A new way to make sheets of graphene would boost graphite consumption

first_imgGraphene’s promise as a material for new kinds of electronic devices, among other uses, has led researchers around the world to study the material in search of new applications. But one of the biggest limitations to wider use of the strong, lightweight, highly conductive material has been the hurdle of fabrication on an industrial scale. Initial work with the carbon material, which forms an atomic-scale mesh and is just a single atom thick, has relied on the use of tiny flakes, typically obtained by quickly removing a piece of sticky tape from a block of graphite — a low-tech system that does not lend itself to manufacturing. Since then, focus has shifted to making graphene films on metal foil, but researchers have faced difficulties in transferring the graphene from the foil to useful substrates.Now researchers at MIT and the University of Michigan have come up with a way of producing graphene, in a process that lends itself to scaling up, by making graphene directly on materials such as large sheets of glass. The process is described, in a paper published last week in the journal Scientific Reports, by a team of nine researchers led by A. John Hart of MIT. Lead authors of the paper are Dan McNerny, a former Michigan postdoc, and Viswanath Balakrishnan, a former MIT postdoc who is now at the Indian Institute of Technology.Currently, most methods of making graphene first grow the material on a film of metal, such as nickel or copper, says Hart, the Mitsui Career Development Associate Professor of Mechanical Engineering. “To make it useful, you have to get it off the metal and onto a substrate, such as a silicon wafer or a polymer sheet, or something larger like a sheet of glass,” he says. “But the process of transferring it has become much more frustrating than the process of growing the graphene itself, and can damage and contaminate the graphene.”The new work, Hart says, still uses a metal film as the template — but instead of making graphene only on top of the metal film, it makes graphene on both the film’s top and bottom. The substrate in this case is silicon dioxide, a form of glass, with a film of nickel on top of it.Using chemical vapour deposition (CVD) to deposit a graphene layer on top of the nickel film, Hart says, yields “not only graphene on top [of the nickel layer], but also on the bottom.” The nickel film can then be peeled away, leaving just the graphene on top of the nonmetallic substrate.This way, there’s no need for a separate process to attach the graphene to the intended substrate — whether it’s a large plate of glass for a display screen, or a thin, flexible material that could be used as the basis for a lightweight, portable solar cell, for example. “You do the CVD on the substrate, and, using our method, the graphene stays behind on the substrate,” Hart says.In addition to the researchers at Michigan, where Hart previously taught, the work was done in collaboration with a large glass manufacturer, Guardian Industries. “To meet the manufacturing needs, it must be very scalable,” Hart says. The company currently uses a float process, where glass moves along at a speed of several metres per minute in facilities that produce hundreds of tonnes of glass every day. “We were inspired by the need to develop a scalable manufacturing process that could produce graphene directly on a glass substrate,” Hart says.The work is still in an early stage; Hart cautions that “we still need to improve the uniformity and the quality of the graphene to make it useful.” But the potential is great, he suggests: “The ability to produce graphene directly on nonmetal substrates could be used for large-format displays and touch screens, and for ‘smart’ windows that have integrated devices like heaters and sensors.”Hart adds that the approach could also be used for small-scale applications, such as integrated circuits on silicon wafers, if graphene can be synthesized at lower temperatures than were used in the present study.“This new process is based on an understanding of graphene growth in concert with the mechanics of the nickel film,” he says. “We’ve shown this mechanism can work. Now it’s a matter of improving the attributes needed to produce a high-performance graphene coating.”Christos Dimitrakopoulos, a professor of chemical engineering at the University of Massachusetts at Amherst who was not involved in this work, says, “This is a very significant piece of work for very large-area applications of graphene on insulating substrates.” Compared to other methods, such as the use of a silicon carbide (SiC) substrate to grow graphene, he says, “The fact that the lateral size of graphene in the Hart group’s approach is limited only by the size of the [CVD] reactor, instead of the size of the SiC wafer, is a major advantage.”“This is a high-quality and carefully executed work,” Dimitrakopoulos adds.last_img read more

