Technology


University team restarts research on molecular electronics, thanks to precise positioner


Researchers at the University of Liverpool are using Physik Instrumente (PI) actuators to hold and precisely manipulate single molecules in their molecular electronics research. Their work is looking at the fundamental principles underlying this potentially powerful technology, and PI’s N-216 NEXLINE series actuators are helping to achieve far more than was previously possible. Molecular electronics promises greater


miniaturisation of devices at reduced cost, since components will be built up from molecules, rather than ‘broken down’ from semiconductor wafers. Yet it’s now 30 years on and the molecular computer is still just a pipe dream, with very slow progress achieved. More recently, research into this


technology has restarted, focusing on how molecules behave at the quantum level and the chemical complexities involved. These findings will feed into product development, exploiting such quantum phenomena to achieve greater performance – better charge transport but using less


power. One aspect of this is studying light emission from 1-2nm devices. The University of Liverpool’s


experimental setup is based on a single molecule positioned between two electrodes – one anchored to keep it from moving, and the other linked to a piezo positioner for small adjustments. The junction can then be fine-tuned to the correct dimensions where the molecule is perfectly extended, rather than stretched or compressed. To collect more photons, the team used the NEXLINE series actuators from PI, for a very precise and stable positioner. The actuator works on the PiezoWalk


principle, offering sub-nanometre precision and great stability; it can hold a position for minutes with no significant drift and very low piezo creep, avoiding problems created by other piezo-based positioners. The result is a stable molecular junction at room temperature held for minutes, rather than seconds. “Collecting light emission for this length of time means we can now record a whole


Experimental single-molecule light emission set-up using a PI N-216 nanopositioner. Inset (A) shows a magnification of the two electrodes. Inset (B) shows an idealised depiction of a single molecule suspended between the two


spectrum, compared to the low counts only at the emission maxima we could achieve before,” said Dr Andrea Vezzoli, a Royal Society Research Fellow from the Department of Chemistry and Stephenson Institute for Renewable Energy at the University of Liverpool.


Research shows MPEG-5 LCEVC improves codec efficiency and encoding speed


Video compression solutions provider V-Nova has conducted a study with Intel and Meta to evaluate the impact of MPEG- 5 Low Complexity Enhancement Video Coding (LCEVC) on the performance of existing codec implementations. Te study determines how LCEVC can improve compression efficiency compared to complexity trade-offs of native SVT-AV1, x264 and x265 for video on demand (VOD) applications. Te team tested over 650,000 encoders,


comprising 140 clips, across eight resolutions, multiple bit rates and 25 different presets, using four different


visual quality metrics – VMAF, PSNR, VMAF_NEG and SSIM. Results showed improvements in compression and computational performance for all tested codecs, as well as AV1 decodability. Using dynamically-optimised convex-hull


methodology in conditions typically used for VOD encoding by streaming and social network services, LCEVC showed marked quality improvements. Also, LCEVC- enhanced videos achieve the same quality levels at ~ 40% reduction in computations when used in conjunction with SVT-AV1. Te combination of LCEVC and SVT-AV1 builds on already notable improvements of


06 February 2023 www.electronicsworld.co.uk


SVT-AV1 and establishes the possibility of widespread and energy-efficient use. In addition, enhancing AV1 with LCEVC


broadens the set of mobile devices capable of playing back full HD AV1 content. Mobile battery life was also extended by up to 50% compared with non-enhanced streams using state-of-the-art AV1 soſtware decoders Dav1d and GAV1. “Tese are the results of an amazing


effort between all parties, to finally provide a set of quantitative results of the benefits of MPEG-5 LCEVC in a very relevant application,” said Guido Meardi, CEO of V-Nova.


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