Preparation and characterization of dye sensitized solar cells based on ZnO doped with Er and sensitized by natural dyes

Abstract

In order to manage and decrease the environmental impact caused by energy consumption and production, more sustainable sources are needed. Solar cells helps us harvest and use solar power, an inexhaustible source of energy, that is the largest and cleanest that humans have access to. Dye sensitized solar cells or DSSC have become increasingly popular due to their low cost, simple production, no toxicity, and suitable light harvesting properties therefore is being the object of research to find suitable materials and their combinations in order to harness solar energy more efficiently. In this work, DSSCs were prepared using Zinc-oxide (ZnO) doped with rare-earth ion Er (erbium) nanoparticles, at four different concentrations, Zn1−xErxO (0, 1.25, 2.50,5 at.%), as semiconducting layers, and sensitized with two different natural dyes extracted from raspberries (Rubus idaeus) that has an anthocyanin based chemical estructure, and curcumin (Curcuma Longa). I-V (current-voltage) analyses under 1 sun illumination were performed in all DSSCs in order to find the best combination and finally a circit model equivalent was obtain for all the DSSC. The highest efficiency obtained was η=0.00644% with a Isc=56.209 μA, Voc=338 mV and FF=33.908% from the anthocyanin dye ZnO:Er 1.25 at.% cell, representing an increment of 218 % from the anthocyanin ZnO:Er 0 at.% cell with an efficiency of η=0.00202%. The highest efficiency for the curcumin dye was η=0.00216% with a Isc=30.676 μA, Voc=238 mV and FF=29.619% from the ZnO:Er 1.25 at.% cell, representing and increment of 13.5% from the ZnO:Er 0 at.% cell with an efficiency of η=0.00191%. Given the increments in efficiency, the doping of ZnO nanoparticles with Er in 1.25 at.% enhances the overall performance of the cell in both dyes and the natural dye that had the overall highest efficiency, Isc, Voc and FF was the anthocyanin based. The circuit equivalent model for all DSSC follow the experimental behavior with less than 5% error for all the electrical parameters.