Semiconducting, pyroelectric and chlorine-sensing properties of ytterbium bisphthalocyanine Langmuir–Blodgett thin films

Rickwood, K. R.; Lovett, David; Lukas, B.; Silver, Jack

doi:10.1039/jm9950500725

Cited by 28 publications

(5 citation statements)

References 17 publications

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“…The changes in the conductivity are intense and proportional to the concentration of gas in contact with the sensor. LnPc 2 based sensors can easily detect other gases such as halogens, HCl, H 2 S, SO 2 , NH 3 and a variety of Volatile Organic Compounds (VOCs) [41][42][43][44][45].…”

Section: Resistive Gas Sensorsmentioning

confidence: 99%

“…The nature of the central metal ion coordinated to the Pc rings and the presence of chemical groups linked to the peripheral benzene rings can modify the sensing properties of the phthalocyanines [37][38][39][40][41][42][43][44][45][46][47]63]. The presence of electron-donating substituents such as tertbutyl, phenyl, propyloxy, octyloxy, or crown ether groups decreases the conductivity of the fi lms and modifi es the sensitivity towards oxidant gases [32,[48][49][50].…”

Section: Resistive Gas Sensorsmentioning

confidence: 99%

“…It has been demonstrated that the structure infl uences the sensibility and the kinetics and the responses. Special attention has been paid to the Langmuir-Blodgett technique that offers the possibility of controlling, in a very precise fashion, the thickness and the organization in organic thin fi lms [28,[41][42][43][44][45][46][47].…”

Section: Resistive Gas Sensorsmentioning

confidence: 99%

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New insights into sensors based on radical bisphthalocyanines

Rodrı́guez-Méndez

Saja

2009

J. Porphyrins Phthalocyanines

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The unique semiconducting, optical and electrochemical properties of radical lanthanide bisphthalocyanines make them ideal materials for sensing applications. A variety of chemical sensors have been developed using rare-earth bisphthalocyanine thin films. In this paper, the characteristics of sensors based on bisphthalocyanines are reviewed. The advantages of these sensors with respect to sensors developed using other metallophthalocyanines are discussed. Resistive sensors based on bisphthalocyanines change their conductivity when exposed to a variety of pollutant gases and volatile organic compounds. Because bisphthalocyanines are intrinsic semiconductors, the conductivity of their thin films is higher than the conductivity of metallophthalocyanine thin films. This facilitates the electrical measurements and enhances the sensitivity of the sensors. Optical sensors have also been developed based on the rich optical properties shown by bisphthalocyanines. Films characterized by a bright green color change to red or to blue upon oxidation or reduction. The changes also affect the charge-transfer band associated to the free radical that bisphthalocyanines show in the near infrared region. This band coincides with telecommunication wavelengths, making possible the fabrication of fiber optic sensors where a phthalocyanine film is deposited at one of the ends of the fiber. Electrochemical sensors have been developed taking advantage of the unique electrochemical behavior associated to the one-electron oxidation and one-electron reduction of the phthalocyanine ring. These reversible processes are extremely sensitive to the nature of the electrolytic solution. This has made possible the development of voltammetric sensors able to produce particular signals when immersed in different liquids. In the last part of the paper, the fundamentals and performance characteristics of electronic noses and electronic tongues based on bisphthalocyanines are described. Such devices have been successfully exploited in quality control, classification, freshness evaluation and authenticity assessment of a variety of food, mainly wines and olive oils.

