Philips and BASF have teamed up to develop a new car roof lighting solution using see-through OLED lights.

The energy efficient lights are transparent when turned off, providing a moon roof-like view during the day. And when turned on, the OLED lights only illuminate the inside of the vehicle.

The two companies envision this lighting concept paired with transparent solar cells on the roof.

"This combination allows the driver to enjoy a unique open-space feeling while it generates electricity during the day and pleasantly suffuses the interior with the warm light of the transparent, highly efficient OLEDs at night," said BASF's head of OLED research, Dr. Felix Gorth.

The OLED lights are currently in a concept stage, and no commercial applications have been announced yet.