Polyvinyl alcohol/beetroot dye film as light absorbing material in solar cell

Abstract

Solar energy is the green source which can replace unsafe and unclean methods for the generation of electricity. Solar cell is a device that directly converts solar energy into electrical energy through the photovoltaic effect. Solar light absorption and film forming properties are very important requirement for light absorbing material in polymer solar cell. Polymer solar cell has lot of advantages over silicon based solar cell. But the synthesis of solar light absorbing polymers with higher molecular weight requires many synthetic steps and most of the synthesized polymers with higher molecular weights are not solution processable. Therefore, it is very difficult to synthesize solution processable solar light absorbing polymers with high molecular weight. This article reports the development of a novel one-pot synthetic method for the preparation of a light absorbing polymeric material with solution processability. Beetroot dye showed good absorption from the UV-Visible region of the electromagnetic spectrum. Hence it can be used as a light absorbing material in organic solar cell. But it will not form uniform film because of its low molecular weight. In this work, a new material is prepared by mixing beetroot dye with polyvinyl alcohol (PVA). PVA is selected because of its low cost, water solubility, high mechanical strength and good film forming properties. This new material combined the photo physical properties of beetroot dye along with high mechanical strength of polymers. This approach can be extended for the synthesis of large number of semiconducting polymeric materials with solution processability in large scale.