Development and optimization of porphyrin gas sensing LB films

Richardson, T.; Dooling, Colin M.; Jones, Liza T; Brook, R.A.

doi:10.1016/j.cis.2005.04.009

Cited by 64 publications

(34 citation statements)

References 12 publications

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“…The Soret band in the film is broader than in the solution with an average bandwidth of 168 nm compared to 142 nm in solution. This is attributed to the crystal field effect for the relatively closely packed porphyrin molecules in the thin film assembly 9 . Following the transference of H 2 TPP onto a quartz plate, the Soret and Q bands were studied by exposing the samples (LB and LS) to the gas.…”

Section: Uv-vis Absorption Spectra Of Solution and Ls Filmmentioning

confidence: 99%

“…These systems were studied in different alcohol atmospheres (methanol, ethanol and propanol) and their effect on optical absorbance was analyzed. Also, Richardson and co-workers 9 have achieved a fast response time for calixarene/ porphyrin LB films which can be potentially applied as NO 2 organic sensing material. Figure 7 shows the difference between two films formed by LB and LS, indicating different intensities in absorbance and thereby reflecting on the thickness of each formed film, by considering that absorption intensity is proportional to thickness -Beer's law.…”

Section: Uv-vis Absorption Spectra Of Solution and Ls Filmmentioning

confidence: 99%

“…Based on the lower than expected area/molecule values, it can be concluded that in general the material must form multilayer stacks in which the structure and stability of the film (collapse 40 mNm -1 ) is governed mainly by molecular packing rather than by hydrophilic/ hydrophobic interactions [1][2][3]7 .The exposure of porphyrins to oxidizing or strong reducing gases induce dramatic change in the UV-visible absorption spectrum (Soret and Q bands) that are associated with π → π* transitions and provide the basis for a remarkably interesting gas sensing capability 8,9 . The organization of supramolecular assemblies of H 2 TPP films and its derivatives are dependent of subphase temperature and subphase modifications [2][3]7 , such as the addition of different electrolytes 7 or changes in pH 10 .…”

Section: Introductionmentioning

confidence: 99%

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Chemsensor of NO2 gas based on porphyrin of 5, 10, 15, 20-tetraphenylporphyrin LB films and LS films

Sales

Mansur

2008

Mat. Res.

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The sensitivity of 5, 10, 15, 20-tetraphenylporphyrin (H 2 TPP) to the presence of NO 2 gas in diluted solutions and in Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) films was investigated by UV-visible spectroscopy. The shift of Soret and Q bands were analyzed and the energies involved were calculated. The exposure of LB porphyrin films deposited onto glass slides to NO 2 has performed as an active chemsensor with 7000 ppm gas concentration. Furthermore, the UV-vis dichroism absorption results associated with the Soret bands have given evidence of the tilt angle of the macrocycle related to the substrate. H 2 TPP in LB film was tilted by an angle of 51 ± 5° and in the LS film was tilted by an angle of 36° ± 5° indicating the formation of a preferential organization of the molecular films depending on the deposition method.

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Section: Uv-vis Absorption Spectra Of Solution and Ls Filmmentioning

confidence: 99%

Section: Uv-vis Absorption Spectra Of Solution and Ls Filmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chemsensor of NO2 gas based on porphyrin of 5, 10, 15, 20-tetraphenylporphyrin LB films and LS films

Sales

Mansur

2008

Mat. Res.

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“…Çizelge 1'de her bir sensör sistemi için hesaplanan t 50 ve t 90 değerleri verilmiştir. Gaz difüzyonunu ve bu kinetik etkileşimi açıklamak üzere geliştirilen modellerden biri Elovichian modelidir (Richardson et al, 2005 …”

Section: Porfirin İnce Filmlerin Organik Buhar Ile Etkileşim Mekanizmunclassified

“…Elovichian modelidir (Richardson et al, 2005) Bu nedenle soğurmanın ln(t)'ye bağlı değişimi incelendiğinde etkileşim hakkında bilgi edinilebilir.…”

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Determination of Interaction Mechanism between Porphyrin Thin Film and Organic Vapor

