Electrodeposited Silver Nanowire Transparent Conducting Electrodes for Thin-Film Solar Cells

Silver nanowire (AgNW) networks have demonstrated high optical and electrical properties, even better than those of indium tin oxide thin films, and are expected to be a next-generation transparent conducting electrode (TCE). Enhanced electrical and optical properties are achieved when the diameter of the AgNWs in the network is fairly small, that is, typically less than 30 nm. However, when AgNWs with such small diameters are used in the network, stability issues arise. One method to resolve the stability issues is to increase the diameter of the AgNWs, but the use of AgNWs with large diameters has the disadvantage of causing a rough surface morphology. In this work, we resolve all of the aforementioned issues with AgNW TCEs by the electrodeposition of Ag onto as-spin-coated thin AgNW TCEs. The electrodeposition of Ag offers many advantages, including the precise adjustment of the AgNW diameter and wire-to-wire welding to improve the junction conductance while minimizing the increase in protrusion height because of the overlap of AgNWs upon increasing the diameter. In addition, Ag electrodeposition on AgNW TCEs can provide higher conductance than that of as-spin-coated AgNW TCEs at the same transparency because of the reduced junction resistance, which generates a superior figure of merit. We applied the electrodeposited (ED) AgNW network to a Cu­(In,Ga)­Se2 thin-film solar cell and compared the device performance to a device with a standard sputtered transparent conducting oxide (TCO). The cell fabricated by the electrodeposition method showed nearly equal performance to that of a cell with the sputtered TCO. We expect that ED AgNW networks can be used as high-performance and robust TCEs for various optoelectronic applications

Hierarchical Silver Network Transparent Conducting Electrodes for Thin-Film Solar Cells

Flexible metal network transparent conducting electrodes (TCEs) are expected to be the most promising candidates to replace indium tin oxide (ITO) due to their excellent electro-optical performance and mechanical flexibility. However, to successfully replace ITO with the metal network TCEs, more studies on their suitability for integration with real devices are needed. In this study, we developed a hierarchical silver network simultaneously meeting the requirements of (i) low sheet resistance, (ii) high optical transmittance, (iii) excellent mechanical flexibility, and (iv) good integration into a thin-film solar cell. The hierarchical silver network consists of a silver micromesh as the main framework and silver nanowires as the secondary framework. The hierarchical network provides a figure of merit similar to that of the individual micromesh and much higher than those of silver nanowires and ITO. When applied to Cu­(In, Ga)­Se2 thin-film solar cells, the hierarchical network achieved better device performance than the micromesh. In the hierarchical network, the micromesh enables low sheet resistance and the silver nanowires enable excellent integration with the device while maintaining high optical transmittance. Thus, considering the aforementioned requirements, the hierarchical network could be one of the best candidates as a TCE for Cu­(In, Ga)­Se2 thin-film solar cells

Hierarchical Silver Network Transparent Conducting Electrodes for Thin-Film Solar Cells

Flexible metal network transparent conducting electrodes (TCEs) are expected to be the most promising candidates to replace indium tin oxide (ITO) due to their excellent electro-optical performance and mechanical flexibility. However, to successfully replace ITO with the metal network TCEs, more studies on their suitability for integration with real devices are needed. In this study, we developed a hierarchical silver network simultaneously meeting the requirements of (i) low sheet resistance, (ii) high optical transmittance, (iii) excellent mechanical flexibility, and (iv) good integration into a thin-film solar cell. The hierarchical silver network consists of a silver micromesh as the main framework and silver nanowires as the secondary framework. The hierarchical network provides a figure of merit similar to that of the individual micromesh and much higher than those of silver nanowires and ITO. When applied to Cu­(In, Ga)­Se2 thin-film solar cells, the hierarchical network achieved better device performance than the micromesh. In the hierarchical network, the micromesh enables low sheet resistance and the silver nanowires enable excellent integration with the device while maintaining high optical transmittance. Thus, considering the aforementioned requirements, the hierarchical network could be one of the best candidates as a TCE for Cu­(In, Ga)­Se2 thin-film solar cells