Last year, Daimler introduced a concept car called the Smart Forvision. All electric, the Forvision had some interesting gee-whiz features, including a solar-paneled roof that combined the energy gathering effects of transparent solar panels with OLED (Organic Light Emitting Diode) lighting.
Daimler had worked with BASF to create the Forvision's design, including the see-through solar roof. Now BASF and Philips have announced that they've made a breakthrough in actually bringing the lighting technology to life.
The two companies have succeeded in sandwiching transparent solar panels with transparent OLED cells, so that a car roof can be covered with a structure that lets in daylight for drivers, and turns opaque when switched on, allowing for diffuse lighting from the ceiling at night, all powered by the solar panels.
OLED lighting cells can be just 1.8 millimeters thick and can be transparent, allowing them to work underneath the solar paneling. The high energy efficiency of OLED light cells allows them to run on energy generated from the solar panels. The companies say the lighting is ready for integration into car roofs, though they haven't announced any production dates, and OLED technology has been expensive to manufacture. Philips has said it is investing in an OLED production line in order to lower the costs.
Daimler, in the meantime, hasn't given any indication that it is going to produce the Smart Forvision with the OLED roof. However, it has an all-electric version of the Smart Fortwo, the Fortwo ED, that might be a possible candidate for integration of the OLED solar roof in future.