The dielectric function of some phthalocyanine compounds (ZnPc,H2Pc,CuPc,and FePc) were investigated by analyzing the measured capacitance and loss tangent data.The real part of the dielectric constant,ε1,varies strongly with frequency and temperature.The frequency dependence was expressed as:ε1 =Aωn,where the index,n,assumes negative values (n ＜ 0).In addition,the imaginary part of the dielectric constant,ε2,is also frequency and temperature dependent.Data analysis confirmed that ε2 =Bωm with values of m less than zero.At low frequencies and all temperatures,a strong dependence is observed,while at higher frequencies,a moderate dependence is obvious especially for the Au-electrode sample.Qualitatively,the type of electrode material had little effect on the behavior of the dielectric constant but did affect its value.Analysis of the AC conductivity dependence on frequency at different temperatures indicated that the correlated barrier hopping (CBH) model is the most suitable mechanism for the AC conduction behavior.Maximum barrier height,W,has been estimated for ZnPc with different electrode materials (Au and Al),and had values between 0.10 and 0.9 eV.For both electrode types,the maximum barrier height has strong frequency dependence at high frequency and low temperatures.The relaxation time,τ,for ZnPc and FePc films increases with decreasing frequency.The activation energy was derived from the slopes of τ versus 1/T curves.At low temperatures,an activation energy value of about 0.01 eV and 0.04 eV was estimated for ZnPc and FePc,respectively.The low values of activation energy suggest that the hopping of charge carriers between localized states is the dominant mechanism.
参考文献
| [1] | Honeybourne C L,Ewen R J.The enhancement ofdark D.C.conductivity by gas adsorption on thin films of macrocyclic copper complexes.J Phys Chem Solids,1983,44 (8):833 |
| [2] | Wilson A Collins R A.Electrical characteristics of planar phthalocyanine thin film gas sensors.Sensors and Actuators,1987,12(4):389.Also,Collins R A,Ellis M K,Jones T A.Sensitivity of lead phthalocyanine thin films to ammonia and nitrogen dioxide.Chemtronics,1991,5:93 |
| [3] | Wilson A Collins R A.Electrical characteristics of planar phthalocyanine thin film gas sensors.Sensors and Actuators,1987,12(4):389.Also,Collins R A,Ellis M K,Jones T A.Sensitivity of lead phthalocyanine thin films to ammonia and nitrogen dioxide.Chemtronics,1991,5:93 |
| [4] | Van Ewyk R L,Chadwick A V,Wright J D.Effects of oxygen,nitrogen dioxide and trifluoroborane on photoconductivity of perylene and phthalocyanine single crystals.J Chem Soc,Faraday Trans,1981,77(1):73 |
| [5] | Huo L,Cao L,Li X,et al.Study of ferric oxide nanoparticles-tris(2,4-di-t-amylphenoxy)-(8-quinolinolyl) copper phthalocyanine.Thin Solid Films,2002,365(1):129 |
| [6] | Ho K C,Tsou Y H.Chemiresistor-type NO gas sensor based on nickel phthalocyanine thin films.Sensors and Actuators B,2001,77(1/2):253 |
| [7] | Rellaa R,Rizzob A,Licciullic A,et al.Tests in controlled atmosphere on new optical gas sensing layers based on TiO2/metalphthalocyanines hybrid systems.Mater Sci Eng C,2002,22(2):439 |
| [8] | Zhang Z L,Jiang X Y,Zhu W Q,et al.A white organic light emitting diode with improved stability.J Phys D:Appl Phys,2001,34(20):308 |
| [9] | Henari F Z.Optical switching in organometallic phthaloeyanine.J Opt A:Pure Appl Opt,2001,3(3):188 |
| [10] | Kerp H R,Van Faassen E E.Effects of oxygen on exciton transport in zinc phthalocyanine layers.Chem Phys Lett,2000,332(1/2):5 |
