Study On The Synthesis And Properties Of Metal Tetrafluorophthalocyanines Organic Field-effect Materials

Organic field-effect transistors(OFETs) have attracted a lot of attention due totheir wide application in the area of sensors and large scale integrated circuitscurrently. As the active layer of organic field-effect device, organic semiconductormaterials affect the property of organic field-effect device. Organic field effectmaterials are divided into two classes according to the type of carriers: p-type andn-type materials. N-type OFETs materials are important part of complementary logiccircuit, p-n junction diode and bipolar transistor, but less varieties astrict theirdevelopment and application. Metallophthalocyanines are widely used in field-effectdevices for their macrocyclic conjugated system, good thermal stability andevaporation into film easily. In this paper, F group is introduced to themetallophthalocyanine molecule to decrease the electron density. In this way, wesynthesized2,9,16,23-tetrafluoro metallophthalocyanines which can be used as n-typesemiconductor materials and applied the metal tetrafluorophthalocyanines to organicfield-effect devices.In this paper,4-fluorophthalimide was synthesized using4-nitrophthalimide asraw material by reduction, diazotization and decomposition reaction of diazoniumsalts and the synthetic process was optimized. Under optimum conditions, the totalyield of4-fluorophthalimide was35.2％and the purity was97.2％. The five kind ofmetal tetrafluorophthalocyanines MPcF4(M=Fe、Co、Ni、Cu、Zn) were synthesizedusing4-fluorophthalimide as raw material with carbamide and metal salts by solidstate reaction and the yield were44.7％,68.4％,72.0％,64.6％and54.4％,respectively. The structure of MPcF4were characterized by IR and MALDI-TOF-MS.The properties of UV-vis, fluorescence, thermal, solubility and field-effect devicewere studied and the results showed that the absorption maxima of UV-vis spectrumin DMF was in the range of657~672nm. NiPcF4and CuPcF4displayed aggregationbehavior in UV-vis spectrum. Introduction of F group and increasement ofconcentration and solvent polarity all led to aggregation; The emission maxima offluorescence spectrum in DMF was in the range of598~672nm. With the atomicnumber of central metal was improved, the fluorescence spectra displayed a trend ofred shift; The metal tetrafluorophthalocyanines all possess decomposition temperatureabove270℃indicating that they have a excellent thermal stability; All the metaltetrafluorophthalocyanines can be slightly soluble in pyridine, DMF and DMSO, but do not dissolve in CH2Cl2and acetonitrile; CuPcF4was applied in organic field-effectdevice and displayed n-channel performance, indicating that CuPcF4can be used asn-type semiconductor material in field-effect device. The field-effect mobility is0.014cm2/V·s and the ratio of switched-current is100.