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Category Archives: Solar Technical

Bright future for solar cell technology

Harnessing energy from the sun, which emits immensely powerful energy from the center of the solar system, is one of the key targets for achieving a sustainable energy supply.

Light energy can be converted directly into electricity using electrical devices called solar cells. To date, most solar cells are made of silicon, a material that is very good at absorbing light. But silicon panels are expensive to produce.

Scientists have been working on an alternative, made from perovskite structures. True perovskite, a mineral found in the earth, is composed of calcium, titanium and oxygen in a specific molecular arrangement. Materials with that same crystal structure are called perovskite structures.

Perovskite structures work well as the light-harvesting active layer of a solar cell because they absorb light efficiently but are much cheaper than silicon. They can also be integrated into devices using relatively simple equipment. For instance, they can be dissolved in solvent and spray coated directly onto the substrate.

Materials made from perovskite structures could potentially revolutionize solar cell devices, but they have a severe drawback: they are often very unstable, deteriorating on exposure to heat. This has hindered their commercial potential.

The Energy Materials and Surface Sciences Unit at the Okinawa Institute of Science and Technology Graduate University (OIST), led by Prof. Yabing Qi, has developed devices using a new perovskite material that is stable, efficient and relatively cheap to produce, paving the way for their use in the solar cells of tomorrow. Their work was recently published in Advanced Energy Materials. Postdoctoral scholars Dr. Jia Liang and Dr. Zonghao Liu made major contributions to this work.

This material has several key features. First, it is completely inorganic – an important shift, because organic components are usually not thermostable and degrade under heat. Since solar cells can get very hot in the sun, heat stability is crucial. By replacing the organic parts with inorganic materials, the researchers made the perovskite solar cells much more stable.

“The solar cells are almost unchanged after exposure to light for 300 hours,” says Dr. Zonghao Liu, an author on the paper.

All-inorganic perovskite solar cells tend to have lower light absorption than organic-inorganic hybrids, however. This is where the second feature comes in: The OIST researchers doped their new cells with manganese in order to improve their performance. Manganese changes the crystal structure of the material, boosting its light harvesting capacity.

“Just like when you add salt to a dish to change its flavor, when we add manganese, it changes the properties of the solar cell,” says Liu.

Thirdly, in these solar cells, the electrodes that transport current between the solar cells and external wires are made of carbon, rather than of the usual gold. Such electrodes are significantly cheaper and easier to produce, in part because they can be printed directly onto the solar cells. Fabricating gold electrodes, on the other hand, requires high temperatures and specialist equipment such as a vacuum chamber.

There are still a number of challenges to overcome before perovskite solar cells become as commercially viable as silicon solar cells. For example, while perovskite solar cells can last for one or two years, silicon solar cells can work for 20 years.

Qi and his colleagues continue to work on these new cells’ efficiency and durability, and are also developing the process of fabricating them on a commercial scale. Given how quickly the technology has developed since the first perovskite solar cell was reported in 2009, the future for these new cells looks bright.



Renewable energy need of the hour

Viet Nam’s ever increasing demand is driving the development of renewable energy to help ensure the nation’s energy security, while protecting the environment.

This was revealed during a recent workshop held in HCM City to discuss measures to develop renewable energy in the nation’s southern provinces and cities.


An engineer assembles solar panels at Tan Nhut Secondary School in HCM City’s Binh Chanh District.