| [11] | Pfeiffer M,Beyer A,Pl(o)nnigs B,et al.Controlled p-doping of pigment layers by cosublimation:basic mechanisms and implications for their use in photovoltaic cells.Solar Energy Mat Solar Cells,2000,63(1):83 |
| [12] | Gao W,Kahn A.Electronic structure and current injection in zinc phthalocyanine doped with tetrafluorotetracyanoquinodimethane:interface versus bulk effects.Org Electron,2002,3(2):53 |
| [13] | Sch(o)llhorn B,Germain J P,Pauly A,et al.Influence of peripheral electron-withdrawing substituents on the conductivity of zinc phthalocyanine in the presence of gases.Part 1:reducing gases.Thin Solid Films,1998,326(1/2):245 |
| [14] | Germain J P,Pauly A,Maleysson C,et al.Influence of peripheral electron-withdrawing substituents on the conductivity of zinc phthalocyanine in the presence of gases.Part 2:oxidizing gases.Thin Solid Films,1998,333(1/2):235 |
| [15] | Drechsles U,Pfaff M,Hanack M.Synthesis of novel functionalised zinc phthalocyanines applicable in photodynamic therapy.Europ J Organic Chem,1999,(12):3441 |
| [16] | Gao L,Qian X,Zhang L,et al.Tetra-trifluoroethoxyl zinc phthalocyanine:potential photosensitizer for use in the photodynamic therapy of cancer.J Photochemistry and Photobiology,2001,65(1):35 |
| [17] | Fadel M,Kassab K,Fadeel D A.Zinc phthalocyanine-loaded PLGA biodegradable nanoparticles for photodynamic therapy in tumor-beating mice.Lasers Med Sci,2010,25(2):283 |
| [18] | Bowler C J,Gould R D.A sequential masking system for the deposition ofmultilayer thin film structures.J Vacuum Sci Technol A,1987,5(1):114 |
| [19] | Hassan A K,Gould R D.The effects of exposure to oxygen and annealing on the conductivity of copper phthalocyanine thin films.J Phys D:Condensed Matter,1989,1(37):6679 |
| [20] | Shafai T S,Gould R D.Transport properties in lead phthalocyanine thin films for use in FET structures.Int J Electronics,1990,69(1):3 |
| [21] | Gould R D.Dependence of the mobility and trap concentration in evaporated copper phthalocyanine thin films on background pressure and evaporation rate.J Phys D:Appl Phys,1986,19(9):1785 |
| [22] | Gould R D.D.C.Electrical measurements on evaporated thin films of copper phthalocyanine.Thin Solid Films,1985,125(1/2):63 |
| [23] | Zeyada H M,El-Nahass M M.Electrical properties and dielectric relaxation of thermally evaporated zinc phthalocyanine thin films.Appl Surf Sci,2008,254 (6):1852 |
| [24] | Nalwa H S,Vazudevan P.Dielectric properties of cobalt phthalocyanine.J Mat Sci Lett,1983,2(1):22 |
| [25] | Fan F R,Falkner L R.Photovoltaic effects of metalfree and zinc phthalocyanines Ⅱ:properties of illuminated thin-film cells.J Chem Phys,1978,69(7):3341 |
| [26] | Ahmad A,Collins R H.Schottky barrier and electrical transport in oxygen-doped triclinic lead phthalocyanine films.Phys Status Solidi A,1991,126(2):411 |
| [27] | Shihub S 1,Gould R D.Frequency dependence of electrical conduction parameters in evaporated thin films ofcobalt phthalocyanine.Thin Solid Films,1995,254(1/2):187 |
| [28] | Kumar M P,Sankarappa T,Kumar S.AC conductivity studies in rare earth ions doped vanadotellurite glasses.J Alloys Compd,2008,464(1/2):393 |
| [29] | Kumar R S,Hariharan K.AC conductivity and electrical relaxation studies on 10CuI-60AgI-30V2O5 glasses.Mat Chem Phys,1999,60(1):28 |
| [30] | Bergo P,Pontuschka W M,Prison J M,et al.Dielectric properties of barium phosphate glasses doped with transition metal oxides.J Non-Cryst Solids,2004,348:84 |
