Sensor technology has an important effect on many aspects in our society, and has gained much progress, propelled by the development of nanoscience and nanotechnology. Current research efforts are directed toward developing high-performance gas sensors with low operating temperature at low fabrication costs. A gas sensor working at room temperature is very appealing as it provides very low power consumption and does not require a heater for high-temperature operation, and hence simplifies the fabrication of sensor devices and reduces the operating cost. Nanostructured materials are at the core of the development of any room-temperature sensing platform. The most important advances with regard to fundamental research, sensing mechanisms, and application of nanostructured materials for room-temperature conductometric sensor devices are reviewed here. Particular emphasis is given to the relation between the nanostructure and sensor properties in an attempt to address structure-property correlations. Finally, some future research perspectives and new challenges that the field of room-temperature sensors will have to address are also discussed.

Nanostructured Materials for Room-Temperature Gas Sensors

Phthalocyanines: old dyes, new materials. Putting color in nanotechnology

This review paper gives a brief overview on how the outstanding chemical and physical properties of phthalocyanines and phthalocyanine derivatives are being studied and employed in order to construct state-of-the-art technological devices. In a first instance, a short account on how the nature of the phthalocyanine structure and its organization in condensed phases play an important role in their conducting and ultraviolet-visible absorption properties is presented. Consequently, these basic electronic and photophysical features of phthalocyanines allow us to explain why phthalocyanine-based multicomponent covalent or noncovalent donor-acceptor systems may give rise to very interesting photophysical properties, in particular in terms of their ability to generate very long-lived photoinduced charge-separated states. A concise survey on the organization of these multifunctional systems shows how a profound understanding of the morphology at the nanometer-scale of these phthalocyanine-based molecular materials is needed in order to control their physical properties in condensed phases. All the previously mentioned chemical and physical features combined together led us to the description of the latest attempts at incorporating phthalocyanines into photovoltaic devices for solar energy conversion and onto quantum dots for photodynamic therapy or quantum computing. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 75–97; 2008: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20139

Phthalocyanines: from outstanding electronic properties to emerging applications.

We show that organic thin-film transistors have suitable properties for use in gas sensors. Such sensors possess sensitivity and reproducibility in recognizing a range of gaseous analytes. A wealth of opportunities for chemical recognition arise from the variety of mechanisms associated with different semiconductor–analyte interactions, the ability to vary the chemical constitution of the semiconductor end/side groups, and also the nature of the thin-film morphology.

Electronic sensing of vapors with organic transistors

7.1. Synthesis 306 7.2. Spectroscopic and Redox Properties 307 7.2.1. Optical Spectroscopy 307 7.2.2. Redox Properties 310 7.2.3. Other Characterization Methods 312 8. seco-Porphyrazines 312 8.1. Synthesis 312 8.2. Spectroscopic and Redox Properties 312 8.2.1. Optical Spectroscopy 312 8.2.2. Redox Properties 313 8.2.3. Other Characterization Methods 313 9. Conclusions 313 10. Abbreviations 314 11. Acknowledgments 314 12. References 314

G. Guillaud

Papers

Metallophthalocyanines. gas sensors, resistors and field effect transistors