Dual Application of Waste Grape Skin for Photosensitizers and Counter Electrodes of Dye-Sensitized Solar Cells

Abstract

Dye-sensitized solar cells (DSSCs), a powerful system to convert solar energy into electrical energy, suffer from the high cost of the Pt counter electrode and photosensitizer. In this study, the dual application of waste grape skin is realized by employing the grape skin and its extract as the carbon source of the carbon-based counter electrode and photosensitizer, respectively. The ultraviolet–visible absorption and Fourier transform infrared spectroscopy verify the strong binding between the dye molecules (anthocyanins) in the extract and the TiO2 nanostructure on the photoanode, contributing to a high open-circuit voltage (VOC) value of 0.48 V for the assembled DSSC device. Moreover, the waste grape skin was subjected to pyrolysis and KOH activation and the resultant KOH-activated grape skin-derived carbon (KA-GSDC) possesses a large surface area (620.79 m2 g−1) and hierarchical porous structure, leading to a high short circuit current density (JSC) value of 1.52 mA cm−2. Additionally, the electrochemical impedance spectroscopy reveals the efficient electron transfer between the electrocatalyst and the redox couples and the slow recombination of electrolytic cations and the photo-induced electrons in the conduction band of TiO2. These merits endow the DSSC with a high photovoltaic efficiency of 0.48%, which is 33% higher than that of a common Pt-based DSSC (0.36%). The efficiency is also competitive, compared with some congeneric DSSCs based on other natural dyes and Pt counter electrode. The result confirms the feasibility of achieving the high-value application of waste grape skin in DSSCs.

Experimental and Computational Studies on Bio-Inspired Flavylium Salts as Sensitizers for Dye-Sensitized Solar Cells

“…Natural dyes, mostly from one of the three main families: chlorophylls, betalains, and anthocyanins, have been the subject of several studies that showed them as promising efficient photosensitizers [ 12 , 13 , 14 , 15 ].…”

Pt-Modified Interfacial Engineering for Enhanced Photocatalytic Performance of 3D Ordered Macroporous TiO2

“…To increase the solar energy utilization and quantum efficiency of TiO 2 , researchers usually modified TiO 2 through tuning its morphology and microstructure to broaden its application areas. In terms of adjusting microstructure, doping [7,8], heterogenization [9,10], photosensitization [11][12][13] and loading [14][15][16][17][18] are the common ways to extend the absorption band and promote the separation of photogenerated carriers in TiO 2 . Among these strategies, metal nanoparticles loading is a common and effective method for improving TiO 2 photocatalysts.…”