How can I convert sun heat to electricity using a device can attached to the solar cell panal?

IEEE Spectrum: Silicon Nanowires Turn Heat to Electricity (http://www.spectrum.ieee.org/jan08/5879)
Perhaps all on/in the panels.

Thermoelectric devices (Thermoelectric cooler) will convert heat to elecricity directly. They are horribly inefficient. They can also convert electriicity to heat.