Development of metal sulfide-poly (3-octylthiophene) composite LB multilayers

Langmuir–Blodgett (LB) technique has been used to deposit composite multilayers of poly(3-octylthiophene) with cadmium arachidate (POT-CdA), zinc arachidate (POT-ZnA) and copper arachidate (POT-CuA). These composite multilayers were used as precursors to develop the respective semiconducting CdS, ZnS and Cu2S nanoclusters in the POT-arachidic acid (POT-AA) matrix. The formation of sulphide nanoclusters in the multilayer was determined by FTIR and UV-Vis spectroscopy. X-ray reflectivity measurements showed a drastic reduction in the layered structural order on sulphide formation. Single layer LED structures were fabricated using POT-CdA, CdS-POT-AA and ZnS-POT-AA composites as active layers. The Electoluminescence peaks from these structures are attributed to POT and nanoclusters of CdS and ZnS, respectively. The electroluminescent devices with nanoclusters containing emitter layers exhibited low turn-on voltage ∼5 V. Blue electroluminescence was observed at room temperature from FTO/ZnS-POT-AA/Al devices.