Reversible Electrochromism of Copper Phthalocyanine Thin Film

Abstract

The electrochromism of copper phthalocyanine thin films was examined in detail under various conditions. The application of a positive voltage to copper phthalocyanine thin film exhibited two oxidation peaks in the range from 0 to 1.4 V. Although the color of the film changed from sky blue to pale gray upon scanning the voltage in this region, irreversible electrochromism was observed, leading to a deterioration of the film. The two oxidation peaks were concluded to represent two types of appearances of one reaction with different overpotentials caused by the structure of the crystal grains of the film. Control of the scan range to admit only the first oxidation peak provided a reversible electrochromism between sky blue and bluish purple. Electrolyte anions are also of great importance to accomplish reversible electrochromism. Thus, the anions should be stable for the application of a positive voltage, and their Stokes radii should be neither too large nor too small in order to achieve reversible electrochromism. Rather small anions provide almost Nernstian cyclic voltammograms and the quick color change.

Layer-by-layer deposition films of copper phthalocyanine derivative; their photoelectrochemical properties and application to solution-processed thin-film organic solar cells

“…This technique is based on electrostatic adsorption of oppositely charged materials such as polycations, polyanions, and charged small molecules. Until now, many studies have been carried out on the fabrication and characterization of ultrathin films of Pc derivatives using this technique [16][17][18][19][20][21][22][23][24]. However, only a few studies dealing with thinfilm organic solar cells have been reported [24].…”

Construction of a ‘Sequential Potential Field’ by [Cu(pc)]/[Zn(pc)] double-layered Thin Film: Application to Electrochromic and Electroluminescent Devices

“…In the previous study [18], it is revealed that this reversible process can be obtained by the wellcontrolled scan range, which controls the movement of the electrolyte anions for charge compensation. If the positive voltages are applied from 0 to 1.4 V, then [Ni(pc)] thin film exhibits two oxidation peaks and the colour of the film changes from sky blue to pale grey.…”

“…[M(pc)] thin films (~40 nm in thickness) were prepared by the method described in an earlier publication [18]. Films were deposited onto indiumtin oxide (ITO) glass (10 Ω/ᮀ) previously cleaned by washing ultrasonically with dichloromethane and then 2-propanol.…”

“…Electrochemical measurements of the thin films were carried out at room temperature in 0.1 mol dm -3 NaNO 3 aqueous solutions as described earlier [18]. The working electrode was the ITO glass covered with the phthalocyanine thin film prepared by vapour deposition.…”

Photoluminescence characterization of polythiophene films incorporated with highly functional molecules such as metallophthalocyanine

“…PcMs complexes exhibit strong optical absorption in the visible range and favorable electrical properties. [7][8][9] PcMs are highly conjugated p-electron structures and are attractive synthetic materials because the diversity of their structures and unique optical and electrical properties lead to wide range of potential applications such as photovoltaic cells, [10][11][12][13] nonlinear optics, 14 photoconducting materials, 15 electrochromic substances, 16,17 Langmuir-Blodgett films, 18 and carrier generation materials in the near infrared region. 19 The present study focuses on the photoluminescence (PL) properties of PcMs doped in PT to investigate how PcMs affect the emission properties of PT and what the cause of the changes in the PL properties is when PcM molecules are injected into the polymer matrix through a doping process.…”