100 units of a portable lamp, which uses dye-sensitized solar cells (DSSCs), LEDs and nickel-metal-hydride rechargeable batteries, made by A Japanese research group and a manufacturing company.

The group was led by Hiroshi Segawa, professor at the Research Center for Advanced Science and Technology (RCAST) of the University of Tokyo. It distributed the lamps to two areas affected by the Tohoku Earthquake.

The portable lamp was made by combining (1) a palm-sized DSSC panel developed by the manufacturing company, which has been engaged in research with the research group, (2) a commercially-available LED lamp that can be turned on by pressing the light-emitting part by hand and (3) rechargeable batteries (two AA nickel-metal-hydride batteries).

It is not necessary to replace batteries. By exposing the portable lamp to sunlight during daytime hours, the batteries can be charged with electricity generated by the DSSCs. When the batteries are fully charged, the LED lamp can be continuously lit for about 20 hours.