High dielectric constant response of modified copper phthalocyanine

The dielectric properties of copper phthalocyanine-3, 4′, 4″, 4‴-tetrasulfonic acid tetrasodium salt (CuPc_TS) and copper phthalocyanine octacarboxylic acid (CuPc*) were investigated from 20 Hz to 1 MHz with relative humidity from 0 to 75%. A dielectric constant > 106 was found at 1 kHz and 20% humidity for the modified copper phthalocyanines. Humidity increases the dielectric constant, which is attributed to increasing ionization of the peripheral groups as the water enters into the samples.