A coating of ZrO2 nanoparticles on an indium tin oxide (ITO) substrate in an alcohol and acetic acid solution forms voids that can be used to tune the effective dielectric constant of mixing layers. After tuning to be between the dielectric constant of ITO (2.5–2.0) and air (~1), the light transmission was enhanced by about eight times. A ZrO2 nanoparticle layer with high light transmission was thus fabricated for a natural pigment-sensitized solar cell. In order to set up an environmentally friendly dye-sensitized solar cell, a water-based electrolyte was used. The efficiency of the green part of Codiaeum varie pigment on the ZrO2 nanoparticle layer was 0.688%. Copyright © 2013 John Wiley & Sons, Ltd.