Wavelength dependence of capacitance of δ-type MnO2 by light irradiation and suppression of the desorption of interlayer metal complexes by interlayer long-chain alkylammonium ions

Abstract

Two different layered MnO2 thin films with varying layering order of [Co(en)3] and (C12H25)2(CH3)2N ions were prepared, and their capacitances were measured. The top MnO2 layer containing (C12H25)2(CH3)2N ions between the layers inhibited the desorption of the [Co(en)3] complex and exhibited a higher capacitance (287.3 F/g) compared to a thin film with a top MnO2 layer of the [Co(en)3] complex. Furthermore, thin films with a MnO2 layer intercalated with (C12H25)2(CH3)2N ions were irradiated with light at 360, 460, and 560 nm, and their capacitances were measured. As a result, the thin film irradiated at 460 nm demonstrated the highest initial capacitance of 687.6 F/g and the highest cycle stability with a degradation rate of 3.2%.