Mobile devices and cars could soon self charge thanks to transparent solar cells

Imagine putting your phone down in the sunshine and, instead of an alert about overheating, you receive an update to say the device is now fully charged. A new type of glass that can generate solar energy without the need for wires has been developed by researchers in South Korea, and could soon mean that everything from windows in buildings to car windscreens to mobile phones and other devices could effectively become self-charging and even energy positive.

Seamless modularisation

The technological breakthrough, made by a team at the Ulsan National Institute of Science and Technology, involves silicon solar cells that are both transparent enough to maintain the properties of glass and efficient enough at energy generation and transfer for commercial applications.

Dubbed seamless modularisation, the innovation, which was published in the international journal Proceedings of the National Academy of Sciences (PNAS) in August 2024, works through an “all-back-contact” design that places all the necessary components of the solar cell on the back. This ensures unobstructed visibility and eliminates the various aesthetic problems and losses caused by gaps between devices and metal wires. 

High efficiency and glass-like looks

At just 16 cm² the transparent solar cell module was developed by Professor Kwanyong Seo and his research team at UNIST’s School of Energy and Chemical Engineering, with the support of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the equipment and facilities of the UNIST Central Research Facilities (UCRF).

The discovery has a high efficiency ranging from 20% to 14.7% in transmittance while maintaining aesthetics similar to that of a single device, the study’s abstract explains. Having succeeded in using just natural sunlight to charge a smartphone, it has proved that a screen as small as that on a mobile device can be used as an energy source.

An eco-friendly future energy source

Promising “to significantly expand the usability of solar technology”, according to the paper, the implications of the advance are wide ranging, say fellow researchers Jeonghwan Park and Professor Kangmin Lee, presenting “the possibility that transparent silicon solar cells can be used in various industries such as small devices as well as buildings and automobile glass.”

With further research, the advance has “opened a new path for modularization research, which is essential for commercialization of transparent silicon solar cells”, according to Professor Seo, who explained that the development could mean that “transparent solar cells can become a key technology in the eco-friendly future energy industry.”