Photonic crystals in biology - NanoTR-VI

Poster Session, Thursday, June 17Humidity Sensing Properties of Copper Phthalocyanine (CuPc) Thin FilmsTheme F686 - N1123Özgen SÖKE 1 , Salih OKUR 1 , Nesli T. YAĞMURCUKARDEŞ 11 Izmir Institute of Technology, Faculty of Science, Department of Physics, Gulbahce Koyu Kampusu, 35430, Urla, Izmir, TurkeyAbstract—This study focuses on the humidity adsorption and desorption kinetics of copper phthalocyanine (CuPc) nanoparticle thin filmprepared by drop cast method, were investigated by quartz crystal microbalance (QCM) technique. Reproducible experimental results show thatCuPc thin films have a great potential for humidity sensing applications at room temperature.Phthalocyanine (Pc) are the subject of a great deal withwide-ranging applications. Copper phthalocyanine (CuPc)thin films have potential applications as surfaceconductivity-based gas sensors, solar cells, dyes, field-effecttransistors , and organic light emitting diodes (OLEDs). Thehumidity adsorption and desorption studies of CuPc is veryimportant for many humidity and gas sensing deviceapplications. In Fig.1 molecular structure of copperphthalocyanine (CuPc) is shown. [1]- [6]F/Hz50-5-10-15-20-25(a)11%22%11%43%22%53%43%53%75%84% 75%84%94% 94%97%-300 1000 2000 3000 4000 5000 6000 7000Time(sec)- F (Hz)100101y = 0.45016 * e^(0.042563x) R= 0.99637y = 1.1664 * e^(0.033464x) R= 0.99547downwardupward0,10 20 40 60 80 100Relative humidity %(RH%)Fig.2 (a and b) The frequency response of Copper phthalocyanine (CuPc)thin films covered QCM adsorption–desorption process at fixed pointrelative humidity conditions between 11% and 97% RH.(b)Fig.1 Structure of Copper Phthalocyanine (CuPc)50%11 RH%11 RHQuartz crystal microbalance (QCM) is a technique that wasused to analyze the change in the resonant frequency. Thisresonant frequency is sensitive to mass changes of thecrystal. In our study, we used QCM with the model ofCHI400A Series from CH, after exposure of the crystalmass loading of water molecules at different humidityenvironments e.g. at 11%, 22%, 43%, 55%, 75%, 84%,94%, 97% relative humidity (RH). [1]- [6]The mass change (Δm) from the measured frequency change(Δf) is calculating to use Saurbey Equation ;22 f0mf A (1)where f 0 is the resonant frequency of the QCM crystal, ρ isthe density of the crystal, μ is the shear modulus of quartzand A is the area of the gold disk on the crystal.CuPc molecules (99% Purity) were solved in toluene with1mg/ml concentration and 5μl of solution were coated ontosurface of QCM by drop-casting method. After evaporationof toluene, thicknesses of CuPc film was measured as300nm with Dektak 150 profilometer of Veeco.Fig.2 (a) shows the frequency response of copperphthalocyanine (CuPc) film when the relative humidityincreased and decreased between 11% and 97% RH for anequal time(400sec) intervals and (b) show how the quartzcrystal microbalance (QCM) frequency changes withincreasing and decreasing RH values.F/Hz-5-10-15-20-2522%43%53%75%84%94%97%-300 200 400 600 800 1000120014001600Time(sec)Fig.3 Comparison of frequency shifts between 11% and 97% RH.Fig.3 shows the comparison of QCM frequency shifts for11%, 22%, 43%, 55%, 75%, 84%, 94%, 97% RH values.Our QCM and electrical measurements results show thathumidity sensing properties of Copper Phthalocyanine(CuPc) is very sensitive to humidty changes and reversibleadsorption/desorption behavior which is an indicative of agood humidity sensor even at room temprature.*Corresponding author: salihokur@iyte.edu.tr[1] S. Okur, M. Kus, F. Özel, V. Aybek, M. Yilmaz, Talanta, 81;1-2; 2010;248.[2] F.Young, M. Shtein, S.R. Forrest, Nature Mater.4,37,(2005)[3] Caronna, T.; Colleoni, C.; Dotti, S.; Fontana, F.; Rosace, G.J.Photochem. Photobiol., A, 184, 135 (2006)[4] Z. Bao, A. J. Lovinger, and A. Dodabaladur, Appl. Phys. Lett. 69, 3066(1996).[5]Yamashita M, Inui F, Irokawa K, Morinaga A, Tako T, Mito A,ApplSurf Sci, 130, 883 (1998).[6] A. Schmidt, L.K. Chau, A. Back, N.R. Armstrong, C.C. Leznoff, B.P.Lewer (Eds.), Phthalocyanines, Properties and Applications, New York:VCH, 1996. M6th Nanoscience and Nanotechnology Conference, zmir, 2010 697