Conductive polymer compsn. used e.g. as photoelectric elements

NOVELTY - A conductimetric or piezoelectric gas sensors comprises: (i) one or more conducting organic polymers; (ii) gas sensitive interrogation means for interrogating a conductimetric or piezoelectric property of the polymer(s), where at least one of the conducting organic polymers is a substituted polythiophene having a substitutent at position-3. USE - Used for sensing gases, vapors, and odors by the response fingerprint the pattern of sensor responses across the array. ADVANTAGE - Impressive range of gases can be detected and identified - either individually or as components as mixtures with good sensitivity. The gas sensors are less affected by humidity, and can employ relatively large electrode gaps. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (a) use of conducting organic polymer for sensing gases using a substituted organic polythiophene having at position-3; (b) the polythiophene comprising repeat oligomer units, in which at least one of the constituent thiophene rings is substituted at position-3; (c) the use of poly(3,3-dihexyl-2,2:5',2-terthiophene) for sensing gases; (d) a multilayer comprising at least two layers of conducting organic polymer, in which the first layer of conducting organic polymer comprises a substituted polythiophene at position-3, and the second layer is deposited onto the first layer; (e) a conducting substituted polythiophene having a substituent at position-3 and PF6- or FeCl4- dopant anions associated with it; (f) a method of manufacturing a gas sensor comprising: (I) providing a solution of the substituted polythiophene polymer, in its non-conducting form, dissolved in a solvent; (II) applying the solution to a substrate; (III) removing the solvent to produce a deposit of the substituted polythiophene polymer in its non-conductive form; and (IV) doping the deposit of substituted polythiophene polymer to produce the conducting form of the polymer.