Abstract: An electroluminescent device comprises a semiconductor layer (4) in the form of a thin dense polymer film comprising at least one conjugated polymer, a first contact layer (5) in contact with a first surface of the semiconductor layer, and a second contact layer (3) in contact with a second surface of the semiconductor layer. The polymer firm (4) of the semiconductor layer has a sufficiently low concentration of extrinsic charge carriers that on applying an electric field between the first and second contact layers across the semiconductor layer so as to render the second contact layer positive relative to the first contact layer charge carriers are injected into the semiconductor layer and radiation is emitted from the semiconductor layer.

Abstract: Superconducting materials of the (T1,In)-Sr-Ca-Cu-O system-type are modified to raise their critical tempertures by substituting an element M for part of the Tl/In and optionally substituting Y or a rare earth element for some of the Ca.M is a transition metal with valency electrons in d orbitals in its normal state and having accessible tri-and/or tetra-valent states, that is V, Ti, Cr, Zr, Nb, Hf or Ta (which are preferred) Mn, Fe, Co, Ni, Mo, Rh, W, Os, Ir, Re or Ru.