Preparation of ZnO/NiO-loaded flexible cellulose nanofiber film electrodes and their application to dye-sensitized solar cells

Abstract

Since flexible solar cells are demanded portable purposes, materials are requested to be light and soft. Hence the present work focused on the preparation of metal oxide-based flexible dye-sensitized solar cells (DSSCs) using sustainable, eco-friendly TEMPO-oxidized cellulose nanofiber (TOCNF) films as substrates and their performances were compared. When nanorod (NR), nanowire (NW), and nanoparticle (NP) of ZnO or NiO as photovoltaic materials and carbon dot (Cdot) and N719 dye as photosensitizers were used, the coating of ZnONP (50 wt%) incorporated Cdot on ZnONW/Cdot/TOCNF substrate revealed the better photovoltaic conversion efficiency (PCE) (1.34%) and the lower charge transfer resistance property. A NiONP/Cdot-coated NiONW/TOCNF electrode also achieved a good PCE, but the hydrophobic treatment of TOCNF improved the efficiency to be 1.45%. Although the flexible working electrodes for DSSCs were successfully manufactured from a biodegradable and sustainable TOCNF, more effort is still required at least to achieve the performance (4.43%) of conventional non-biodegradable polyethylene terephthalate substrate.