High Photoconductive Response
of Gas-Sensitized Porous
Nanocrystalline TiO<sub>2</sub> Film in Formaldehyde Ambience and
Carrier Transport Kinetics
- Publication date
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Abstract
We propose a gas-sensitized porous nanocrystalline TiO<sub>2</sub> film with a potential application in photovoltaic devices
and report
about the systematic photoconductivity study of it. The quantitative
results show that the gas-sensitized TiO<sub>2</sub> film in formaldehyde
atmosphere exhibits much higher photoconductivity (3–4 orders
of magnitude) and longer carrier lifetime than usual. The intriguing
performance of the gas-sensitized TiO<sub>2</sub> film indicates the
distinct charge carrier transport kinetic courses, whose contributions
to the photoconductivity are shown in a designed flowchart. From the
flowchart, it is clearly found that two electron loss processes, recombination
and electron scavenging, are suppressed for the gas-sensitized TiO<sub>2</sub> film in formaldehyde gas, leading to large improvements of
photoconductivity and carrier lifetime. The results provide the potential
of improving efficiency of photovoltaic devices, and measuring photoconductivity
under target gas appears to be a useful tool for research on photocatalytic
and photoelectrical processes
