Organic thin-film solar cell and organic thin-film solar cell manufacturing method

Abstract

A method is used to produced an organic thin-film solar cell that includes a substrate and an anode, an organic thin-film layer including an organic semiconductor layer, and a cathode layered on top of the substrate. The method includes forming a particle monolayer film that includes a mixture of particles of different average particle sizes on a surface of an original plate for a mold, dry etching using the particle monolayer film as an etching mask to form a recess and protrusion-shaped microstructure, producing a transfer member in which the microstructure is inverted, layering at least the anode and the organic thin-film layer on top of the substrate, transferring the microstructure or the inverted microstructure to a surface of the organic thin-film layer by pressing the mold or the transfer member thereon, and layering the cathode on top of the organic thin-film layer.

What is claimed is: 
     
         1 . A method of manufacturing an organic thin-film solar cell that includes a substrate and an anode, an organic thin-film layer including an organic semiconductor layer, and a cathode layered on top of the substrate, the method comprising the steps of:
 forming a particle monolayer film that includes a mixture of particles of different average particle sizes on a surface of an original plate for a mold;   dry etching using the particle monolayer film as an etching mask to form a recess and protrusion-shaped microstructure that includes a plurality of recesses or protrusions arranged two-dimensionally at random on the surface of the original plate for the mold in order to produce a mold;   producing, as needed, a transfer member in which the recess and protrusion-shaped microstructure is inverted;   layering at least the anode and the organic thin-film layer on top of the substrate;   transferring the microstructure of the mold or the inverted microstructure of the transfer member to a surface of the organic thin-film layer by pressing the mold or the transfer member thereon; and   layering the cathode on top of the organic thin-film layer to form the microstructure or the inverted microstructure in an interface between the organic thin-film layer and the cathode.   
     
     
         2 . The method of manufacturing an organic thin-film solar cell according to  claim 1 ,
 wherein the microstructure is formed such that,   when λ 1  and λ 2  are a shorter wavelength and a longer wavelength, respectively, of wavelengths that produce an absorption edge in a light absorption spectrum of the organic semiconductor layer, and k 1  and k 2  are real parts of propagation constants of surface plasmons that correspond, respectively, to those wavelengths and occur along an interface between the organic semiconductor layer and the cathode, and   when the real part k 1  corresponds to an upper wavenumber limit K 1  in a power spectrum of a height distribution of the microstructure formed in the interface between the cathode and the organic semiconductor layer, and the real part k 2  corresponds to a lower wavenumber limit K 2  in the power spectrum of the height distribution of the microstructure formed in the interface between the cathode and the organic semiconductor layer,   the power spectrum of the height distribution of the microstructure exhibits determinate values between the wavenumber K 1  and the wavenumber K 2 , and an integrated value of a spectral intensity of the power spectrum of the height distribution over a wavenumber range from K 1  to K 2  is equal to at least 50% of an integrated value of the spectral intensity of the power spectrum of the height distribution over all wavenumbers.