The International Year of Light 2015 Celebrates Achievement in Light-Based Technologies Around the World

Did you know that the UN General Assembly declared 2015 as the International Year of Light and Light-based Technologies (IYL 2015)? While many of our blogs are dedicated to celebrating light science and its fascinating applications, it is especially reaffirming to see light technology recognized on the world’s stage. Throughout the year, IYL 2015 has focused on “raising global awareness about how light-based technologies promote sustainable development and provide solutions to global challenges in energy, education, agriculture and health.” Many organizations and sponsors have come together to promote IYL 2015 and provided funding and programming to showcase research, innovative technologies, and projects across the globe. The following are examples of research and innovation coming together to shine a light on two global challenges – namely affordable, efficient solar energy and sustainable lighting for remote communities in Africa.

The first example comes from a team of researchers at the University of Bath in collaboration with scientists in Germany and The Netherlands whose organic semiconductor research promises more efficient and less expensive solar cells. A semiconductor is the key ingredient that helps convert the energy of light directly into electricity in photovoltaic cells. Traditionally, semiconductors have been inorganic compounds largely made from silicon, which means they are difficult to produce and consume a lot of energy during the production process. According to the University of Bath news release, it can take up to a year to ‘pay back’ the energy used in the manufacture of silicon-based solar cells.

Dr. Daniele Di Nuzzo, Research Officer in Physics at the University of Bath and first author on the team’s paper, explains: “Conventional semiconductor devices are tricky to make because they first require the production of crystalline materials. Because of this, they also use up a lot of energy to be produced.” The main advantages of organic semiconductors are that they are less expensive to produce, are more flexible, and can be incorporated into different materials. “For example,” says Di Nuzzo, “… organic semiconducting polymers can be dissolved in a solvent to make an electronic ink to be printed onto a surface.” The disadvantage of organic? “They have a disordered structure and conduct electrical charges less well than silicon,” he says.

This is where doping plays an important role. No, don’t worry: this doesn’t involve Lance Armstrong or Alex Rodriguez. Instead, doping molecules work to improve the electrical properties of organic semiconductors by adding electrical charges to the polymer. The team’s research found that the size and geometrical position of the doping molecule used affects the efficiency of the semiconductor material itself. Study lead, Dr. Enrico Da Como, explains: “The organic polymer consists of a chain of units which is mixed with the doping molecule before it is printed onto a surface. We found that the doping molecule can bind to the polymer in several different orientations, some of which make a more effective semiconductor than others. Our work suggests that if you use a larger doping molecule, you limit the number of ways it can bind to the polymer, making the efficiency of the semiconductor more consistent.” Refining the processes to maximize the efficiency and performance of organic semiconductors is another large step forward for solar energy.

The second example of ‘light done right’ comes from a collaboration that is working to help bring clean, reliable, and affordable light to off-grid African regions. To commemorate their 75th anniversary, the VELUX Group teamed up with Little Sun and the NGO Plan International to launch the Natural Light project, which uses a distribution model similar to micro loan organizations like Kiva to distribute 14,500 donated solar lamps to entrepreneurs in off-gird communities like Senegal, Zimbabwe, and Zambia. By giving local entrepreneurs a stock of Natural Light lamps for free, as well as training to get their business started, the project aims to help locals build profitable, self-sustaining local businesses.

Mariano Arando and Luca Fondello, industrial design students at the University of Buenos Aires in Argentina built the winning design of the Natural Light lamp. They named it so because it uses the natural light of the sun to charge itself – five hours of direct sunlight will fully charge the lithium battery, which will then deliver 25 lm for approximately four hours on the brightest setting, or up 50 hours of light using the lowest setting. It uses a highly efficient Samsung LED with a colour temperature of 5000K (neutral white). The solar panel is made of mono-crystalline SunPower solar cells, which deliver 0.5W at 4.4V.

In their blog article posted on the IYL 2015 website, the designers point out that, “Unfortunately sometimes designers and engineers forget that instead of creating a solution to a problem, they just create new products that have no real purpose and do not solve any problem. [This] project will improve the living conditions of thousands of people and contributing to that leaves you with a good feeling.”

As we count down the last 100 days of IYL 2015, take pause and consider the impressive accomplishments in light science over our relatively short history and, like us at Mission LED, continue to be inspired by the fascinating innovations and applications that are just around the corner. Truly the future has never looked brighter.