ONE of DNA鈥檚 building blocks has been transformed into a light detector
that鈥檚 twice as sensitive as the sensors in today鈥檚 optical-fibre receivers.
Ross Rinaldi and his team at the Universities of Lecce and Bologna in Italy have
discovered that a chemical derivative of deoxyguanosine is sensitive to
light.
Their discovery might mean that organic components can form the heart of more
efficient optical data networks. Rinaldi says his prototype biomolecular device
works at room temperature鈥攁nd appears to have a working life comparable to
that of photodiodes.
To make the device, the team grew a deoxyguanosine crystal lattice between
thin layers of gold and chromium on a standard microchip base. Rinaldi found
that the crystal behaves like a semiconductor, conducting electric current only
when blue light falls upon on it.
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The team are now trying to work out why the substance behaves in this way,
and plan to report their findings at a conference on molecular electronics in
the Netherlands this September.
Giles Davies, a semiconductor physicist at the Cavendish Laboratory at
Cambridge University, speculates that the organic device might also work as an
ultra-bright light emitting diode as well as a light detector.