Light-emitting flexible transparent paper based on bacterial cellulose modified with semiconducting polymer MEH:PPV

Abstract

We demonstrated flexible light-emitting transparent bacterial cellulose (BC) paper modified with semiconducting polymer operated by pulse voltage. We prepared thin (∼ 35 μm) transparent BC films modified with luminescent conjugated polymer MEH:PPV with Ag electrodes. It was shown that the photoluminescence (PL) spectrum of BC/MEH:PPV films contains emission contributions from both BC and MEH:PPV components and that the PL intensity of BC and MEH:PPV maxima versus excitation power is sublinear. This indicates that exciton–exciton annihilation occurs in the light-emitting polymer at high excitation power. We found that the dependences of the spike-like electroluminescence (EL) intensity of BC/MEH:PPV films excited by the pulse voltage at different frequencies versus applied pulse bias and pulse frequency are superlinear. We assume that the turn-on and turn-off spikes originate from the recombination of charges accumulated in the bulk of the semiconducting polymer (bulk de-trapping) during the voltage pulse. The results demonstrate that such composites are prospective for application as flexible, transparent and environmentally friendly light-emitting cellulose-based papers for displays and lighting as well as biosensors.