Two papers have recently been published on Iridium complexes incorporating acetylacetone and C-N based bidentate ligands. One paper is published in Chem Comm, by a European based group, the other is in Advance Materials by a collaboration out of China and Hong Kong.

The european group reports an octahedral compound (termed N966) with three ligands; 2 phenylimidazoles (coordinating to the Ir through a C and a N on the imidazole) and 1 acetylacetone. In solutions of DCM, at room temperature, it displays broad unstructured emission over the spectral range of 440nm – 800nm, centered around 570nm. It exhibits a PLQY (quantum yield) of 1.5% and radiative lifetime of almost 2μs. CV of the compound in DMSO exhibits reversible oxidation and reduction.
Bolink, H., De Angelis, F., Baranoff, E., Klein, C., Fantacci, S., Coronado, E., Sessolo, M., Kalyanasundaram, K., Grätzel, M., & Nazeeruddin, M. (2009). White-light phosphorescence emission from a single molecule: application to OLED Chemical Communications DOI: 10.1039/b908946b

The group in asia report of a polymer white LED (PWLED), created by doping blue light emitting iridium complexes with yellow iridium complexes, incorporating an electron-transporting material as well!

Wu, H., Zhou, G., Zou, J., Ho, C., Wong, W., Yang, W., Peng, J., & Cao, Y. (2009). Efficient Polymer White-Light-Emitting Devices for Solid-State Lighting Advanced Materials DOI: 10.1002/adma.200900638

These two papers illustrate the different approaches to the WOLEY grail :) I prefer the purer approach as I think it will ultimately result in a higher quality of fabricated devices, but I also appreciate that this approach will require a lot of trial and error….which is why I’m glad I’m not doing the research!

abc © interestedinscience.com

ResearchBlogging.org

In the interests of science, humanity, and making an honest-to-god attempt at total political transparency – I ask: what the hell is going on?!?! I’m reading that obama’s administration has decided to devastate the H-cell research field by cutting its budget by $100 million. AAAGGHH! (Being an eternal cynic I’m scared that where america lead the UK may follow…)

I’m british, and as such couldn’t vote in November. Needless to say that Obama received my ‘virtual’ vote. I was happy to hear he was for more funding for stem-cell research and against the war in iraq – these were the notions of a sane and well balanced, academically informed and astute leader. WOOP! The most powerful man in the world is behaving like one.

And now I read in Science (see citation below) that Steven Chu (dept energy sec) doesnt see H-cells as having a viable future.

Not wishing to hamper my attempts at reasoning, but even a four year old watching Top Gear last season can see the enormous step forward being made (or, now at least, hampered)

Or just read the paper below if you can follow the link.

A car has always been a continual mode of transport, by that I mean something that go from A to B, then to C, then to D, E, F, G…. and so on, refilling as it goes. Battery power doesn’t allow for this. Charges can take over night.

Hydrogen Fuel cell technology will get better – but not without funding.

Service, R. (2009). Hydrogen Cars: Fad or the Future? Science, 324 (5932), 1257-1259 DOI: 10.1126/science.324_1257

ResearchBlogging.org

Hello world! Hopefully there will be some people still following this much neglected blog about what interests me in science, but I fear my 8 month sabatical may have lost even the few :(

I have been busy finding my work so time-consuming that I havent really had a chance to look at non-PhD research-related science. This is not to say that I havent found any science interesting-it’s just I havent had a chance to write about it! So, my apologies!

I am going to attempt to start blogging more frequently – but I am widening the scope of the site: I have decided to blog some about my interest in computers, especially programming (semi-sciency ???) as I have found it quite interesting recently, and that is essentially what this site is about for me – things I find interesting!

So….here’s to starting up with the blogging once more….

abc

I love the news recieved by the world at large this week – the LHC at Cern, Switzerland, is up and running, and the world is still here…Phew!

However, the LHC is not fully up and running.

I am not a physicist – I’m barely a chemist – but I know from all things computation/instrumental that everything needs time to warm up.

Does this mean the black hole could still be formed and suck everything towards the Alps when they do finally get round to the first full run???

Well, in the spirit of fun, allow me to point you to this website:

www.hasthelargehardoncolliderdestroyedtheworldyet.com

Enjoy ;)

abc interestedinscience.com © 2008

My apologies to the avid readers (!) of this site by my recent lack of news – holidays/shock reports/presentations/poster design and god-awful lab visitors have rendered me free of any time to write anything here. SO – again, my apologies, and I will try and be better over the coming months. Everything has been completed (apart from imminent poster-talk at conference) so I’m looking forward to my blog-vent when I get back.

abc

OK, very quick post as just about purely B-E-A-utiful technology. Below is the newest prototype OLED screen from Sony, as recently (today) mentioned on GIZMODO.com.

STUNNING. At 0.01inches thick and a still impressive resolution of 960×540, it makes me, quite frankly, sick.

