer Aided Engineering and Technology reveals a way to optimize the composition of functionally graded materials (FGMs). FGMs are advanced composite materials with a gradual variation in composition and properties across their volume, designed to optimize performance under specific loading conditions.

There are three ways to look for evidence of alien technological civilizations. One is to look out for deliberate attempts by them to communicate their existence, for example, through radio broadcasts. Another is to look for evidence of them visiting the solar system. And a third option is to look for signs of large-scale engineering projects in space.

A team of astronomers have taken the third approach by searching through recent astronomical survey data to identify seven candidates for alien megastructures, known as Dyson spheres, “deserving of further analysis.”

This is a detailed study looking for “oddballs” among stars—objects that might be alien megastructures. However, the authors are careful not to make any overblown claims. The seven objects, all located within 1,000 light-years of Earth, are “M-dwarfs”—a class of stars that are smaller and less bright than the sun.

Editor’s note: This story is part of ‘Meet a UChicagoan,’ a regular series focusing on the people who make UChicago a distinct intellectual community. Read about the others here.

When asked to explain the difference between recyclable plastics, Pritzker School of Molecular Engineering graduate student Sam Marsden pulled out a paperclip chain and a length of small strings crudely knotted together.

The paperclip chain represented a highly recyclable plastic like the polyethylene terephthalate, or PET, found in soda bottles and the fibers in clothes. These can be broken down to the molecular level—ie., the individual paperclips—and rebuilt into like-new materials.

While silicon has been the go-to material for sensor applications, could polymer be used as a suitable substitute since silicon has always lacked flexibility to be used in specific applications? This is what a recent grant from the National Science Foundation hopes to address, as Dr. Elsa Reichmanis of Lehigh University was recently awarded $550,000 to investigate how polymers could potentially be used as semiconductors for sensor applications, including Internet of Things, healthcare, and environmental applications.

Illustration of an organic electrochemical transistor that could be developed as a result of this research. (Credit: Illustration by by Ella Marushchenko; Courtesy of Reichmanis Research Group)

“We’ll be creating the polymers that could be the building blocks of future sensors,” said Dr. Reichmanis, who is an Anderson Chair in Chemical Engineering in the Department of Chemical and Biomolecular Engineering at Lehigh University. “The systems we’re looking at have the ability to interact with ions and transport ionic charges, and in the right environment, conduct electronic charges.”