Preparation And Properties Of Functional Materials Based On Phthalocyanines

With the excellent properties of chemical and thermal stability, low toxicity and especially the strong absorption in the near-IR region, phthalocyanines (Pcs) become a kind of important organic semiconductors which can be used in optical and electronic devices, such as photoreceptors, solar cells, light-emitting diodes and thin-film transistors. The purpose of this work is to develop optical and electrical devices based on Pcs with high-performance, including organic photoreceptor and electrocatalyst. Three parts are included in this work and are described as follows:First, photoconductive oxotitanium phthalocyanine (TiOPc) nanoparticles with an average diameter of 3.6 nm were successfully prepared. These nanoparticles could be well dispersed in organic solvents such as 1,2-dichloroethane to form a stable organic sol. Single-layered photoreceptors (SPLRs) were prepared by coating colloidal solutions containing the C2H4Cl2-stabilized TiOPc nanoparticles and a polycarbonate (PC) resin onto aluminum plates, which exhibited excellent photoconductivity. In this part, the stability of N-TiOPc/DCE organic sol and the charge transport mechanism of these photoreceptors were studied in detail. Several factors which would affect the properties of the N-TiOPc-based SPLR were also investigated.Secondly, a new type of organic electron transport materials (R-TITC), were synthesized by Knoevenagel condensation of truxenone and alkyl cyanoacetates under the irradiation of ultrasound. Ultrasonication improved the yield of the designed molecules by more than one order of magnitude (from less than 3 % to 40 %). The introduction of alkyl cyanoacetate moieties enlarges the conjugated systems and endows R-TITC with large electron affinities (around 3.9 eV) and excellent solubility. The energy offsets between the LUMO of R-TITC and the CB of Pcs facilitate the photo-induced electron transfer from Pcs to R-TITC. Single- and dual-layer positively charged photoreceptors were prepared using R-TITC as the electron transport materials and TiOPc as the charge generation materials, and excellent photosensitivities were obtained.Thirdly,in order to develop excellent electrocatalyst, iron phthalocyanine /platinum catalyst (Pt-FePc/C) was prepared by depositing platinum nanoparticles and FePc on carbon black and used as the cathode catalyst in Direct Methanol Fuel Cell (DMFC). Electrochemical activities for oxygen reduction and methanol tolerance of the prepared catalysts were studied in detail in an acid electrolyte. Compared to the commercial Pt/C catalyst, it was found that the Pt-FePc/C catalyst exhibited a comparable catalytic activity for oxygen reduction reaction (ORR) and much higher methanol tolerance. Besides, the prepared catalyst was found quite sable in an acid electrolyte, which maybe suitable for its application in low-temperature DMFC.