Thickness control of solution deposited YBCO superconducting films by use of organic polymeric additives

Abstract

We show that the thickness of yttrium-barium-copper-oxide (YBCO) superconducting films grown from trifluoroacetate precursors can be strongly modified using polymeric additives, while deposition conditions by spin or dip coating remain unchanged. A screening of different families of organic additives has been performed, and the best results have been achieved using polymers having an oxygen functionalized backbone. Two different polymeric additives, polyvinyl pyrrolidone (PVP) and poly(ethylene glycol) (PEG), have been more thoroughly investigated, and thermal analysis suggests that PEG is the most promising alternative because the pyrolysis step of the new complex precursors remains sharp and narrow and hence the final homogeneity of the film is preserved. The combination of anhydrous trifluoroacetic acid (TFA) solutions and poly(ethylene-glycol) (PEG 8000 ) as additive can produce an increase of the YBCO film thickness up to 300%, while keeping a fast pyrolysis process and high critical current densities.

A rapid process of YBa2Cu3O7−δthin film fabrication using trifluoroacetate metal–organic deposition with polyethylene glycol additive

“…The TGA curves confirmed the temperature difference of decomposition between pure PEG2000 and solution 30%PEG2000. The decomposition of pure PEG2000 started at 190 • C and was almost finished at 260 • C, while a significant mass loss in solution 30%PEG2000 caused by decomposition started at about 270 • C. Such a decomposition temperature difference between pure PEG and TFA-PEG samples was also observed in the study on PEG8000 addition by Morlens et al [24]. From the TGA curves in figure 9, it could be learnt that some portion of PEG2000 additive remained in the precursor film coated by solution 30%PEG2000 during the decomposition reactions, which could modify the mechanical properties and other characteristics of the precursor film.…”

“…Plasticizers were additive substances to increase the flexibility, workability or distensibility of a material [22]. Moreover, PEG additive had been used by ICMAB [23,24] and other groups [25] to enhance the viscosity of the TFA-MOD precursor solution, and thus increase the film thickness. These studies indicated that PEG was compatible with the TFA-MOD YBCO fabrication, and PEG had beneficial potential to modify the characteristics and decomposition reaction of the precursor films in pyrolysis.…”

Epitaxial superconducting GdBa2Cu3O7−δ /Gd2O3 nanocomposite thin films from advanced low-fluorine solutions

“…This is probably the reason why different ligands (TEA, DEA, PEG, etc.) are sometimes used to improve the quality of the CSD films and the use of propionic acid as solvent 16,43,52,53 . Finally, the use of propionic acid instead of TFA also helps to reduce the water absorption of the solution.…”

High Performance of Superconducting YBa2Cu3O7 Thick Films Prepared by Single-Deposition Inkjet Printing

“…Solutions 2 and 4 with concentrations of 0.5 M lead to an improved liquid distribution after IJP; however, they still display some coffee ring effect and so a more detailed analysis of the deposition process was required. In the case of solution 2, having a relatively low viscosity, we also analyzed the influence of including polymeric additives, such as polyethylene glycol which had previously demonstrated to be useful in increasing film thickness by spin coating . We were able to considerably increase the ink viscosity up to the maximum practical limit of the IJP nozzle (∼20 mPa s); however, huge liquid movements were detected in this case.…”