19
Photochemistry and Electrochemistry of
Nanoassemblies
P. V. Kamat
19.1
Metal and Semiconductor Nanostructures
Semiconductor and noble metal nanoclusters in the nanometer size regime display many interesting optical, electronic and chemical properties that are sizedependent (see for example, [1–13]). Such nanoscale materials have potential
applications in developing new catalysts [14, 15], nanosensors [16–18], and optoelectronic nanodevices [12, 19–23]. Increasing interest in nanotechnology has
induced a burst of research activity in the area of synthesis and organic functionalization of metal nanoparticles. The size and shape dependent optical and electronic
properties of metal nanoparticles make an interesting case for photochemists and
photobiologists to exploit their role in light induced chemical reactions [24].
Nanoparticles are the building blocks of future nanodevices as they can be assembled as two- and three-dimensional nanostructures using self-assembled, layerby-layer assembly and electrophoretic deposition techniques [25]. By controlling
the preparative conditions of metal or semiconductor colloid precursors and functionalization of these particles with redox or photoactive molecules, it is possible
to tailor the properties of these nanostructures. For example, thin metal oxide
films cast on conducting glass electrodes exhibit interesting photochromic, electrochromic, photocatalytic and photoelectrochemical properties that are inherited
from native colloids [26]. This chapter presents an overview of photochemical and
electrochemical aspects of native and functionalized semiconductor and metal
nanostructures. The discussion on the hybrid assemblies should provide a broad
basis for designing new generation nanodevices.
19.2
Photoinduced Charge Transfer Processes in Semiconductor Nanoparticle Systems
The multidisciplinary research of semiconductor nanoclusters has witnessed exceptional growth during the past decade. By making use of the principles of pho620
Photochemistry and Electrochemistry of
Nanoassemblies
P. V. Kamat
19.1
Metal and Semiconductor Nanostructures
Semiconductor and noble metal nanoclusters in the nanometer size regime display many interesting optical, electronic and chemical properties that are sizedependent (see for example, [1–13]). Such nanoscale materials have potential
applications in developing new catalysts [14, 15], nanosensors [16–18], and optoelectronic nanodevices [12, 19–23]. Increasing interest in nanotechnology has
induced a burst of research activity in the area of synthesis and organic functionalization of metal nanoparticles. The size and shape dependent optical and electronic
properties of metal nanoparticles make an interesting case for photochemists and
photobiologists to exploit their role in light induced chemical reactions [24].
Nanoparticles are the building blocks of future nanodevices as they can be assembled as two- and three-dimensional nanostructures using self-assembled, layerby-layer assembly and electrophoretic deposition techniques [25]. By controlling
the preparative conditions of metal or semiconductor colloid precursors and functionalization of these particles with redox or photoactive molecules, it is possible
to tailor the properties of these nanostructures. For example, thin metal oxide
films cast on conducting glass electrodes exhibit interesting photochromic, electrochromic, photocatalytic and photoelectrochemical properties that are inherited
from native colloids [26]. This chapter presents an overview of photochemical and
electrochemical aspects of native and functionalized semiconductor and metal
nanostructures. The discussion on the hybrid assemblies should provide a broad
basis for designing new generation nanodevices.
19.2
Photoinduced Charge Transfer Processes in Semiconductor Nanoparticle Systems
The multidisciplinary research of semiconductor nanoclusters has witnessed exceptional growth during the past decade. By making use of the principles of pho620