Cascade amplified upconversion luminescence facilitating narrow band NIR photodetection

November 11, 2020

Narrow-band near infrared (NIR) photodetectors (PDs) capable to simultaneously detect light in multi-spectral bands, e.g., in the NIR I and NIR II regions, are attracting prodigious attention in diverse areas including biological analysis, multicolor bio-imaging/sensing, and encrypted communications. UCNCs, due to their unique two-photons or multi-photons excitation nature as well as their non-toxic characteristics and low preparation cost, have emerged as a superior solution by converting NIR photons into easily detectable visible photons. However, the relatively high pumping threshold to realize detectable upconversion luminescence (UCL), originating from the lower absorption cross section of 4fn-4fn transitions of rare earth (RE) ions and lower luminescent quantum efficiency of UCNCs because of the anti-Stokes nature, poses a fundamental limitation for weak NIR light detection in photoelectric devices.

In a new paper published in Light Science & Applications, a team of scientists, led by Professors Hongwei Song and Wen Xu from State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, China, Dr. Haichun Liu from Department of Theoretical Chemistry and Biology, KTH Royal Institute of Technology, Stockholm, Sweden, Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden and co-workers have explored a novel cascade optical field modulation strategy integrating the superlensing effect of polymeric microlens arrays (MLAs) and the plasmonic effect of gold nanorods (Au NRs) to boost UCL. This cascade modulation strategy was found to readily lead to a UCL enhancement by more than four orders of magnitude. They designed and synthesized multi-wavelength responsive core-shell-shell (CSS) structured UCNCs that emit visible light under excitation of 808, 980, or 1540 nm, and constructed NIR PDs on top. Realizing that each UCNC constitutes an information-rich kinetic system, possessing characteristic responses to optical signals in the temporal and frequency domains of different excitation wavelengths, they exploited the possibility of separating the channels of multi-wavelengths photodetection to implement selective detection. They proved that the modulation frequency response can be used to well distinguish the detected wavelengths. In addition, the UCL kinetics of the UCNCs was also optimized by manipulating the concentrations of lanthanide dopants, whereby short response times of 80-120 ms for the final PDs were achieved. These scientists summarize the operational principle of their NIR PDs:

"We have designed and synthesized NaYF4: Yb3+, Er3+@NaYF4@NaYF4: Yb3+, Nd3+, Tm3+ core-shell-shell (CSS) UCNCs, which could be excited by 808, 980 and 1540 nm light and generate visible emissions. By using a novel cascade optical field modulation strategy through integrating the superlensing effect of MLAs and the plasmonic effect of Au NRs, significant UCL enhancements from the UCNCs have been obtained, in concrete terms by factors of 2.4×104, 2.2×104, and 1.6×104 for 808, 980, and 1540 nm excitation, respectively."

"In comparison, the employment of the LSPR effect can typically enhance UCL by one order of magnitude, while the usage of the superlensing effect can lead to UCL enhancement by two or three orders of magnitude, when using the same routine and easily obtained nano-/micro-structures."

"The PDs were built based on the synthesized CSS UCNCs adopting the cascade optical field modulation strategy for UCL, which have achieved selective detection to three narrow spectral bands in the NIR region. The PDs possess extremely high responsivity of 30.73, 23.15, and 12.20A/W, and detectivity of 5.36×1011, 3.45×1011, and 1.92×1011 Jones for the 808, 980, and 1540 nm light detection, comparable or well beyond those of other types of NIR PDs such as commercial Ge-based ones, along with short response times in the range of 80-100 ms. "

"Importantly, the incident light wavelength can be well distinguished by a proposed novel approach, i.e., examining the response to the excitation modulation frequency. Our work highlights new concepts to conquer the relatively high pumping threshold of UCNCs, enabling to build high-photoresponsivity and -detectivity multi-band responsive and distinguishable photodetectors on top of them, and can also stimulate other applications of upconversion nanotechnology."
-end-


Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, CAS

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.