Viet Nam is expected to consume seven times more energy next year than in 2010, and is likely to become a coal importer for energy generation after 2015, according to Ly Ngoc Thang, Deputy Director of the Centre for Renewable Energy and Clean Development Mechanisms under the Energy Institute.
An annual 13–15 percent increase in energy demand is estimated.
The country’s aggregate energy demand is predicted to reach 167 million tonnes of oil by 2030, well beyond its production capacity of 50–62 million tonnes of coal and 20–22 million tonnes of oil.
As a result, Viet Nam’s residential and business customers have begun to embrace solar and other forms of renewable energy, and this demand is forecast to rise four-fold by 2030.
Thang emphasised the need to develop renewable energy sources to gradually replace the use of fossil fuels such as coal, oil and gas.
Other participants suggested that apart from wind energy, Viet Nam should focus on other sources of renewable energy, such as solar, biogas and biomass.
With regular winds, over 3,300 kilometres of coast and 2,000-2,500 hours of sunlight every year, the country has great potential for producing energy.
Viet Nam, however, has only begun exploring the use of its promising bio-gas, wind power, solar power, and geothermal electricity resources.
Further, special attention has been given to researching and developing solar and wind energy as a replaceable source of fuel for the country.
According to the Energy Institute, a map tracking wind resources, jointly created by the Ministry of Industry and Trade and the World Bank, is expected to be completed by 2015, hopefully aiding projects seeking to create wind generated power.
However, energy development projects in Viet Nam, in general, and projects in studying and applying solar energy, in particularly, are still operating on small scales and suffer from a lack of applications as a result of financial difficulties.
Currently, HCM City has some 10 million residents who produce between 8,000 – 9,000 tonnes of municipal solid waste (MSW) per day, thus offering an opportunity to operate thermal plants and produce several valuable materials, participant said.
Nguyen Trung Viet, a climate change expert in HCM City, said MSW could see large economic benefits if the city paid attention to waste treatment and recycling technologies.
An estimate of more than 1 billion KWh of electricity could be produced each year from over 7,000 tonnes of waste produced each day in the city.
However, 95 per cent of this waste is currently dumped at dumping sites.
He called for State incentives to create more favourable conditions for investors in this field, such as developing capital support and price subsidy policies.
Experts at the workshop also called for clearing bottlenecks in administrative procedures and infrastructure for the sector’s development.
Source: VNS

Different kinds of solar power systems

There are several types of solar power systems that are used in homes. Let’s discover the most common.

Solar Direct (or Day-Use Solar)
These systems are intended to be used only when the sun shines. There are no storage batteries, so as soon as the sun goes away, the power stops. These systems are great for certain water pumping applications, venting fans, and certain electronics. Rare in application, they are very affordable and easy to install.

DC System with Batteries
These systems are great for small electronics that need to run day or night. Often times you’ll see these systems employed on highway sign lights, gate openers, and communication boxes. Simple and affordable these systems have a wide variety of uses and are perfect for remote locations that require low voltage.


Hybrid Solar-Generator Systems
For off-grid and back-up power applications, most folks turn to a hybrid system. The hybrid system usually consists of a PV array, a charge controller, a battery bank, an inverter, and sometimes a tertiary power source such as a wind turbine or a gas generator. These systems are fairly complex and require a high level of expertise to design and install. With the popularity of off-grid living, however, there are more and more packaged systems for people to choose from. These systems will provide power if the grid shuts down and can still sell power back to a grid if desired.

The biggest disadvantage of these systems is the cost and complexity. The battery bank requires regular maintenance and must be replaced long before the panels are done generating. They are also fairly expensive. These costs, however, are often a better alternative to the cost and hassle of bringing in grid power to remote locations.

Off-Grid Solar Dependent Systems
For cheap power in remote locations, often these systems are the only choice. They generally consist of a small battery bank, a charge controller, and a solar array. People with these systems choose to use all DC appliances so as to avoid the cost and inefficiency of inverters. These systems have the advantage of lower initial cost. The batteries are still an issue for maintenance cost. And there is no backup power if weather doesn’t allow the panels to charge the batteries.

Grid-Tied Solar Systems
This is the easiest and most popular way to get started in PV power. These systems simply tie into your existing home power system and the utility grid. If your array generates more energy than you use, the energy is sold back to the power grid and creates a credit for you. The advantages of these systems are the relative simplicity and lower initial cost. A system like this typically requires a few panels, some wiring boxes and disconnects, and an inverter. The inverter converts the electricity from your panels to power that your home and the grid can use.


This system also requires an interconnection agreement with the local utility. This outlines just how the connection to the grid should be made and what the inspection schedule is. It is generally advisable to get your power company involved early on for a grid-tied system. Since there are often incentives and rebates in place from the state and the utility, it’s well worth the call.

Advantages of a Grid-Tied System
•Initial Cost: The upfront cost of purchasing a system that would provide for a home’s entireelectrical needs can be very high. With variable climate and weather conditions across the globe, the use of off-grid systems requires expensive batteries. Off-grid systems generally require a secondary power source, such as a gas generator, to provide backup power which adds significant cost to the system. Grid tied systems are much cheaper than off grid
•Operating Cost: The maintenance cost of grid-tied systems is very low. Solar panels routinely have 20-25 year warranties and some of the panels created in the 1950’s as part of NASA’s space program are still operational. Batteries associated with off-grid systems require regular maintenance and have a much shorter life than the panels. Backup generators also require significant maintenance and access to a cheap and reliable fuel source.
•Reliability: Grid-tied systems are relatively simple and can have virtually no ‘down time’ where the customer will be without electricity. The increased complexity of battery and generator backup systems often leads to significant down time and can be frustrating to a home owner. Often poor weather that leads to little energy collected from the sun also means decreased battery and generator performance.
•Flexibility: Having an alternative energy source AND a utility source means you can design your system to meet whatever needs you have now and still have the flexibility to increase the system size later. It also allows you to change your system parameters to meet your different needs in the future.