Taken from GIZMODO, the new SONY OLED screen

Read more at GIZMODO.

interestedinscience.com © 2008

Well, it has been rumoured for a while now and its properties as a potential silicon-replacement have been exhalted for several years, but it looks that finally the worlds smallest transistors will be graphene based.

In science yesterday a team at Manchester have reported the development of a transistor made of graphene only 1 atom thick (graphene is a flat molecule – the graphite in your pencil is many sheets of graphene) and 10 atoms long.

This is (pardon the magnitude-based pun) huge news!

Ever since Richard Feynman’s lectures on the potential for miniaturization of circuitry, nanoscience has been one of the (if not in fact THE) fastest growing areas of science. And this latest development is at the very frontier and epitomizes what I’m sure Prof Feynman was hinting at.

The paper can be read in full at the following link (if you have access). If you don’t there is a well written commentary here on the BBC website.

There is also a commentary (Science Perspective doi: 10.1126/science.1156936) on Graphene in the journal science through this link.

The paper from the Manchester group is cited below.

Ponomarenko, L.A., Schedin, F., Katsnelson, M.I., Yang, R., Hill, E.W., Novoselov, K.S., Geim, A.K. (2008). Chaotic Dirac Billiard in Graphene Quantum Dots. Science, 320(5874), 356-358. DOI: 10.1126/science.1154663
ResearchBlogging.org

interestedinscience.com © 2008

I remember posting sometime late last year about the potential for even more memory in your iPod (160Gb just isn’t enough!?!) – Atomic Memory Storage…(01/09/2007) – but here is yet another hint at what the future has in store for us…

Published this week in Science a team at IBM have declared they have a novel way of successfully storing fast and stable memory in something called ‘racetrack’ memory. The idea is that memory is stored on nanowires, and electrons are pushed around the track, moving domains which can be charged one way of another, ultimately as 1 or 0 (binary storage) depending on which way the domain is magnetized.

The journal article is cited below, but the following link should take you to an introductory article in science which explains the science (and controversy it’s causing) with a bit more detail.

http://www.sciencemag.org/cgi/content/full/320/5873/166?rss=1

ResearchBlogging.org
Hayashi, M., Thomas, L., Moriya, R., Rettner, C., Parkin, S.S. (2008). Current-Controlled Magnetic Domain-Wall Nanowire Shift Register. Science, 320(5873), 209-211. DOI: 10.1126/science.1154587

interestedinscience.com © 2008

I missed this last week whilst on holiday, but on 18.03.08 Chem. Comm. published a Chinese group’s work on the development of an Iridium dopant for OLEDs which allows, potentially, 100% conversion of energy into light!

The inclusion of the dopant highlights the importance of heavy metals in (ironically termed??) OLEDs. Fully organic LEDs cannot achieve better than 25% due to the nature of the excited states being formed and the ratio of emissive:non-emissive ‘excitons’ (N.B. this isn’t the best use of the word but allow me some poetic license here please!!). Inclusion of the heavy metal (sometimes platinum, more often iridium) allows conversion of the non-emissive ‘excitons’ to be converted to emissive ones (intersystem crossing – see a jablonski diagram for more info on this!).

Pretty colours available for OLEDs
Totally pointless picture but looks pretty – taken from RSC news site.
The Chinese group use a large highly conjugated ligand which still allows high solubility, and best of all, it was all done serendipitously! The biggest breaks usually are done by luck…
Read the paper for more:

ResearchBlogging.orgTong, B., Mei, Q., Wang, S., Fang, Y., Meng, Y., Wang, B. (2008). Nearly 100% internal phosphorescence efficiency in a polymer light-emitting diode using a new iridium complex phosphor. Journal of Materials Chemistry DOI: 10.1039/b800977e

interestedinscience.com © 2008

Ha ha! At last some certifiable published research/progress on the flat-screen/organic electronics-printing front (sorry for that appauling intro…it’s early).

Japanese scientists have published in PNAS (see citation at bottom – next edition) a method to reliably print flat screen panels using a fancy new inkjet style printer (see also BBC News). The technique allows them to circumvent the problems of todays silicon-based flat panel printing processes which in order to obtain maximum purities and performances have yielded to higher processing temperatures, increased manufacturing costs, and thus a higher price for the consumer – exactly what plastic electronic technology is designed to help combat.

The inkjet printers are able to print dots of 1 micron (a millionth of a meter, 1×10-6m, a thousandth of a millimeter…very small!) on to a flexible organic semiconductor. Current printing techniques are limited in their abilities to replicate the resolutions achieved by silicon-based devices and other lithographic techniques for several reasons – one being surface tension of the inks. This new printing technique allows droplet volumes of less than 1 femtolitre – a millionth that which recent techniques allowed.

All in all…yes! Very happy with this development.
See citation below for full article…

Sekitani, T., Noguchi, Y., Zschieschang, U., Klauk, H., Someya, T. (2008). Organic transistors manufactured using inkjet technology with subfemtoliter accuracy. Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0708340105

ResearchBlogging.org
interestedinscience.com © 2008

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