| [31] | Sanghi S,Rani S,Agarwal A,et al.Li+ ion constriction in presence of Bi2O3 and ac conductivity in Li2O·P2O5·Bi2O3 glasses.Physica B,2009,404(14/15):1969 |
| [32] | Amar N M,Saleh A M,Gould R D.Influence of temperature and frequency on the electrical parameters of thermally evaporated metal-free phthalocyanine H2Pc thin films.Appl Phys A,2003,76(1):77 |
| [33] | Orti E,Brades J L.Electronic structure ofmetal-free phthalocyanine:a valence effective Hamiltonian theoretical study.J Chem Phys,1988,89(2):1009 |
| [34] | Abu-Hilal A O,Saleh A M,Gould R D.Effect of electrode material on AC electrical conductivity of organic zinc phthalocyanine semiconducting thin films.Mat Chem Phys,2005,94(1):165 |
| [35] | Saleh A M,Gould R D,Hassan A K.Dependence of AC electrical parameters on frequency and temperature in zinc phthalocyanine thin films.Phys Status Solidi A,1993,139(2):379 |
| [36] | Khan G A,Hogarth C A.Optical absorption spectra of evaporated V2O5 and co-evaporated V2Os/B2O3 thin films.J Mat Sci,1991,26(2):412 |
| [37] | Elliott S R.A theory of A.C.conduction in chalcogenide glasses.Philos Magz,1977,36(6):129 1.Also in,Elliott S R.Temperature dependence of A.C.conductivity of chalcogenide glasses.Philos Magz,1978,37(5):553 |
| [38] | Elliott S R.A theory of A.C.conduction in chalcogenide glasses.Philos Magz,1977,36(6):129 1.Also in,Elliott S R.Temperature dependence of A.C.conductivity of chalcogenide glasses.Philos Magz,1978,37(5):553 |
| [39] | Kumar S,Husain M,Zulfequar M.Dielectric relaxation in the glassy a-Se-Te-Ga system.Physica B,2007,387(1/2):400 |
| [40] | Zeyada H M,El-Nahass M M,El-Zawawi I K,et al,Structural and optical properties of thermally evaporated 2-(2,3-dihydro1,5-dimethyl-3-oxo-2-phenyl-l H-pyrazol-4-ylimino)-2-(4-nitrophenyl)acetonitrile thin films.J Phys Chem Solids,2010,71(6):867 |
| [41] | Long A R.Frequency-dependent loss in amorphous semiconductors.Adv Phys,1982,31(5):553 |
| [42] | Bekheet A E.AC conductivity and dielectric properties of Ga2S3-Ga2Se3 films.Physica B,2008,403(23/24):4342 |
| [43] | Riad A S,Korayem M T,Abedl-Malik T G.AC conductivity and dielectric measurements of metal-free phthalocyanine thin films dispersed in polycarbonate.Physica B,1999,270(1/2):140 |
| [44] | Senthilarasu S,Sathyamoorthy R,Ascencio J A,et al.Dielectric and AC conduction properties of zinc phthalocyanine (ZnPc) thin films.J Appl Phys,2007,101(3):034111 |
| [45] | Jonscher A K.Alternating current diagnostics of poorly conducting thin films.Thin Solid Films,1976,369(1):1 |
| [46] | Le Moigne J,Even R.Spectroscopic properties and conductivity of thin films of partially reduced metallo-phthalocyanines.J Chem Phys,1985,83(12):6472 |
| [47] | Gould R D,Awan S A.Dielectric properties of AlNx thin films prepared by RF magnetron sputtering of Al using a N2/Ar sputtering gas mixture.Thin Solid Films,2004,469/470:184 |
| [48] | Mahmood F S,Gould R D.A.C.properties of ZnO thin films prepared by r.f.magnetron sputtering.Thin Solid Films,1994,253(1/2):529 |
| [49] | Vidadi Y,Rozenshtein L D,Chistyokov E A.Hopping and band conductivities in organic semiconductors.Sov Phys:Solid State,1969,11(1):173 |
| [50] | Gould R D,Hassan A K.A.C.electrical properties of thermally evaporated thin films of copper phthalocyanine.Thin Solid Films,1993,223(2):334 |
| [51] | Mohsen A K,Saleh A M,Gould R D.Conduction processes and D.C.electrical parameters of thermally evaporated iron phthalocyanine (FePc) thin films with aluminum electrodes.Dirasat (Jordan Univ.Research Journal),2001,28(1):61 |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%