Prototype Transparent Photovoltaic Cell Could Pave the Way to Invisible Solar Panels

An international research team has published details on progress towards "invisible solar panels," showing off a transparent photovoltaic cell which could one day turn buildings' windows into power sources.

"The transparent photovoltaic cell (TPC) is an invisible solar cell [which works] by passing the visible range light while absorbing harmful UV light to generate electric power," the team explains of the prototype it has created. "Different from the conventional opaque colors or shapes of solar cells, TPC is transparent to human eyes and which would serve as an invisible power source for the window frames of mobile electronics, displays, and buildings."

The cell is constructed from a glass substrate with a metal oxide electrode and thin layers of titanium dioxide and nickel oxide before adding silver nanowires to act as the second electrode to finish the cell.

In testing, the prototype showed a power conversion efficiency of 2.1 percent — a higher-than-expected result, given that the cell's purpose is to pass as much visible light as possible and focus purely on generating energy from ultraviolet light. It also showed good transmission of visible light, at 57 percent — and, in a final portion to the experiment, proved its capabilities by driving a small motor.

"While this innovative solar cell is still very much in its infancy," notes Professor Joondong Kim of his team's work, "our results strongly suggest that further improvement is possible for transparent photovoltaics by optimizing the cell’s optical and electrical properties."

The paper has been published under open-access terms in the Journal of Power Sources.