On-Grid Vs. Off-Grid Solar Power Systems

Ready to cut the ties and go off-grid?

Have you considered going completely energy independent with a solar power system?  That is, do you long for going off-grid, free from the expensive rates of utility companies?  I had always thought that off-grid was clearly the way to go, until I did a bit more research.

There are a number of pros and cons for you to consider when implementing a solar power system that will take you off-grid.  First, let’s review the three types of solar power systems:

1. On-Grid Battery Solar Power System
2. On-Grid Solar Power System without Battery
3. Off-Grid Solar Power System

With an on-grid battery system, a back-up battery is included as part of the solar power system.  Batteries can store excess energy generated by the solar panels, and even send the surplus electricity out to the grid.  Of course, the system is connected to the electricity grid which is why it is called “on-grid.”  The solar panel system includes solar panels, a charge controller, battery, inverter, AC service entrance and AC subpanel, and a utility meter.

You can still stay on-grid without a battery, however.  These solar power systems are the simplest and least expensive to set up.  All that is included is the PV array, an inverter, AC service entrance and utility meter.  Your system is connected to the grid, but there is no battery back-up.  The obvious drawback is that when power goes out in your area, your solar power system will also shut down.

Finally, there is the off-grid solar power system.  There is no tie-in to the electricity grid.  Batteries are required as part of the system in order to store excess energy.

If your home is in the woods, you may need to be off-grid

Turning to a comparison of on-grid vs. off-grid solar power systems, there are clear advantages and disadvantages to each of these.

Off-grid systems are the only way to go if you live in a remote area where there are no utilities.  In fact, you can get a better deal on rural properties that are not connected to the grid because of the expense of running lines out to the home.

But, if you have the ability to connect to the grid, why wouldn’t you?  First and foremost is the idea of independence from utilities.  No more worries about rate increases.  If the power goes out, your lights and refrigerator (and television and radio) are not affected.  Second, due to the cost of an off-grid system, many homeowners find themselves forced to conserve energy rather than expand the system to generate more power.  This is very appealing to the environmentally-minded.

What are the down-sides for going off-grid?  Instead of the utility company maintaining your system, you’ll be doing it all yourself.  Batteries will have to be replaced (about every 5-15 years) at a cost of at least $1000.  In addition to the cost of the batteries is the inefficiency, which increases as the batteries age.  They start out at about 90% efficiency.  Moreover, when you’re not connected to the grid, excess energy that is generated is not fed out to the utility to give you an energy credit (this can happen with on-grid systems).  Off-grid systems must use the surplus or lose it.  Finally, most off-grid systems include a back-up generator, which can be very expensive.

None of this is to say that you should not go off-grid.  My in-laws have been living off-grid for almost 25 years and just love it!  My father-in-law is very much a do-it-yourself kind of person.  If you enjoy convenience, however, going off-grid may not be for you!




Hybrid Organic Solar Cells Now More Efficient

Success greets the research team of National Research Council’s National Institute for Nanotechnology (NINT) and the University of Alberta. The plastic solar cells have now an operating life of 8 months instead of mere hours.


And they are low-cost, environmentally efficient, unsealed plastic dollar cells – a green energy source. Developing economically viable plastic solar panels and to produce them in large scale has been the long time goal for the scientists as the cost of ultra high-purity silicon used in the traditionally manufactured solar cells is quite prohibitive. These are the solar cells of future – to be available to common man easily. A University of Alberta-NINT team has been focusing on this for quite some time.

Prototype solar cell:
A multi-disciplinary team has been successful in developing a prototype solar panel. It was operating at high capacity for about 10 hours. After that, problems developed within which reduced the efficiency of solar cells. They found that electrode’s chemical coating was the root cause of the problem. For past few months, work has been going on to correct this problem.

Role of electrode:
Producing power from solar cells is the key responsibility of electrodes and the research team found that the unstable chemical coating started leaking around the circuitry of the solar cell and reduced production capacity. They developed a new coating which solved this problem.

