Scientists elevate quantum dot solar cell world record

Colloidal quantum dots are electronic materials and because of their astonishingly small size (typically 3-20 nanometers in dimension) they possess fascinating optical properties. Quantum dot solar cells emerged in 2010 as the newest technology on an NREL chart that tracks research efforts to convert sunlight to electricity with increasing efficiency. The initial lead sulfide quantum dot solar cells (like RENOGY 200 WATT ) had an efficiency of 2.9 percent. Since then, improvements have pushed that number into double digits for lead sulfide reaching a record of 12 percent set last year by the University of Toronto. The improvement from the initial efficiency to the previous record came from better understanding of the connectivity between individual quantum dots, better overall device structures and reducing defects in quantum dots.

The latest development in quantum dot solar cells comes from a completely different quantum dot material. The new quantum dot leader is cesium lead triiodide (CsPbI3), and is within the recently emerging family of halide perovskite materials. In quantum dot form, CsPbI3 produces an exceptionally large voltage (about 1.2 volts) at open circuit.

"This voltage, coupled with the material's bandgap, makes them an ideal candidate for the top layer in a multijunction solar cell," said Joseph Luther, a senior scientist and project leader in the Chemical Materials and Nanoscience team at NREL. The top cell must be highly efficient but transparent at longer wavelengths to allow that portion of sunlight to reach lower layers. Tandem cells can deliver a higher efficiency than conventional silicon solar panels that dominate today's solar market.

This latest advance, titled "Enhanced mobility CsPbI3 quantum dot arrays for record-efficiency, high-voltage photovoltaic cells," is published in Science Advances. The paper was co-authored by Erin Sanehira, Ashley Marshall, Jeffrey Christians, Steven Harvey, Peter Ciesielski, Lance Wheeler, Philip Schulz, and Matthew Beard, all from NREL; and Lih Lin from the University of Washington.

The multijunction approach is often used for space applications where high efficiency is more critical than the cost to make a solar module. The quantum dot perovskite materials developed by Luther and the NREL/University of Washington team could be paired with cheap thin-film perovskite materials to achieve similar high efficiency as demonstrated for space solar cells, but built at even lower costs than silicon technology -- making them an ideal technology for both terrestrial and space applications.

"Often, the materials used in space and rooftop applications are totally different. It is exciting to see possible configurations that could be used for both situations," said Erin Sanehira a doctoral student at the University of Washington who conducted research at NREL.

The NREL research was funded by DOE's Office of Science, while Sanehira and Lin acknowledge a NASA space technology fellowship.

NREL is the U.S. Department of Energy's primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

What not to store in the garage

So you have a garage and it is everyone’s favorite place to dump things that you don’t need. Though your garage can be used to store things but they are not meant for keeping anything and everything you like. You never give it a thought on what should be kept and what should not be kept in the garage. It should not be merely a dumping place, but you should keep things there in a manner that you can use them again. You store something to be used again and not to totally destroy it and the garage as well.

Utility of a Garage

Apart from parking your vehicle, garage has been always used and is still being used just as another store room. There is no harm in storing things. But the point is do you know what things one needs to keep in the garage and what should be kept away? Here are some of the things that you should know should be kept away from the garage.
Food: Most important thing is storing your food. Food attracts a lot of insects and rodents in your garage if you store your food items there. So storing food items somewhere safe would be avoid a lot unwanted insects and rodents out of your house.
Items that you use every day: Items that you need for everyday use should be kept nearby and not in the garage. It will save space of your garage and you can store something else in that space.
Wine: Such beverages should not be stored in the garage because of the varying temperatures. It’s better to keep them in a refrigerator.
Paintings: If you have some valuable items like paintings in your house, then you should never store them in your garage. Moisture or direct sunlight in the garage can destroy the paintings. So it’s always better to store them in a place which is humidity free and away from direct sunlight.
Your important documents: Never keep your important documents in the garage. Just in case there is some leakage in the garage, the water can destroy your documents forever. You can always keep such documents in your study room or bedroom.
Photographs: If memories are so important for you then you should never keep them in the garage. Moisture spoils the pictures and sticks to plastic sometimes. Keep them in the drawers of your bed room instead.
Clothes that are sensitive: Don’t keep your delicate clothes in garage. Their place is in a closet and not garage. Keep your clothes away from moisture, heat or too cold weather to make them use for a long time.
Wooden furniture: We do know that due to heat or cold, things expand and contract. Wooden furniture is no different. Don’t keep your furniture in the garage if you want to save your furniture to be used again.
Paint: With time paint gets ruined if kept without keeping it safe or uncovered. Paint needs to be kept indoors, if you want to use it again in future.
Propane tanks: It’s very risky to keep something so inflammable in your garage. Such things should be kept away from the house.

