Formation of a Perylenetetracarboxylic Diimide Network Film by Post Electrochemical Treatment

Abstract

Perylenetetracarboxylic diimide (PDI) derivatives bearing two or four peripheral pyrrole pendants (PDI-nPy, n=2 or 4) are cross-linkable materials by electro/phototreatment. In this paper, we introduce a new posttreatment technique to produce an insoluble film. Unlike the common solution-phase electrochemical deposition, we first spin-coated PDI-nPy on an electrode and then electrotreated the coated surface in a monomer-free electrolyte solution. This method gives the film a smooth surface with no granules, while the common method induces a rough film with a lot of granules. The post electrochemical treatment also provides a merit of higher resolution in a patterning process on a specific metal electrode. As one of the applications, we carried out an electrochromic study on the posttreated PDI-4Py film. It turned purple (lambdamax=590 nm) and sky blue (lambdamax=797 nm) at 0 and -1.9 V vs Ag/Ag+, respectively. We believe this method will broaden the patterning concept with the desired film morphology and resolution using PDI on a specific electrode.

Aggregation of 3,4,9,10-Perylenediimide Radical Anions and Dianions Generated by Reduction with Dithionite in Aqueous Solutions

“…The 3,4,9,10-perylenediimides (PDI) are a class of organic dyes with high thermal and photostability. − The PDI are known as one of the best n-type organic semiconductors, , which makes them very suitable for applications in optoelectronic devices, such as solar cells, − organic field-effect transistors, − and electroluminescent devices. , The remarkable properties of PDI arise from the ease of reduction, which is a common characteristic of the aromatic diimides, including the 1,4,5,8-naphthalenediimides (NDI). − Accordingly, the PDI and NDI can be easily reduced in two steps, generating first radical anions, followed by doubly reduced dianions. − The formation of radical anions by reduction of the NDI in aqueous solution with sodium dithionite has been well reported. , Surprisingly, there is much less information available on the reduction of PDI, in spite of the central role of PDI radical anions in semiconductor devices. Most of the reported studies employed electrochemical − ,− or photochemical reduction in organic solvents. Since most reported electrochemical studies were performed in organic solvents, there is a lack of information about the behavior of PDI reduced species in aqueous solutions.…”

“…20,21 Surprisingly, there is much less information available on the reduction of PDI, in spite of the central role of PDI radical anions in semiconductor devices. Most of the reported studies employed electrochemical [14][15][16][22][23][24][25] or photochemical 26 reduction in organic solvents. Since most reported electrochemical studies were performed in organic solvents, there is a lack of information about the behavior of PDI reduced species in aqueous solutions.…”