New polymer coating:
The team led by David Rider, consisting of Michael J. Brett, Jillian Buriak from U of A-NINT has been successful in developing a durable and longer lasting coating of polymer for the electrode which stopped the chemical leaking that reduced the production capacity. This new polymer coated electrode makes the solar cell work at high capacity continuously.

Success story:
At the time David Rider and colleagues presented their research paper in Advanced Functional Materials on June 22, 2010, the solar prototype cell had performed already for 500 hours at high capacity. In the highly competitive field of plastic solar-cell technology, this research by U of A-NINT team is considered to be a great achievement. And the cell continued to work for 8 months altogether before being damaged in transit between laboratories.

The future looks bright for hybrid organic solar cells. In Rider’s words “Inexpensive, lightweight plastic solar-cell products, like a blanket or sheet that can be rolled up, will change the solar energy industry”.


Breakthrough in Thin-Film Solar Cells

Scientists at Johannes Gutenberg University Mainz (JGU)  have come out with positive news about increased efficiency of thin-film solar cells. As we know that scientists are trying to increase the efficiency of the solar cells so that they can be considered as serious alternative to the fossil fuels.


Researchers at Johannes Gutenberg University Mainz (JGU) too are working at this angle. They opted for the computer simulations to probe deeper into the indium/gallium combination to increase the efficiency of Copper indium gallium (di)selenide (CIGS) thin-film solar cells. Till now CIGS has shown only about 20% efficiency though theoretically they can attain the efficiency levels of 30%.

Advantages of CIGS:
CIGS cells are cheaper than their counterpart silicon cells due to lower material and fabrication costs resulting in lowered manufacturing costs. CIGS has direct band-gap material therefore they exhibit a very strong light absorption tendency, and only 1-2 micrometers of CIGS is enough to absorb most of the sunlight. Conventional silicon photovoltaic cells are rigid but CIGS cells are flexible. Thin-film solar cells are slowly topping the popularity chart of solar market.

Working on the Efficiency of CIGS: Currently CIGS cells are showing efficiency of around 20%. These cells absorb sunlight through a thin layer made of copper, indium, gallium, selenium, and sulphur. The scientists at Mainz University headed by Professor Dr Claudia Felser are exploiting the computer simulations to find out the properties of CIGS. This research is a part of the comCIGS project. This project is financed by the Federal German Ministry for the Environment, Nature Conservation, and Nuclear Safety (BMU). The researchers are concentrating on the optimum proportion of indium/gallium puzzle. What ratio of indium/gallium would be ideal to increase the efficiency of CIGS? It was discovered earlier that the desired ratio should be 30:70, in practice; the highest efficiency level has been obtained with the exactly opposite ratio of 70:30.

Christian Ludwig who is the member of the Professor Felser’s team worked on the calculations using a hybrid method. This hybrid method included a combination of density functional calculations and Monte Carlo simulations. Dr Thomas Gruhn is the head of the theory group in the Prof. Felser’s team. He says, “Density functional calculations make it possible to assess the energies of local structures from the quantum mechanical point of view. The results can be used to determine temperature effects over wide length scale ranges with the help of Monte-Carlo simulations.”

Homogeneity of the material is the key to high efficiency:
Scientists find out that the indium and gallium atoms are not distributed evenly in the CIGS material; there is a phase when indium and gallium are completely separate. This separation happens at just below room temperature. Researchers also tried out various combinations of temperatures and discovered that the higher the temperature, the more homogeneous the material becomes. The more the lack of homogeneity of the gallium-rich material the lower the efficiency levels of gallium-rich CIGS cells. This phenomenon is discovered for the first time by Prof Felser’s team. The team also discovered a better way to manufacture CIGS solar cells. The research team says if gallium rich material is produced at higher temperatures, the material is notably more homogeneous. For maintaining the homogeneity, the gallium rich material should be cooled down rapidly.

Glass is used as substrate for solar cells. Glass has always restricted process temperatures. But Schott AG has been successful in inventing a special glass with which the process temperature can be increased. Naturally the cells would be more homogeneous. This would lead to the production of cells with a much greater efficiency level. Gruhn says, “We are currently working on large-format solar cells which should outperform conventional cells in terms of efficiency. The prospects look promising.”


The Ultimate Solar Cell?

The ultimate step in utilizing solar power  is to convert maximum energy from sun into electricity. This will make solar power highly cost-advantageous compared to other traditional power sources. Capturing energy wasted as heat from the sun can increase solar conversion efficiency greatly. Research funded by the U.S. Department of Energy is on-going to make this happen.