We never really care before dumping anything in the garage. But as you can see, there are so many things that you need to see before storing anything in the garage. There are certain things that you cannot afford to lose at all, then why risk them by keeping them in the garage. These little points can save a lot of your important stuff.
Some Awareness Is Essential

A little awareness can be helpful in saving your precious things. So never keep anything in the garage before knowing the aftermath of your action. If you have a store in your house other than your garage, then you should keep your important stuff there. You will never get back the things which will get destroyed because of some carelessness. Take a good care of your belongings and keep them safe. Your garage is not meant to keep everything. It’s just for some selected items. If garage has some extra spaces in it then don’t think of simply filling it with not so important stuff. Keep things that are humidity proof, heat proof or cold proof. These are some of the suggestions that you can use to save your items. Rest you know better what you want to do with your things, either to save them or let them get ruined by ignoring the important storing facts.

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5 Trail Camera Tips To Help You Scout More Effectively

Over the past few years, trail cameras ( for example: MOULTRIE PANORAMIC 180I ) have become an extremely important tool for big game hunters all over the world, especially for deer hunters in the United States. However, like any tool, they must be used property in order to realize their full potential. There are a number of pretty common mistakes that most hunters make when first using trail cameras. Luckily, correcting most of those mistakes is relatively easy and doing so can significantly improve the quality of scouting that their trail camera can provide. Today, I’ll share some tips for using a trail camera that I’ve learned the hard way over the years.

Trail Camera Security

Since they are a valuable item that is left unaccompanied out in the woods, an unsecured trail camera can be a very enticing target for a thief. This is especially true when using them on public land. There are three ways to secure your trail camera: by physically locking it to a tree or other mounting device, by placing it in an inconspicuous location where it is less likely to be noticed or stolen, and by registering the camera with the manufacturer and using a security code for operation.

Using some sort of device, like a cable lock, to secure a trail camera is an obvious way to secure your camera from a casual thief. However, it is not foolproof: a determined thief can cut the cable or even cut down the tree to steal the camera (I had this happen to me several years ago). Even if they cannot physically steal the trail camera, an unscrupulous person can still take your memory card or destroy the camera.

A more effective way of securing your trail camera is to locate it in a place where few people are likely to see it. After all, if a thief doesn’t know that the camera is there, he can’t steal it. This means placing the camera in a location far away from roads or other areas where lots of people move through. This has the added benefit of increasing the odds of getting useful photos from your trail camera because generally speaking, locations with lower amounts of human activity have more animal activity, especially of mature bucks.

Finally, some trail cameras have a feature requiring a security code to operate it. Now this won’t necessarily prevent a thief from stealing your trail camera, but if you have the password feature enabled, this can potentially prevent a thief from using your camera in the event that they do steal it. Registering your trail camera with the manufacturer after purchasing it, that can assist in recovery of a stolen camera because the manufacturer will send the camera back to the registered owner if the thief sends it back to the factory to get the password reset.

Minimize Your Signature

A major mistake that many hunters make is not taking precautions to avoid spooking animals while placing or checking a trail camera and end up scaring the very animals they are trying to get photos of. Every time a person enters the woods, no matter how careful they are, they create a disturbance that can disrupt the behavior of animals by the noise they make and the scent that they leave. As time passes after they leave the woods, the evidence of their presence slowly dissipates and animals start to behave normally again.

When placing or checking on a trail camera, it is very important do all of the things that you usually do when hunting to avoid alerting animals in your vicinity to your presence. This includes things like staying downwind of likely deer locations, wearing rubber boots, using a cover scent or scent eliminating spray, not slamming your car door, etc. Don’t forget to take the same precautions with the trail camera itself: after I’m finished handling the camera, I like to spray it down with a scent eliminating spray (just be careful not to get any on the camera lens).

Another trap many hunters fall into is the temptation to check their camera for new photos too frequently. Checking the camera more often means more disruption of the animal routines in the area and therefore less chances of seeing a trophy animal. There are two ways to avoid this: by checking the trail camera no more frequently than once every 7-14 days, or by purchasing a wireless trail camera that can send photos to your cell phone in the form of text messages. Of these two, the wireless trail camera is the least intrusive, but is much more expensive and will only work if there is cell phone service in the area where the trail camera is set up.

