Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV22)
DOI: https://doi.org/10.29363/nanoge.hopv.2022.122
Publication date: 20th April 2022
Metal grid electrodes based on the low-cost metal copper (Cu) and fabricated by the rapid fabrication method of microcontact printing using an alkyl thiol monolayer resist, show performance comparable to indium-tin oxide (ITO) coated glass.[1] However, Cu reacts spontaneously with O2 which undermines the long-term stability of the electrode in air. In order to overcome this limitation we show that a 2.3 nm layer of tin (Sn) buried ~2 nm below the Cu surface dramatically improves the stability of the underlying Cu by hindering oxidation in air. Arrhenius analysis shows that the activation energy for the oxidation of Cu increased from 134 ± 20 to 157 ± 18 kJ mol-1 K-1. Burying the Sn below ~ 2 nm thick Cu overlayer also enables the a patterned monolayer of alkyl thiol resist to be microcontact printed onto the metal film. Following wet etching using the low toxicity etchant ammonium persulfate, high quality grid electrodes are realised. These electrodes have a transparency of ≥ 85% over the range of wavelength 400 to 1100 nm and a sheet resistance of 10.3 Ω/sq making them suitable as the transparent electrode in organic photovoltaics. The performance of efficient organic photovoltaic devices using this electrode in place of ITO glass will be presented.
Saudi Arabian Cultural Bureau (SACB).