Published in Chemistry World, 16 Jul 2009
Chemists in the US have created the first material to exhibit ‘inverse photoconductance’, in which conductance decreases with exposure to visible light. The effect could be exploited to make new types of sensor that can be tuned for different spectral properties and printed directly onto plastic substrates.
Traditional photoconductors increase their conductance when exposed to light, and are typically made of a high-resistance semiconductor. When photons strike the semiconductor’s surface, they impart energy to electrons in the valance or conduction band. These energetic electrons then jump into the conduction band and, combined with the positive hole left behind, boost the semiconductor’s conductivity. […]
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