pH regulated desiccation crack network: a versatile template for Transparent Conducting Sheet fabrication

A novel technique of designing network templates for Transparent Conducting Sheet (TCS) has been achieved by careful modulation of pH of a desiccating colloidal suspension. The pH of aqueous Laponite suspension was changed from 7.8 to 12.7 to obtain vivid changes in the geometry and connectivity of the resultant crack network. Micron sized graphite powder compacted by slow uniform evaporation forms the conducting network on glass after the dry clay is removed completely. The resistance, transmittance, reflectance and figure of Merit of the TCSs have been calibrated as functions of colloidal pH. The electrical and optical properties of the TCSs have been correlated to the topological measure Euler Characteristic and tortuosity of the network. The graphite on glass TCS show selective transmittance at certain pH values. The work demonstrates a cheap versatile option of TCS fabrication that shall find useful applications.