Category Archives: RMIT

Exploring small-sized nanoflakes

29 August 2017:

Size-dependent structural and electronic properties of MoSmonolayer nanoflakes, of sizes up to 2nm, have been investigated by CNBP researchers using density-functional theory (DFT). The paper, published in Scientific Reports is accessible online.

Journal: Scientific Reports.

Publication title: A study of size-dependent properties of MoSmonolayer nanoflakes using density-functional theory.

Authors: M. Javaid (pictured), Daniel W. Drumm, Salvy P. Russo & Andrew D. Greentree.

Abstract: Novel physical phenomena emerge in ultra-small sized nanomaterials. We study the limiting small-size-dependent properties of MoS2 monolayer rhombic nanoflakes using density-functional theory on structures of size up to Mo35S70 (1.74 nm). We investigate the structural and electronic properties as functions of the lateral size of the nanoflakes, finding zigzag is the most stable edge configuration, and that increasing size is accompanied by greater stability. We also investigate passivation of the structures to explore realistic settings, finding increased HOMO-LUMO gaps and energetic stability. Understanding the size-dependent properties will inform efforts to engineer electronic structures at the nano-scale.

Nano-diamond arrays on glass

23 August 2017:

Researchers from CNBP’s RMIT University node (lead author Ashleigh Heffernan), have published a paper demonstrating a directed self-assembly method to position nanodiamonds on glass. The method, allowing for the statistical quantification of fluorescent nanoparticles provides a step towards fabrication of hybrid photonic devices for applications from quantum cryptography to sensing.

The paper is accessible online.

Journal: Scientific Reports.

Publication title: Nanodiamond arrays on glass for quantification and fluorescence characterisation.

Authors: Ashleigh H. Heffernan, Andrew D. Greentree & Brant C. Gibson.

Abstract: Quantifying the variation in emission properties of fluorescent nanodiamonds is important for developing their wide-ranging applicability. Directed self-assembly techniques show promise for positioning nanodiamonds precisely enabling such quantification. Here we show an approach for depositing nanodiamonds in pre-determined arrays which are used to gather statistical information about fluorescent lifetimes. The arrays were created via a layer of photoresist patterned with grids of apertures using electron beam lithography and then drop-cast with nanodiamonds. Electron microscopy revealed a 90% average deposition yield across 3,376 populated array sites, with an average of 20 nanodiamonds per site. Confocal microscopy, optimised for nitrogen vacancy fluorescence collection, revealed a broad distribution of fluorescent lifetimes in agreement with literature. This method for statistically quantifying fluorescent nanoparticles provides a step towards fabrication of hybrid photonic devices for applications from quantum cryptography to sensing.

Low-power nonlinear photonic effects

15 August 2017:

Dr Ivan Maksymov from CNBP’s RMIT University node, visited the Department of Physics and Astronomy at Macquarie University Aug 15, 2017 and gave a well attended seminar.

The talk centred on the theory  of low-power nonlinear photonic effects and was formally titled, “Nonlinear optics with low-power light: Transduction of acoustic nonlinearities into the optical domain.”

Girls in Physics

15 August 2017:

Emma Wilson, CNBP PhD student has participated in a ‘Girls in Physics’ outreach program run by the Vicphysics Teachers’ Network in Melbourne, August 15, 2017.

The program, a breakfast event whereby female scientists working in physics or related areas, are teamed up with a table of Year 11/12 female students, is an opportunity to encourage young women to take up further studies in STEMM related subjects after high school.

“This year the main speaker presenting was Katie Mack, an Astrophysicist,” says Emma.

“The aim of the breakfast is to inspire young women and to have people such as myself on hand to answer any questions the students might have regarding a career as a scientist.”

CNBP attracts the crowds at RMIT Open Day

13 August 2017:

Over 400 interested members of the public, including prospective students,  dropped by the CNBP laboratories as a part of RMIT University’s annual Open Day event, Sunday 13th August, 2017.

The Centre had two optics laboratories open and both were fully staffed by researchers eager to share their knowledge and enthusiasm for science.

In the first laboratory, an Olympus wide field microscope was on display with a live-cell incubation chamber and a daphnia (water flea), with brightfield and fluorescence videos.

