Sunday, July 30, 2017
Researchers have demonstrated how a non-toxic alternative to lead could form the basis of next-generation solar cells (for example: GOAL ZERO NOMAD 7 )
The team of researchers, from the University of Cambridge and the United States, have used theoretical and experimental methods to show how bismuth - the so-called "green element" which sits next to lead on the periodic table, could be used in low-cost solar cells.
Their results, reported in the journal Advanced Materials, suggest that solar cells incorporating bismuth can replicate the properties that enable the exceptional properties of lead-based solar cells, but without the same toxicity concerns.
Later tests by another research group showed that bismuth-based cells can convert light into energy at efficiencies up to 22%, which is comparable to the most advanced solar cells currently on the market.
Most of the solar cells which we see covering fields and rooftops are made from silicon. Although silicon is highly efficient at converting light into energy, it has a very low "defect tolerance", meaning that the silicon needs to have very high levels of purity, making it energy-intensive to produce.
Over the past several years, researchers have been looking for materials which can perform at similar or better levels to silicon, but that don't need such high purity levels, making them cheaper to produce. The most promising group of these new materials are called hybrid lead halide perovskites, which appear to promise a revolution in the field of solar energy.
As well as being cheap and easy to produce, perovskite solar cells have, in the space of a few years, become almost as energy-efficient as silicon. However, despite their enormous potential, perovskite solar cells are also somewhat controversial within the scientific community, since lead is integral to their chemical structure.
Whether the lead contained within perovskite solar cells represents a tangible risk to humans, animals and the environment is being debated, however, some scientists are now searching for non-toxic materials which could replace the lead in perovskite solar cells without negatively affecting performance.
"We wanted to find out why defects don't appear to affect the performance of lead-halide perovskite solar cells as much as they would in other materials," said Dr Robert Hoye of Cambridge's Cavendish Laboratory and Department of Materials Science and Metallurgy, and the paper's lead author. "If we can figure out what's special about them, then perhaps we can replicate their properties using non-toxic materials."
In collaboration with colleagues at MIT, the National Renewable Energy Laboratory and Colorado School of Mines in the US, the Cambridge researchers have shown that bismuth, which sits next to lead in the periodic table, could be a non-toxic alternative to lead for use in next-generation solar cells. Bismuth, known as the "green element", is widely used in cosmetics, personal care products and medicines. Like lead, it is a heavy metal, but it is non-toxic.
For this study, Hoye and his colleagues looked at bismuth oxyiodide, a material which was previously investigated for use in solar cells and water splitting, but was not thought to be suitable because of low efficiencies and because it degraded in liquid electrolytes. The researchers used theoretical and experimental methods to revisit this material for possible use in solid-state solar cells.
They found that bismuth oxyiodide is as tolerant to defects as lead halide perovskites. Bismuth oxyiodide is also stable in air for at least 197 days, which is a significant improvement over some lead halide perovskite compounds. By sandwiching the bismuth oxyiodide light absorber between two oxide electrodes, they were able to demonstrate a record performance, with the device converting 80% of light to electrical charge.
The bismuth-based devices can be made using common industrial techniques, suggesting that they can be produced at scale and at low cost.
"Bismuth oxyiodide has all the right physical property attributes for new, highly efficient light absorbers," said co-author Professor Judith Driscoll, of the Department of Materials Science and Metallurgy. "I first thought of this compound around five years ago, but it took the highly specialised experimental and theoretical skills of a large team for us to prove that this material has real practical potential."
"This work shows that earlier theories about bismuth oxyiodide were not wrong, and these compounds do have the potential to be successful solar cells," said Hoye, who is a Junior Research Fellow at Magdalene College. "We're just scratching the surface of what these compounds can do."
"Previously, the global solar cell research community has been searching for non-toxic materials that replicate the defect tolerance of the perovskites, but without much success in terms of photovoltaic performance," said Dr David Scanlon, a theorist at UCL not involved in this work.
"When I saw this work, my team calculated based on the optical properties that bismuth oxyiodide has a theoretical limit of 22% efficiency, which is comparable to silicon and the best perovskite solar cells. There's a lot more we could get from this material by building off this team's work."
Saturday, April 1, 2017
“Teamwork is an individual skill.” – Avery, 2001
When team is effective, emotions of enjoyment overwhelm us leading to everyone in the team feeling satisfied. As productiveness increases, trust grows stronger and satisfaction enhances success and efficiency. The result is a productive team which easily reaches goals.
The question is how productive can teamwork be in a business setting? The answer can be quite simple: since we are egoistic beings and find content in success, if we commit ourselves to our team to that extent to be egoistic about it, our actions will be oriented toward the team succeeding.
Where lies the success of a team? It lies in an achieved common goal.
Does the same apply in the modern world to distant/virtual working? Of course it does. It has become obvious that the number of virtual businesses, virtual departments and virtual teams is on the increase. Cisco reports in their study from 2009 that virtual teams perform better. What was once an obstacle (such as working in an office), is now overcome (with the help of the internet and cloud platforms). Availability and no space constraints are the new reality. In addition, when talking about success, it is crucial to note that teams perform better when they are composed out of men and women, rather than homogenous groups.
A virtual platform, such as Tally Fox, can guarantee ease and safety of communication, increase in productivity and quality of performance through implementing the following teamwork strategies:
Commitment. There is not a single person in this world who has not learned from everyday experience that if we commit ourselves to something, we are already half way to succeeding. In fact, Canadian Olympic Gold medalist Adam Kreek lists commitment as the thing that determines whether a team will be made or broken. He believes that in order for a team to be effective, team members must let go of their ego, the need to control and in some cases their own ideas which have not been accepted by others.
It is, indeed, difficult to change attitudes, standards, routines and even work ethics. Committing to the team means embracing their attitudes, ideals and routines, growing closer to them and to the common goal.
Tuesday, March 7, 2017
Running a small business sometimes feels like navigating a ship in the middle of a storm in the ocean while you are still building the hull. There are hundreds of items on your mind at any given time and dozens of people vying for your attention. At the same time, you cannot afford to take your eye off the primary responsibility, which to manage and grow this business. Amidst this “chaos” your best bet is to look for solutions that make your life easier by offloading some of the tasks from your plate letting you focus on strategic aspects of the business. Here are some solutions that can do just that.
Perfect your payroll
Back in the bad old days – when the best technology we had was an abacus and some pen and paper – sorting out your payroll was more difficult than astrophysics. Now, however, you barely even need to concern your HR department with payment systems. Top-notch payroll solutions can automate your pay with minimal effort, leaving your HR department to get on with other tasks.
With this tech in place, you’ll save a lot of busywork for your staff – and increase the efficiency of your company.
Sunday, February 26, 2017
Carbon footprint is one of the most talked about topics in the business community lately. Humans have made significant impact to the environment in the last 50 years in the name of industrial progress. For individuals and business owners alike, it behooves to pay attention to the carbon footprint they generate and find ways to reduce it to at least stem the deterioration of earth’s atmosphere, if not reverse the adverse impact from global warming. What can small business owners do to play their part in this effort? Here are 3 simple ways you can help by becoming more energy efficient:
- Educate Your Employees
The first step to improving your energy consumption habits is education. While many of us are getting better at it, there are still times when we are unaware that are actions are having detrimental effects. Perhaps the biggest example of wasted resources in the workplace is failing to power down your computer at the end of the day. A simple post-it-note left as a reminder may prove to solve the problem, though this may turn out to be only a temporary solution. More creative companies have turned to rewarding their employees with small treats for a long-term fix
Researchers have demonstrated how a non-toxic alternative to lead could form the basis of next-generation solar cells (for example: GOA...