Some researchers at the National University of Singapore developed an energy generator that utilizes a combination of light and shadow to produce electricity. The SEG in use to power an electronic watch, Image courtesy of the Royal Society of Chemistry.


As time passes, more people are concerned about the environment; innovation follows.  A move away from fossil fuels is the direction. Nature based energy scavenging being pushed at every front, water, air, and the sun. However, nobody before the scientists at the National University of Singapore has thought of creating electricity with shadow. Not only did the researchers at the NUS conceptualized, but they pursued and built a panel that utilizes a balance of light and shadow to generate electricity.


Called the Shadow-effect Energy Generator or SEG, the device is a panel of silicon lightly coated in gold, which is said to harvest electricity through a contrast of lit areas and shadowed areas in an environment that are poorly lit. According to the researchers, the generator produces 0.14 microwatt for every square centimeter when exposed to as little sunrays as 0.001.


SEG is not the first generator using silicone. In fact, there are solar cells also made of silicone. Just like in a solar cell, when SEG is illuminated, the electrons of the silicon are energized. Then those electrons migrate from the silicone to the gold metal surface, creating a relatively high voltage depending on the level of shadow. The team of scientists found that to stabilize the system, and the SEG should be half lit and half shadowed. With the balance of high and low voltage, the electrons inside the system migrate, making it possible to power a small device when the system is run through an external circuit. With 8 SEGs the researchers were able to power an electronic watch.


In their publication, the confident researchers stated that the SEG could perform 200 times better than the common silicon solar cell on the market when put in the same shadowy conditions. They also believed that the technology could be used to power sensors in movement-activated devices where the devices track shadows. Meanwhile, the team must test other metals since the use of gold could make the SEG too expensive to produce. One thing for sure, the discovery promises a future where we can generate clean energy even indoors.


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