Electrochemical and optical devices based on molecule/high-Tc superconductor structures

Through the use of electrochemical and vacuum deposition techniques, molecular materials are combined with high-T_c superconductors in order to fabricate two new classes of hybrid devices. In the first class of devices, electrochemical methods are utilized to deposit polypyrrole onto YBa₂Cu₃O_7-δ structures. With such systems, experiments are conducted which explore electron transfer events which occur between the conductive polymer and the high-T_c superconductor at temperatures both above and below T_c. Here it is found that the transition temperature (T_c) of the superconductor is depressed dramatically when polypyrrole is oxidized to its conductive form and that it returns to a value which is close to the original value upon reduction of the polypyrrole layer to the neutral, nonconductive form. In the second class of devices, the ability of molecular dye layers to affect the optical properties of YBa₂Cu₃O_7-δ photodetectors is demonstrated. By examining changes in the optical and electronic properties of these systems, energy transfer processes which occur between molecules and high-T_c superconductors are explored. Here it is found that dye layers are able to act as antenna for optical radiation at those wavelengths which the dye layer absorbs light most strongly.