Not all solar energy utilized:
Actually only about 31% of solar energy is converted into electricity. The rest of the energy is not able to be harnessed as it becomes heat – as ‘hot electrons’ – which is lost very quickly because electrons cool down very fast. Capturing almost all solar energy and converting to electricity is the goal of the ‘ultimate solar cell’.

Utilizing the hot electrons:
Since half the solar energy is lost as heat, the first step will be to slow down the cooling rate of these electrons. The second step will be to capture the hot electrons and use them before the heat energy gets dissipated and lost. And harness the heat energy taking the electrons out via a conducting wire with minimal energy loss.

Semiconductor nanocrystals – quantum dots:
Quantum dots play a pivotal role in the transfer of hot electrons. The research showed that the hot electrons can be transferred to a titanium dioxide electron conductor with the help of photo-excited lead selenide nanocrystals (quantum dots). The aim is to minimize energy loss by having the most effective conductor wire. This will allow the fast removal of electrons from the solar cell before they cool down.

Solar power – the best energy source:
With growing awareness of dwindling sources of fossil fuels, green, environmentally friendly, bio-renewable energy sources are beacon lights of energy sources in future. Solar energy will be the most efficient and common source of such energy. This research is an important step in the creation of the ultimate solar cell.


Carbon-based Solar Cells

Solar panels need silicon for absorption of light. Silicon doesn’t come cheap.This cost-factor is preventing people from using solar energy  on a large scale. Scientists utilize another substance i.e. ruthenium for solar cells. Rutheniumcan is cheaper than silicon but ruthenium is a rare metal on Earth. It is as rare as platinum.


Naturally it can’t be available for mass production. Compared to silicon, carbon is cheap and abundant. The graphene, another form of carbon, is capable of absorbing a wide range of light frequencies.

Graphene is a single sheet of carbon, one atom thick. Graphene has potential to be utilized as an effective, less toxic and cheaper than other alternatives for solar cells. Chemists at Indiana University Bloomington are trying to come up with a better alternative than silicon. If successful, this can be a path breaking discovery.

Other people too took this initiative of using carbon sheets for solar power. But they encountered some hurdles. They used the graphene form of carbon for solar cells. Grephene is akin to graphite used in pencil lead. Graphene absorbs a wide range of light frequencies. Scientists have found large sheets of graphene to be too unmanageable to work with. Large sheets are sticky and get attached with other sheets. Now Indiana University Bloomington researchers are trying to deal with this problem. They are trying to develop non-sticky graphene sheets that are stable. They are putting their efforts on “attaching a semi-rigid, semi-flexible, three-dimensional sidegroup to the sides of the graphene.” They know how to derive energy from carbon. Now chemists from Indiana University Bloomington are graduating to the next logical step i.e. conversion of that energy into electricity. If everything will turn out alright then carbon can be an alternative to expensive silicon and ruthenium, which is as rare as platinum.

Chemists and engineers kept on trying to work out a solution for the stickiness of graphene. They devised many methods for keeping single graphene sheets separate. Till now the most effective solution prior to the Indiana University Bloomington scientists’ experiment has been breaking up graphite (top-down) into sheets and wrap polymers around them. But this method has its own disadvantage. Those graphene sheets are too large for light absorption for solar cells. Indiana University chemists devised a completely new method for carbon sheets. They utilized a 3-D bramble patch between the carbon sheets. This method helped the scientists to dissolve sheets containing as many as 168 carbon atoms. They are successful in making the graphene sheets from smaller molecules (bottom-up) so that they are uniform in size. Till now, it is the biggest stable graphene sheet ever made with the bottom-up approach. Chemist Liang-shi Li, who led the research, tells us, “Our interest stems from wanting to find an alternative, readily available material that can efficiently absorb sunlight. At the moment the most common materials for absorbing light in solar cells are silicon and compounds containing ruthenium. Each has disadvantages.”

Li is of the opinion, “Harvesting energy from the sun is a prerequisite step. How to turn the energy into electricity is the next. We think we have a good start.” Other members of the project team are Ph D students Xin Yan and Xiao Cui and postdoctoral fellow Binsong Li. This project is financed by the National Science Foundation and the American Chemical Society Petroleum Research Fund.


Self-Assembling Solar Cells

What can a scientist do with salad dressing apart from telling you that it increases the taste of salad manifold? But that’s the beauty of this profession. As Newton could give some theories when he saw an apple falling from a tree, salad dressing can inspire scientists towards a brand new type of solar cells.

