Abstract
Dielectric/metal/dielectric (DMD) transparent electrodes emerged as a compelling alternative to the widely used indium-tin-oxide (ITO) for solar cells and optoelectronic devices. DMD electrodes are especially attractive for flexible substrates, as, in contrast to ITO, they retain their low electrical resistance upon substrate bending and they do not require deposition at elevated temperatures. In a DMD, the choice of the dielectric is mainly dictated by the device architecture. Owing to its high work function, MoO3 is a commonly used hole-selective dielectric layer. The present work investigates MoOx/metal/MoOx (with 2 < x < 3) DMD electrodes, with Ag and Au as metals, fabricated by direct current, magnetron sputtering, at industry-relevant, high deposition rates. This was possible with a properly engineered MoOx target, providing high electrical conductivity and compactness. The sputtered electrodes on polyethylene terephthalate (PET) substrates show higher figure-of-merit than similar, evaporated electrodes in the literature. It is shown that the DMD electrodes with amorphous MoOx layers have low stability in water, but they are stable to other solvents, such as toluene, dimethylsulfoxide (DMSO), dimethylformamide (DMF), chlorobenzene or chloroform, allowing their implementation in devices like organic light-emitting diodes or perovskite solar cells. Further, it is shown that the electrodes show dramatically enhanced mechanical stability compared to ITO, when subjected to tensile bending tests.
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Acknowledgement
TD, CL, EF and JW acknowledge financial support through the project NEXT-FOIL (Next generation conductive solar foil for flexible photovoltaics) under the umbrella of SOLAR-ERA.NET Cofund (FFG, SFOE). GL thanks Prof. N. Koch (Humboldt Universität zu Berlin) for granting access to the photoemission instrumentation. GL and ELK acknowledge the financial support of DFG (Projektnummer 182,087,777—SFB 951) and the HySPRINT Innovation Lab at Helmholtz-Zentrum Berlin (through the framework of the Joint Lab GEN_FAB).
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Goetz, S., Wibowo, R.A., Bauch, M. et al. Fast sputter deposition of MoOx/metal/MoOx transparent electrodes on glass and PET substrates. J Mater Sci 56, 9047–9064 (2021). https://doi.org/10.1007/s10853-021-05839-9
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DOI: https://doi.org/10.1007/s10853-021-05839-9