While indoor lighting poses unique challenges compared to sunlight, gallium indium phosphide PV (photovoltaic) cells have emerged as surprising frontrunners, achieving a 40% conversion efficiency.
Solar panel technology is making its way indoors to power an array of smart devices, offering a new frontier for energy-efficient solutions. The researchers have explored the potential of photovoltaic (PV) systems to harness indoor lighting, particularly cool white LEDs, a common source of artificial illumination. Indoor lighting presents unique challenges compared to natural sunlight. It is generally dimmer and emits light within a narrower spectrum. While PV solar panels have been designed to convert sunlight into electricity efficiently, they have yet to be optimised for indoor lighting conditions. To bridge this gap, Uli Würfel and his team embarked on a mission to determine the most efficient PV materials for converting non-natural light sources into electrical energy.
The researchers tested eight types of PV devices, ranging from traditional amorphous silicon to advanced thin-film technologies like dye-sensitized solar cells. They evaluated each material’s ability to convert light into electricity, both under simulated sunlight and cool white LED lighting. Surprisingly, gallium indium phosphide PV cells emerged as the frontrunners, achieving an impressive 40% conversion efficiency under indoor lighting. This was particularly unexpected as their performance under sunlight was comparatively modest due to their large band gap. Crystalline silicon, on the other hand, displayed exceptional efficiency under sunlight but proved average when exposed to indoor light.
While gallium indium phosphide shows promise, it currently faces challenges such as high production costs, limiting its potential as a mass-market solution for powering smart home systems. In contrast, perovskite minerals and organic film PV cells offer cost-effective alternatives with more excellent stability under indoor lighting conditions. Additionally, the study uncovered valuable insights into the conversion of indoor light energy, revealing that a portion of it is dissipated as heat rather than being converted into electricity. This knowledge will play a pivotal role in optimising future PV technologies for indoor device power generation.
Integrating solar panel technology with indoor lighting sources opens up exciting possibilities for powering a wide range of smart devices within homes and commercial spaces. As the IoT expands, efficient and sustainable energy sources like indoor PV systems could drive the next wave of personalisation and convenience for connected living spaces.