A new method for quantifying crystal semiconductor efficiency

August 23, 2019

Japanese scientists have found a new way to successfully detect the efficiency of crystal semiconductors. For the first time ever, the team used a specific kind of photoluminescence spectroscopy, a way to detect light, to characterize the semiconductors. The emitted light energy was used as an indicator of the crystal's quality. This method potentially culminates in more efficient light-emitting diodes (LEDs) and solar cells. Additionally, it could usher in several other advances in electronics.

The research, published in APL Materials on July 31, 2019, involves crystals called lead halide perovskites - unique types of materials with structures efficient for solar cell performance. The crystals consist of an organic material interlocked with an inorganic one. Perovskites are semiconductor materials that have many applications. They are more efficient and much easier and cheaper to make than standard commercial solar cells.

Furthermore, these promising crystals could also lead to new electronic displays, sensors and other devices that are activated by light, bringing increased efficiency at a lower cost to manufacturers of optoelectronics that harness light. In addition, these crystals have the potential to harvest solar energy. Most solar cells are made with silicon crystals, a relatively straightforward and effective material to process. However, perovskite-based devices are likely to offer higher conversion efficiencies than silicon.

"For further development of perovskite-based devices, it is essential to quantitatively evaluate the absolute efficiency in high-quality perovskite crystals without assuming any predefined physical model is of particular importance," said corresponding author Kazunobu Kojima, Associate Professor at Tohoku University, Japan. "Our method is new and unique because previous methods have relied on efficiency estimation by model-dependent analyses of photoluminescence."

Understanding photoluminescence is important for designing devices that control, generate or detect light, including solar cells, LEDs and light sensors. So far, these detections have largely relied on theoretical modelling as a way to predict the efficiency of perovskite-based semiconductors. For this research, the authors have implemented a technique they originally proposed in 2016 called Omnidirectional Photoluminescence Spectroscopy or "ODPL spectroscopy." The procedure is a contactless, nondestructive method of probing the electronic structure of the crystals from all directions, enabling them to easily and quickly quantify the crystals' properties.

An important next step is to implement ODPL spectroscopy to investigate different types of perovskite materials. This may lead to better understanding of crystal-based semiconductors as well as more efficient ones. The authors state that their future studies will focus on both increasing crystal efficiency and ensuring that it is unified across all areas of materials.
-end-
This work was partly supported by the Five-Star Alliance, Japan Society for the Promotion of Science KAKENHI (Grant Nos. JP16H06427, JP17H02907, and JP17H04809), and Japan Science and Technology Agency - CREST (Grant No. JPMJCR16N3). Title: Internal quantum efficiency of radiation in a bulk CH3NH3PbBr3 perovskite crystal quantified by using the omnidirectional photoluminescence spectroscopy

Authors: Kazunobu Kojima, Ken-ichiro Ikemura, Kouhei Matsumori, Yasuhiro Yamada, Yoshihiko Kanemitsu, and Shigefusa F. Chichibu

Journal: APL Materials

DOI: 10.1063/1.5110652

Tohoku University

Related Science Articles from Brightsurf:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.

Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.

Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.

Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.

World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.

PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.

Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.

Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.

Read More: Science News and Science Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.