Skyscrapers with windows as high efficient power sources is becoming a reality with the latest discovery by a group of researchers. Their novel, colour neutral, semi-transparent photovoltaic solar panels have a higher efficiency than other transparent options available.
Solar energy is being harnessed in many different ways and scientists around the world are trying their best to come up with more efficient and cost-effective methods to do that. The Solar tree, Solar panels that works at night and the one which output electricity and thermal energy are some of those interesting novel techniques.
The researchers from the University of Michigan were able to achieve an 8.1% efficiency on a 43% transparent organic carbon-based solar cells, which can be set up as windows on high-rise buildings. These are not based on conventional Silicon but an organic carbon-based material. And they are said to be with a slight greenish tint more like a greyish hue on sunglasses.
Most of these skyscraper windows are made with an outer coating that can absorb some of the solar energy comes its way and then reflect some of it away. A method which helps to keep these buildings cooler and not too bright. Scientists used this idea and made it harness more energy that can later be used on the building’s energy consumption.
According to Yongxi Li, an assistant research scientist in the study, “The new material we developed, and the structure of the device we built, had to balance multiple trade-offs to provide good sunlight absorption, high voltage, high current, low resistance and colour-neutral transparency all at the same time,”
The special material
The organic carbon-based material is said to be absorbing much of the near-infrared wavelengths which is abundant in sunlight. To visible light, it is transparent. And to increase the energy generated from both these ways, scientists created ‘optical coatings’.
They made two versions of the material. The colour-neutral version was made with indium tin oxide electrode and the slightly greenish one which gave a 10.8% efficiency output was made with silver electrode that had a 43% transparency.
The ‘light utilization efficiency’ of these materials was far higher than previously known attempts that resulted in about 2-3 %. In the study, the Silver electrode ones had a 5% light utilization efficiency and the indium tin oxide version had a 3.5% efficiency.
Scientists say that both these materials can be manufactured in a large scale and would be far less toxic than other transparent counterparts. The transparent material can also be placed in between double-glazed panes.
Their hope is to raise the light utilization efficiency to at least 7% and make the photovoltaic cell last for a decade. An efficient technology like this would definitely add an effective use to those sky-high appearances. Wishing them the best of success!
The study has been a combined effort of scientists from the University of Michigan, Soochow University in China, North Carolina State University and SLAC National Accelerator Laboratory. The research has been published in the journal, Proceedings of the National Academy of Sciences.