Evyapan¹

2017

jist

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ÖZET: Bu çalışmada Langmuir-Schaefer (LS) ince film üretim tekniği ile 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy)phenyl]-21H,23H-porphine (EHO) porfirin moleküllü ve poly(methyl methacrylate) (PMMA) molekülü kullanılarak çeşitli tabaka sayılarında ince filmler üretildi. Üretilen ince filmlerdeki duyarlı bölgeyi EHO molekülü oluştururken, PMMA tabakası bir çeşit bariyer olarak kullanıldı. PMMA molekülü polimer yapısından dolayı ince film olarak transfer edildiğinde birbirine çok yakın bir düzende film oluşturmaktadır. Dolayısıyla PMMA tabakasının gaz moleküllerinin EHO tabakalarına ulaşmasını engelleyen bir bariyer özelliği göstermesi beklenir. Beklenen bu bariyer etkisini incelemek amacıyla asetik asit buharı kullanılarak ince film buhar etkileşimleri UVgörünür spektroskopisiyle kaydedildi. EHO ince filmler çok tabakalı üretilerek PMMA tabakasının konumuna bağlı olarak sensör tepkileri ölçüldü. Bu sayede ince film ile gaz molekülleri arasında gerçekleştiği düşünülen farklı etkileşim aşamaları aydınlatılmaya çalışıldı. PMMA tabakasının farklı konumlarının tepki süresini, hızını ve şiddetini etkilediği görüldü. Teorik olarak varsayıldığı gibi gaz moleküllerinin öncelikle ince film yüzeyi ile etkileştikleri daha sonra filmin içerisine girerek difüzyon etkileşiminin gerçekleştiği deneysel sonuçlar ile kanıtlandı.Anahtar kelimeler: Langmuir-Schaefer, organik sensör, porfirin, pmma ABSTRACT: Langmuir-Schaefer (LS) films of a free base porphyrin 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy) phenyl]-21H,23H-porphine (EHO) are used in conjunction with a poly(methyl methacrylate) PMMA molecule deposited as a various layer configuration thin films. EHO is the active sensing layer and PMMA is a barrier layer for gas molecules. PMMA molecules stick each other when they transferred on a solid substrate so they can stop vapor molecules before they reach to EHO layers. In order to investigate the gas sensing behaviors acetic acid was chosen for analyte vapor and UV-visible spectrometer was used for sensing system. The layer order of multilayered LS films was varied in order to investigate the sensing characteristics and vapor dynamics. It was observed that the place of PMMA layer effects the response time, speed and intensity. As it is expected from the theoretical studies, the interaction between thin film and vapor molecules starts from the surface of thin film and then vapor molecules starts to penetrate into film structure. The experimental results obtained from this study prove this dynamic diffusion effect between thin film and vapor molecules. Thus the interaction kinetics between thin film molecules and vapor molecules were demonstrated using the barrier layer affect.

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Influence of atomic force microscopy acquisition parameters on thin film roughness analysis

Hristu

Stanciu

Çapan

et al. 2012

Microscopy Res & Technique

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A reliable procedure for measuring parameters connected to surface roughness is needed to compare the gas sensing properties of various thin films or the effect of different fabrication procedures on the surface roughness and the sensing properties. In this article, we propose to investigate how the acquisition parameters specific to atomic force microscopy investigations such as pixel size, scan area and scan speed influence the roughness parameters, namely root mean square and surface area ratio, commonly used for characterizing the gas sensing properties of porphyrins and other materials.

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Development and optimization of porphyrin gas sensing LB films

Cited by 64 publications

References 12 publications

Chemsensor of NO2 gas based on porphyrin of 5, 10, 15, 20-tetraphenylporphyrin LB films and LS films

Chemsensor of NO2 gas based on porphyrin of 5, 10, 15, 20-tetraphenylporphyrin LB films and LS films

Determination of Interaction Mechanism between Porphyrin Thin Film and Organic Vapor

Influence of atomic force microscopy acquisition parameters on thin film roughness analysis

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