Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Pushing the boundaries of colloidal quantum dots by making their sizes equal: Scientists demonstrate the relationship between optoelectronic performance and size uniformity in perovskite colloidal quantum dots

Younghoon kim, Ph.D. (Left) and Prof. Jongmin Choi(Right), DGIST.

CREDIT
DGIST
Younghoon kim, Ph.D. (Left) and Prof. Jongmin Choi(Right), DGIST. CREDIT DGIST

Abstract:
Quantum dots (QDs) are semiconductor particles only a few nanometers across that, thanks to their small size, exhibit peculiar optical and electronic properties due to quantum mechanics. With existing and foreseen applications in screens, lighting, lasers, and energy harvesting, research in quantum dots has been steadily progressing. In particular, colloidal QDs (CQDs) have been in the nanotechnology spotlight for over a decade.

Pushing the boundaries of colloidal quantum dots by making their sizes equal: Scientists demonstrate the relationship between optoelectronic performance and size uniformity in perovskite colloidal quantum dots

Daegu, Republic of Korea | Posted on June 25th, 2021

CQDs are semiconductor nanocrystals that can be produced easily from solution-based processes, which make them suitable for mass production. However, for CQD-based devices to operate at their best, the quantum dots should be monodisperse--that is, they should all have the same size. If their sizes are not equal (polydisperse), the energetic disorder within the optoelectronic device increases, which in turn hinders its performance. While some strategies exist to combat polydispersity in CQDs, the problem is trickier to avoid in perovskite-based CQDs (Pe-CQDs), which require a purification step with an antisolvent. This step invariably leads to nanoparticle agglomeration, and ultimately, large variations in size between quantum dots.

Although producing well-purified monodisperse Pe-CQDs might be necessary to produce highly efficient solar cells, no one has carefully explored the relationship between polydispersity and photovoltaic (conversion) performance. To fill in this knowledge gap, Dr Younghoon Kim and Assistant Professor Jongmin Choi from Daegu Gyeongbuk Institute of Science and Technology, Korea, recently led a team of scientists in a study that published in ACS Energy Letters. The researchers used a technique called gel permeation chromatography to 'filter' and group nanoparticles based on their size, as confirmed by several measurements of their optical properties as well as transmission electron microscopy. With this approach, they managed to obtain suspensions of Pe-CQDs with different degrees of polydispersity.

Afterwards, they used these suspensions to fabricate solar cells and demonstrate the link between polydispersity and performance. As expected, the monodisperse suspension resulted in a better solar cell thanks to its homogeneous energy landscape, which led to higher light absorption within the optimal frequency band. "With the monodisperse Pe-CQDs, our solar cells reached a power conversion efficiency of 15.3% and an open-circuit voltage of 1.27 V. These values are the highest ever reported for Pe-CQDs based on CsPbI3, the perovskite we used," highlights Dr Kim.

Overall, this study is a steppingstone in the field of solar cells based on Pe-CQDs, which still need to outperform their silicon-based counterparts to warrant commercialization. "Research on Pe-CQD solar cells began about four years ago, so further studies are needed to improve device performance and stability. Still, our approach for minimizing energetic disorder using monodisperse Pe-CQDs paves the way to further develop their potential in optoelectronic applications," concludes Dr Choi. Let us hope they eventually manage to join up all the (quantum) dots!

About the authors

Younghoon Kim received his Ph.D. degree from the Department of Chemical and Biological Engineering in Korea University in 2014. He worked as a postdoctoral researcher at the Department of Chemical and Biological Engineering in Korea University (2014-2015) and at the Department of Electrical and Computer Engineering in the University of Toronto, Canada (2015-2017). He is currently a senior researcher at the Division of Energy Technology, DGIST (2017~present). Jongmin Choi is an Assistant Professor in the Department of Energy Science & Engineering at DGIST. He received his B.S. and Ph.D. degrees from the Department of Chemical Engineering in POSTECH in 2010 and 2016, respectively. After that, he worked as a postdoctoral researcher at the Department of Electrical and Computer Engineering in the University of Toronto, Canada (2016-2018).

####

About Daegu Gyeongbuk Institute of Science and Technology (DGIST)
Daegu Gyeongbuk Institute of Science and Technology (DGIST) is a well-known and respected research institute located in Daegu, Republic of Korea. Established in 2004 by the Korean Government, the main aim of DGIST is to promote national science and technology, as well as to boost the local economy. With a vision of "Changing the world through convergence", DGIST has undertaken a wide range of research in various fields of science and technology. DGIST has embraced a multidisciplinary approach to research and undertaken intensive studies in some of today's most vital fields. DGIST also has state-of-the-art-infrastructure to enable cutting-edge research in materials science, robotics, cognitive sciences, and communication engineering.