The researchers managed to create a cheap, efficient and very simple method of making solar cells. The USP of these solar cells is that they self-assemble on a variety of substrates. The new technique draws parallel from the fact that oil and water don’t mix at all. Another unique fact is forces the elements of electronic components for example solar cells assemble themselves at the boundaries between the two types of liquids. This work was recently published in Proceedings of the National Academy of Sciences (PNAS).

University of Minnesota researchers used a number of other methods to create solar cells. It is believed that the technology can be used on commercial scale too. This method has one more benefit that it can force components to self-assemble onto a range of substrates, and not just a select, expensive few.

Till now scientists are applying the use of gravity on such mechanisms. Many lines are engraved on a substrate that was put inside a liquid. Now various electronic components settle down at designed locations. But such methods have their own limitations. They face problems like low yields, and low concentration. Therefore commercial application of such a mechanism was almost impossible. UM expert Heiko Jacobs, the leader of the research team, expresses his opinion, “That’s what we tried for at least two years and we were never able to assemble these components with high yield – gravity wasn’t working.”

He explained his innovative approach further, “Then we thought if we could concentrate them into a two-dimensional sheet and then have some kind of conveyor belt-like system we could assemble them with high yields and high speed.”

The researchers constructed a system at the boundary between water and oil. The substrate is dipped into the liquid, and then gently pulled out. Small components settle down into place, and the method is enormously effectual. The research team was successful to fit about 64,000 elements on a substrate in less than three minutes.

University of Washington in Seattle Nanoengineering Professor Babak Parviz explains, this work is a “clear demonstration that self-assembly is applicable across size scales. Self-assembly is probably the best method for integrating high-performance materials onto unconventional substrates.” Currently the UM team is trying to find out the minimum and maximum sizes that can be produced for electronic components. In short, we can say that the technology could transform the solar cell industry in that it allows for the large-scale assembly of high-quality electronic components.

The technology can be utilized for the highly efficient solar cells that can be built quickly and cheaply on various materials.


Solar Cells To Be Printed Like Newspaper

Sunlight is a non exhaustible source of energy without contributing greenhouse gases to the atmosphere. Still it is miles away from replacing the fossil fuels. Many reasons can be sited. One of its biggest disadvantages is it is still out of reach for the common man and it has a long break-even period.

Unless a product or service is embraced by masses it can’t be treated as alternative source to fossil fuels. But scientists are tirelessly working on solar cells. It is believed that solar cells could soon be produced more cheaply using nanoparticle “inks”. These nanoparticles can help in printing solar cells like newspaper or painted onto the sides of buildings or rooftops to absorb electricity-producing sunlight.

Brian Korgel along with his team is working on this low-cost, nanomaterial solution that can replace the current photovoltaics. Brian Korgel is a chemical engineer at University of Texas at Austin. He is quite hopeful that his new technique coupled with different manufacturing processes will lower the price of solar cells to one tenth. Korgel outlines the needs of cheaper solar cells in the market, “That’s essentially what’s needed to make solar-cell technology and photovoltaics widely adopted. The sun provides a nearly unlimited energy resource, but existing solar energy harvesting technologies are prohibitively expensive and cannot compete with fossil fuels.”

Korgel is utilizing the light-absorbing nanomaterials. Their specialty is that they are 10,000 times thinner than a strand of hair. Their microscopic size makes it possible to attain higher-efficiency devices. The inks could be printed on a roll-to-roll printing process. They can use a plastic substrate or stainless steel for printing. It seems that this type of ink could be used to paint a rooftop or building and it doesn’t look like a tall claim.

Korgel vouches for his idea, “You’d have to paint the light-absorbing material and a few other layers as well. This is one step in the direction towards paintable solar cells.”

Copper indium gallium selenide or CIGS are used for the development of the solar cells. These materials are cheaper in comparison to current materials utilized in the solar cells and easy on environment too. Korgel points out the superiority of his materials over conventional material, “CIGS has some potential advantages over silicon. It’s a direct band gap semiconductor, which means that you need much less material to make a solar cell, and that’s one of the biggest potential advantages.”

There is a catch though. This project team has been able to achieve only one percent efficiency till now. They need to meet the target of ten percent at least. Korgel too feels the same, “If we get to 10 per cent, then there’s real potential for commercialization. If it works, I think you could see it being used in three to five years. He also explained that these links are semi transparent and apart from roofs they could be pasted on the windows too.”