Theoretical and experimental investigation of a CuO and graphene embedded polyethylene oxide counter electrode for efficient DSSCs

Abstract

Dye-sensitized solar cells (DSSCs) have garnered significant attention due to their cost-effectiveness and ease of fabrication; however, the performance of counter electrodes (CEs) remains a critical factor in optimizing efficiency. In this study, we investigate the synergistic role of a polyethylene oxide (PEO)/copper oxide (CuO)/graphene (G) composite (PEO/CuO/G) as a CE for DSSCs, employing both theoretical modeling and experimental validation. DFT calculations were used for investigating PEO hybridization nanocomposites with different metal oxides, including MgO, SiO 2 , TiO 2 , NiO, CuO, ZnO, and ZrO 2 . The electronic properties analysis revealed that CuO is the most effective metal oxide in boosting the PEO polymer matrix, with a total dipole moment (TDM) of 10.482 Debye and ∆E of 0.422 eV. G is intended to strengthen the electrical characteristics of PEO/CuO by hybridizing with the optimal metal oxide. The hybrid composite of PEO/CuO/G showed significant improvement in electronic properties, with TDM of 18.7938 Debye ∆E 0.2566 eV. Interestingly, the morphological characteristics, electrical conductivity, surface roughness, and electrochemical properties of pure PEO, CuO, G, and PEO/CuO/G composites were systematically analyzed using Scanning Electron Microscopy (SEM), surface roughness, and electrical conductivity measurements. The results demonstrated a gradual enhancement in solar cell performance, with the optimized PEO/CuO/G composite exhibiting superior electrical conductivity (12.56 S/m), high surface roughness (8.1 µm), and an interconnected conductive network, facilitating efficient charge transfer. Photovoltaic (PV) measurements revealed a systematic improvement in short-circuit current density (J sc ) from 11.428 mA/cm 2 (PEO) to 16.916 mA/cm 2 (PEO/CuO/G) and fill factor (FF) from 63.4 to 65.1%, leading to a notable enhancement in overall efficiency from 4.33% to 6.42%. The observed improvements are attributed to the combined effects of CuO’s catalytic properties and graphene’s high electrical conductivity, forming a stable, efficient CE material. Theoretical modeling further supports these findings by demonstrating enhanced electron transport and reduced charge recombination within the composite structure. This study highlights the potential of PEO/CuO/G as a low-cost and high-performance CE for DSSCs, paving the way for further optimization in next-generation solar energy aerospace applications.

Topics & Concepts