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Section: Resistive Gas Sensorsmentioning

confidence: 99%

Section: Resistive Gas Sensorsmentioning

confidence: 99%

Section: Resistive Gas Sensorsmentioning

confidence: 99%

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New insights into sensors based on radical bisphthalocyanines

Rodrı́guez-Méndez

Saja

2009

J. Porphyrins Phthalocyanines

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“…Phthalocyanines are highly conjugated and symmetrical disk-shaped molecules that possess promising physical and electrical properties, especially when complexed with metal ions, forming the so-called metallophthalocyanines. A potential application of these materials as gas sensors has been demonstrated by several workers. − Using the Langmuir−Blodgett (LB) film technology, one may investigate these macromolecules in an ordered packing arrangement and also seek to enhance their performance in the thin film structure. , Over the years, LB films have been obtained from both substituted and unsubstituted phthalocyanines, − though a comprehensive understanding of their organization at the air−water iinterface is yet to be developed for deriving a packing arrangement−property relationship in the ultrathin LB films.…”

Section: Introductionmentioning

confidence: 99%

“…A potential application of these materials as gas sensors has been demonstrated by several workers. [2][3][4][5][6][7][8][9] Using the Langmuir-Blodgett (LB) film technology, one may investigate these macromolecules in an ordered packing arrangement and also seek to enhance their performance in the thin film structure. 10,11 Over the years, LB films have been obtained from both substituted and unsubstituted phthalocyanines, [2][3][4][5][6][7][8][9] though a comprehensive understanding of their organization at the air-water iinterface is yet to be developed for deriving a packing arrangement-property relationship in the ultrathin LB films.…”

Section: Introductionmentioning

confidence: 99%

Surface Pressure and Surface Potential Isotherms of Ytterbium Bisphthalocyanine Langmuir Monolayers

et al. 1999

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A systematic study is reported on the monolayer characteristics of ytterbium bisphthalocyanine (YbPc2) at the air−water interface, using surface pressure and surface potential isotherms. The influence of various experimental parameters was analyzed, including compression speed, spreading volume, position of the pressure sensor, and subphase temperature. The area per molecule decreased with increasing spreading volumes. Interestingly, the position of the Wilhelmy plate affected the pressure−area isotherms, which does not occur for traditional aliphatic compounds. No significant influence from the subphase temperature was detected. Upon varying the compression speed, the surface potential curve and the collapse pressure were affected, even though the area per molecule remained practically the same. When these monolayers with distinct dipole moments were transferred onto a gold-coated glass substrate, the resulting multilayer LB films exhibited the same surface potential, probably due to molecular rearrangement upon transfer.

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Heteroleptic Rare Earth Double-Decker Complexes with Porphyrinato and 2,3-Naphthalocyaninato Ligands − Preparation, Spectroscopic Characterization, and Electrochemical Studies

Jiang

Liu

Cheng

et al. 2001

Eur. J. Inorg. Chem.

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A series of RE(Nc)(TBPP) (1−12) complexes [RE = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm; Nc = 2,3‐naphthalocyaninate; TBPP = meso‐tetrakis(4‐tert‐butylphenyl)porphyrinate] and Eu[Nc(tBu)4](TClPP) [Nc(tBu)4 = tetra(tert‐butyl)‐2,3‐naphthalocyaninate; TClPP = meso‐tetrakis(4‐chlorophenyl)porphyrinate] (13) have been prepared by a one‐pot procedure which involves the treatment of RE(acac)3·nH2O (acac = acetylacetonate) with the corresponding metal‐free porphyrins and naphthalonitriles in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in n‐octanol. These novel double‐deckers have been spectroscopically characterized. A one‐electron reduction and three one‐electron oxidations have been revealed by electrochemical methods. The potentials of all these processes depend linearly on the ionic radii of the central metal ions, giving a relatively large potential difference (0.50−0.57 V) between the first oxidation and the first reduction processes.

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Semiconducting, pyroelectric and chlorine-sensing properties of ytterbium bisphthalocyanine Langmuir–Blodgett thin films

Cited by 28 publications

References 17 publications

New insights into sensors based on radical bisphthalocyanines

New insights into sensors based on radical bisphthalocyanines

Surface Pressure and Surface Potential Isotherms of Ytterbium Bisphthalocyanine Langmuir Monolayers

Heteroleptic Rare Earth Double-Decker Complexes with Porphyrinato and 2,3-Naphthalocyaninato Ligands − Preparation, Spectroscopic Characterization, and Electrochemical Studies

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