A NEW-TYPE OF IONOPHORE FOR ION-SELECTIVE FIELD-EFFECT TRANSISTORS

A phthalocyanine subunit functionalized with three crown-ether macrocy cles and one paraffinic side chain terminated with a carboxylic group has been used for grafting the surface of the gate insulator of a fiel d-effect transistor. This type of structure has been chosen to favor n onlinear ion complexations as previously demonstrated in solution. The chemical means used to graft and substitute the silica surface are de scribed. The effect of various cations (Na+, K+, Cs+ Ca2+, Ba2+) on th e characterics of the ion-selective field-effect transistor (ISFET) is described. A model previously reported in the literature has been use d to rationalize the results.