Trail Camera Positioning

Proper positioning of a trail camera is probably the single most important factor in getting good photos. One commonly overlooked aspect of orienting a trail camera is the location of the sun relative to the subject of the photograph. For locations in the northern hemisphere, the trail camera should ideally face north. This will ensure that the sun is behind the camera, and help reduce the number of false triggers or “washed out” photos where no details are visible. If it is not possible to point the camera to the north, then face it south. Facing the camera directly west or east is least desired, as this will ensure that the camera is looking directly at the sun as it rises or sets.

Additionally, when emplacing a trail camera, ensure that you trim branches and leaves around the camera. This will ensure that their movement will not accidentally trigger the camera when game is not present. Trimming branches around the camera will also ensure that the photographs are free from obstructions and better allow for easier identification of game in the photographs.

At the same time, ensure that the camera is positioned at an appropriate height. I’ve found that 2-3 feet off the ground works well. A camera emplaced any higher than that must have enough of a downward angle to avoid missing game completely. Remember, most animals aren’t very tall and can walk right by a camera without triggering it if the motion sensor is looking over the top of their head.

A trail camera can be a powerful scouting tool if used correctly. If used improperly, it can actually do more harm than good. Keep these points in mind next time you use your trail camera. Hopefully, you will not have to learn some of these lessons the hard way like I did.

How Online Collaboration Can Help Business and the Environment

Even if the grubby money hungry hounds in corporate don’t believe climate change is real, taking positive action can be extremely profitable – to the planet and your business. In this article, I’m going to talk about how building a corporate structure around sustainability can be lucrative, because when going green puts more green in wallets they’ll listen to the science. From utilising online collaboration tools to downscaling on office space and reducing costs, here are some of the ways businesses can prosper from greenification.

Carbon emissions are costing you

Project management software and collaboration tools allow team members to work from anywhere. This means that employees can work from home and cut the commute from the daily grind, while still working effectively as a team. One TIME article estimated that the average cost of petrol used to regularly commute to work came to roughly £40,000 every ten years. And wouldn’t you rather invest that money in, say, your child’s education or, better still, your retirement? When it comes to the environment, burning through a litre of petrol equates to 2.31kg of CO2 emissions. About 15% of airborne pollution can be equated to car use worldwide.

Why Your Business Should Provide Tuition Reimbursement Benefits to Employees

Employee benefits can be double edged sword. On one hand, it costs businesses lot of money, but on the other hand they can generate loyalty and improve employee performance. The key to succeeding at this is making sure you implement properly and generate good return on investment. Tuition reimbursement is one such benefit that can help businesses of all types attract good employees and retain them eventually helping businesses grow. Granted, it costs significant money to implement tuition reimbursement program with the rising cost of college in the U.S., but if you manage it properly you can get significant tangible and intangible benefits from it.



That is why many large corporations have recently rolled out tuition reimbursement benefits. For example, Starbucks recently launched College Achievement Plan for eligible employees. It is designed for employees who are in their junior and senior year of college, supporting them in finishing their degrees. Employees must be based in the United States and work an average of 20 hours per week or more. Other companies, including Deloitte, UPS and Home Depot have similar programs.

How Can Your Business Benefit from Analytics

Data analytics has taken the business community by storm recently. The rise of powerful computers as well as the amount and variety of data being generated has helped businesses of all types and sizes gather insight into many aspects of their business like never before. These days Google and Amazon can tell you what you will need or where you are likely to go for vacation even before you know it. When done right analytics can help your business grow sales and improve efficiency significantly.



There are various ways in which you can perform the analytics as shown by CAMO. A method called descriptive analytics is the most basic type that analyzes the data from the past to identify patterns. Other forms of analytics include predictive analytics and prescriptive analytics.

What is Descriptive Analytics?

The purpose of descriptive analytics is to analyze and summarize the data from the past and tell you what happened and why. Descriptive analytics is mostly based on standard aggregate functions like average, maximum and mode in databases that require nothing more than grade school math.

Descriptive analytics can be classified into three categories:

1. Event counters such as number of posts and followers on social media
2. Simple mathematical operations like average response time and average number of replies per post
3. Filtered analytics, such as average posts per week from the United Kingdom vs. average posts per week from Japan