Column Why I wanted to make a movie about isolation in rural

first_imgWHEN I DECIDED to make Pilgrim Hill, for me it was not about winning awards, being visually stylish or trying to be loud and stand out from the crowd with my debut feature film. For me it was about telling the story of my uncle, who is a bachelor farmer living in rural Ireland.Like many people, I have an uncle/aunt who lives alone in rural Ireland, and although the film has very few similarities to my uncle’s life, I always wondered how tough it must be to face life alone. There are a huge number of people living alone across Ireland right now that feel incredibly isolated and lonely. I wanted to explore how they must feel sometimes in their situation whether in rural or urban Ireland.The things we all fearI wanted to know how they felt about their siblings moving on, having families, and how that affected them. I also wanted to explore their loneliness and isolation, and knowing you will be alone for the rest of your life. I wanted to know what it feels like not to leave a child behind to carry on your legacy. I wanted to find out what they sacrificed in their own lives to get to where they are now, so that in some cases their siblings could go on, better themselves and have families.I think deep down these are all things we fear, being alone and isolated and not having anyone to live out our life with. The done ‘thing’ in our world is – you meet someone that you choose to spend the rest of your life with, have kids, and live out your life together until inevitably the light goes off for one. In a long-term relationship, I think we all fear that and what it would be like if your partner was not there any more. But for some people life is not as easy as that – life, health, work, commitments, and sometimes fear – get in the way of people moving on to do those things.In terms of why people find themselves alone, it all comes down to various circumstances, with some even beyond their control. Jimmy, the main character in Pilgrim Hill, is a victim of circumstance. His mother died when he was very young and he found himself at home caring for his father who is seriously ill. Their relationship is very much in tatters also. He’s trapped. Jimmy feels the need to hold onto home and maybe feels responsible for minding his father, even if that has a massive effect on his own personal life. Jimmy had the chance to marry and set up his own life, but felt he could not leave home and had a duty to mind his father.To a farmer, empty fields and sheds are painfulI also wanted to explore how tough it is for farmers right now in Ireland. It’s late April and no cattle are out in the fields. This is a serious issue as farmers are eating into the feed for winter coming, not a mind putting major financial strains on themselves and their families. What farmers fear most is their cattle getting a critical disease, meaning all of them need to be slaughtered so the disease cannot get into the food chain. But for every positive, you have a negative also. Farmers cannot operate their farms for most of a year. Income is down, meaning an impact on their family lives. To a farmer, seeing empty fields and sheds is painful.On our family farm at home, I witnessed at a very young age the impact that has. I was very young, maybe nine or ten. In the height of winter I went down the farm yard one night with my father and a cow had triplets for the first time. It’s a big deal if you come from a farm, a rarity, some even say a miracle. It was beautiful to witness such a thing and the three baby calves come into the world. My mother was watching on the calving monitor above at home from the kitchen.That night we knew our cattle had contracted a disease and the following morning they were taken away to be slaughtered, including the three baby triplet calves. Cows going into the lorry were even calving, calves half hanging out. It was horrible to think that calves were being born in a slaughter lorry knowing that their only bit of life was going to be there until they were killed a few hours later. It was the first time I saw my father get emotional. I will never forget it. The reality is this happens on a daily basis in rural Ireland to farmers.My film gaining recognitionI was incredibly lucky to find an amazing actor in Joe Mullins who just captivates the screen as Jimmy, as well as the supporting cast and my marvellous crew of three. Since the film premiered at the Galway Film Fleadh in 2012, we have travelled across the world with it from the UK, America, Europe and Asia. The film has connected with audiences wherever it has been, and the reason I think so is because loneliness is a universal feeling whether you are in Ireland or Asia.With that, I think the world right now is a very lonely place for a lot of people, whether it is personal loneliness or financial loneliness. We all have felt it, either are feeling it and will undoubtedly feel it in the future when loved ones move on. The past eight months have been much more than we could have ever hoped for. We received tremendous support from the Irish Film Board and Element Distribution who really got supported the film.We don’t talk enough about how we feel in this countryPilgrim Hill is not an easy film to watch, I am the first to admit that. Saying that, I am also unapologetic about that because I wanted to go deep and explore how this must feel for someone in modern Ireland. I broke a lot of rules making this film, but rules are meant to be broken, you just have to choose when and make sure it’s for the right reasons. Jimmy the main characters talks openly about his feelings to the audience, as in narrating his own story. I wanted to have the person you would least expect talking openly about their feelings, a bachelor farmer in rural Ireland. We don’t talk enough about how we feel in this country and that sometimes sadly ends in tragedy.If the film has any impact, then I hope it will motivate people to call in and see their neighbours, aunts, or uncles who live alone. It costs nothing, but it means the world to them to know there is somebody there. Life’s journey is tough, but it’s a tougher journey if you walk it alone.One of the most poignant lines in the film is when Jimmy says “If I was to die and meet the person I could have been. Instead of the person I am now”. I think we all wonder “what if” sometimes.(EPDistribution/YouTube)Gerard Barrett is a 25-year-old writer/director from Listowel in Kerry. He made Pilgrim Hill in late 2011 over seven days after finishing college. He won the IFTA Rising Star Award in 2013 and subsequently signed with Martin Scorsese agent in WME Los Angeles after the film had its North American premiere at the prestigious Telluride Film Festival where he received the Great Expectation Award. The film also won Best New Irish Talent at the Galway Film Fleadh. Pilgrim Hill is in cinemas across Ireland.Interview: Why I set out to explore the dark side of South Dublin cliquey teens>Column: Can Hollywood produce a female lead who’s interesting in her own right?>last_img read more