Abstract: Development of photoelectrodes for solar cells offers a strategy to achieve more efficient photon conversion systems. This work develops (TiO2)0.9 + ((ZnO/ZnS):x% rGO)0.1 photoelectrodes with rGO contents of 0.5, 1 and 2%, investigating the influence of the ZnO/ZnS–rGO heterostructure on their structural, electronic, optical, and photovoltaic behavior. The ZnO/ZnS composite was synthesized using the microwave-assisted hydrothermal (MAH) method, and the dye-sensitized solar cell (DSSC) films were deposited by spin-coating. All samples were successfully synthesized, reporting the heterostructure of hexagonal (ZnO) and cubic (ZnS). The sample containing the lowest amount of rGO (0.5%) exhibited the best photovoltaic performance, with an increase in short-circuit current density (Jsc) compared to the TiO2 DSSC. This morphological improvement resulted in a notable enhancement of device performance, with efficiency increasing by approximately 62.5%. The increase in the efficiency of photovoltaic devices was attributed to the improvement achieved in band alignment as a result of the hybridization structure. This development reduces recombination processes and promotes charge transfer, as demonstrated by electrochemical impedance measurements. The spatial separation between electrons and holes in the ZnO/ZnS structure, combined with the role of reduced graphene oxide (rGO) as an efficient electron acceptor, contributes to these improvements.
Author(s): Thiago Kurz Pedra, Ramon Dadalto Carvalho, Cristian Dias Fernandes, Eduardo Ceretta Moreira, Carolina Ferreira de Matos Jauris, Elson Longo, Mateus Meneghetti Ferrer, Cristiane Wienke Raubach, Sérgio da Silva Cava, Pedro Lovato Gomes Jardim, Mario Lucio Moreira
First published: 03/12/2025
DOI: 10.1039/D5DT02045J