For more information, please click here

Contacts:
Kwanghoon Choi

82-537-851-133

Copyright © Daegu Gyeongbuk Institute of Science and Technology (DGIST)

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Reference

Related News Press

News and information

Engineering piezoelectricity and strain sensitivity in CdS to promote piezocatalytic hydrogen evolution May 13th, 2022

New nanomechanical oscillators with record-low loss May 13th, 2022

Small microring array enables large complex-valued matrix multiplication May 13th, 2022

Study finds nanomedicine targeting lymph nodes key to triple negative breast cancer treatment: In mice, nanomedicine can remodel the immune microenvironment in lymph node and tumor tissue for long-term remission and lung tumor elimination in this form of metastasized breast cance May 13th, 2022

Display technology/LEDs/SS Lighting/OLEDs

A solution to perovskite solar cell scalability problems April 22nd, 2022

Graphene-hBN breakthrough to spur new LEDs, quantum computing: Study uncovers first method for producing high-quality, wafer-scale, single-layer hexagonal boron nitride April 15th, 2022

Graphene crystals grow better under copper cover April 1st, 2022

Inorganic borophene liquid crystals: A superior new material for optoelectronic devices February 25th, 2022

Perovskites

Quantum ‘shock absorbers’ allow perovskite to exhibit superfluorescence at room temperature April 1st, 2022

“Workhorse” of photovoltaics combined with perovskite in tandem for the first time February 25th, 2022

Photon recycling – The key to high-efficiency perovskite solar cells January 14th, 2022

Possible Futures

Engineering piezoelectricity and strain sensitivity in CdS to promote piezocatalytic hydrogen evolution May 13th, 2022

New nanomechanical oscillators with record-low loss May 13th, 2022

Small microring array enables large complex-valued matrix multiplication May 13th, 2022

Study finds nanomedicine targeting lymph nodes key to triple negative breast cancer treatment: In mice, nanomedicine can remodel the immune microenvironment in lymph node and tumor tissue for long-term remission and lung tumor elimination in this form of metastasized breast cance May 13th, 2022

Discoveries

Going gentle on mechanical quantum systems: New experimental work establishes how quantum properties of mechanical quantum systems can be measured without destroying the quantum state May 13th, 2022

New nanomechanical oscillators with record-low loss May 13th, 2022

Small microring array enables large complex-valued matrix multiplication May 13th, 2022

Study finds nanomedicine targeting lymph nodes key to triple negative breast cancer treatment: In mice, nanomedicine can remodel the immune microenvironment in lymph node and tumor tissue for long-term remission and lung tumor elimination in this form of metastasized breast cance May 13th, 2022

Announcements

Engineering piezoelectricity and strain sensitivity in CdS to promote piezocatalytic hydrogen evolution May 13th, 2022

New nanomechanical oscillators with record-low loss May 13th, 2022

Small microring array enables large complex-valued matrix multiplication May 13th, 2022

Study finds nanomedicine targeting lymph nodes key to triple negative breast cancer treatment: In mice, nanomedicine can remodel the immune microenvironment in lymph node and tumor tissue for long-term remission and lung tumor elimination in this form of metastasized breast cance May 13th, 2022

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Lightening up the nanoscale long-wavelength optoelectronics May 13th, 2022

On-Chip Photodetection: Two-dimensional material heterojunctions hetero-integration May 13th, 2022

Development of high-durability single-atomic catalyst using industrial humidifier: Identification of the operating mechanism of cobalt-based single-atomic catalyst and development of a mass production process. Utilization for catalyst development in various fields including fuel May 13th, 2022

Engineering piezoelectricity and strain sensitivity in CdS to promote piezocatalytic hydrogen evolution May 13th, 2022

Energy

Development of high-durability single-atomic catalyst using industrial humidifier: Identification of the operating mechanism of cobalt-based single-atomic catalyst and development of a mass production process. Utilization for catalyst development in various fields including fuel May 13th, 2022

Engineering piezoelectricity and strain sensitivity in CdS to promote piezocatalytic hydrogen evolution May 13th, 2022

Faster, more efficient nanodevice to filter proton and alkaline metal ions: Monash University researchers have developed a faster, more efficient nanodevice to filter proton and alkaline metal ions which will help design next-generation membranes for clean energy technology, conv April 8th, 2022

USTC found a pathway to high-quality ZnSe quantum wires April 8th, 2022

Quantum Dots/Rods

Development of a single-process platform for the manufacture of graphene quantum dots: Precisely controls the bonding configuration of heteroatoms in graphene quantum dots through simple chemical processes. Practical application and commercialization in various fields is expected December 3rd, 2021

New substance classes for nanomaterials: Nano spheres and diamond slivers made of silicon and germanium: Potential applications as nano semiconductor materials September 10th, 2021

‘Missing jigsaw piece’: engineers make critical advance in quantum computer design August 20th, 2021

Theory describes quantum phenomenon in nanomaterials: Osaka City University scientists have developed mathematical formulas to describe the current and fluctuations of strongly correlated electrons in quantum dots. Their theoretical predictions could soon be tested experimentally December 25th, 2020

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project