In the other, a cryogenic confocal microscope was on show, which is able to look at the optical properties of nanomaterials, down to temperatures of 4K (which is -269 deg C).

According to CNBP node leader at RMIT, A/Prof Brant Gibson, the day was a great success.

“We saw a large, interested and engaged crowd who really wanted to find out more about our research and activity, and were curious as to how nanoscale biophotonics was going to impact society over coming years.”

There was also a large number of prospective students who visited and talked with CNBP team members. They had a wonderfully diverse range of interests ranging across the physics, chemistry, biology, IT and engineering disciplines.”

“It was fantastic to see the next generation of excited young scientist!”

The palette of the mind

12 July 2017:

Around fifty high performing Year 10 to Year 12 students from Australia and New Zealand came to RMIT on the 11th of July to listen to CNBP Chief Investigator Prof Andy Greentree present  a talk titled “Colour: the palette of the mind.”

The talk was a part of the Youth ANZAAS visit to RMIT University. Youth ANZAAS 2017 is organised by the Australian and New Zealand Association for the Advancement of Science and the Royal Society of New Zealand. It is is an annual residential international forum for science students still at school.

An abstract of Prof Greentree’s talk follows:

Colour is a complicated phenomenon! For most of us, most of the information we receive about the world comes from light, and that light is encoded by colour. This talk will explore colour. From the physics of light, to how we detect colour information, to the psychophysics of how our brain understands those signals to make sense of the world.

RMIT School of Science Research Day

10 July 2017:

The RMIT School of Science Research Day was held on July 10th, with several members of the RMIT Node presenting CNBP research.

Postgraduate students Daniel Stavrevski, Marco Capelli and Josef Worboys participated in the 3 Minute Thesis competition: Josef Worboys was awarded the winning prize  for his work related to ‘quantum correlations’, and will go on to the University level competition.

The day’s program was concluded with a poster session including posters from CNBP’s Philipp Reineck, Emma Wilson, Nafisa Zohora, Marco Capelli and Ashleigh Heffernan.

Want a better camera? Just copy bees!

4 July 2017:

Check out the latest buzz about bees and their extra light-sensing eyes! CNBP CI Prof Andy Greentree is coauthor on a new paper in PNAS, which identifies how the eyes and brains of honeybees work together, to process colour information.

“If we can design technology to mimic the way bees do this, we’ll be able to create better cameras and image-processing systems for drones and robots,” say the researchers in an article on the science news channel ‘The Conversation‘.

 

Enhancement of the NV quantum yield

3 July 2017:

Researchers from CNBP’s RMIT University node (lead author CNBP PhD student Marco Capelli pictured), have had a paper published in the journal ‘Nanoscale’.

The researchers report an enhancement of the nitrogen-vacancy (NV) quantum yield by up to 7% in bulk diamond caused by an external magnetic field.

The paper is accessible online.

Journal: Nanoscale.

Publication title: Magnetic field-induced enhancement of the nitrogen-vacancy fluorescence quantum yield .

Authors: M. Capelli, P. Reineck, D. W. M. Lau, A. Orth, J. Jeske, M. W. Doherty, T. Ohshima, A. D. Greentree and B. C. Gibson.

Abstract: The nitrogen-vacancy (NV) centre in diamond is a unique optical defect that is used in many applications today and methods to enhance its fluorescence brightness are highly sought after. We observed experimentally an enhancement of the NV quantum yield by up to 7% in bulk diamond caused by an external magnetic field relative to the field-free case. This observation is rationalised phenomenologically in terms of a magnetic field dependence of the NV excited state triplet-to-singlet transition rate. The theoretical model is in good qualitative agreement with the experimental results at low excitation intensities. Our results significantly contribute to our fundamental understanding of the photophysical properties of the NV defect in diamond.

Rethinking food and nutrition science

1 June 2017:

CNBP Research Fellow Dr Philipp Reineck has been selected as a delegate for the ‘Theo Murphy High Flyers Think Tank’, a national group established by The Australian Academy of Science.

The Think Tank will bring together early and mid-career researchers exploring nutrition science in an interdisciplinary fashion.

Findings will contribute to the development of a long term strategic planning process for nutrition research in Australia.

Further information on the Think Tank is available online.