Upon returning to Corpus Christi College, Cambridge, after a year spent in Japan studying the nonlinear optical properties of poly(arylenevinylene) polymers, he played a central role in the February 1989 discovery of conjugated polymer electroluminescence, suggesting the experiment that led to Jeremy Henley Burroughes' first observation of light emission. Together with Jeremy Burroughes he undertook the initial characterisation of the basic properties of poly(p-phenylenevinylene) light emitting diodes, demonstrating that the light emission phenomenon was injection electroluminescence and that the frequency response was sufficiently fast to permit video display applications. Recognizing the importance of their discovery Bradley and Burroughes decided that it should be patented and together with Richard Friend filed a GB patent (PCT/GB90.00584) with first claim:An electroluminescent device comprising a semiconductor layer in the form of a thin dense polymer film comprising at least one conjugated polymer;a first contact layer which is selected so that on application of an electric field to said device charge carriers of a first type are injected into the semiconductor layer; and a second contact layer which is selected so that on application of an electric field to said device charge carriers of a second type are injected into the semiconductor layers, wherein the polymer film of the semiconductor layer has sufficiently low concentration of extrinsic charge carriers that on applying an electric field between the first and second contact layers across the semiconductor layer as to render the second contact layer positive relative to the first contact layer charge carriers of said first and second types are injected into the semiconductor layer and combine to form in the conjugated polymer charge carrier pairs which decay radiatively so that radiation is emitted from the conjugated polymer.
