## 1 Introduction  
Heterojunction with intrinsic thin layer (HIT) solar cells based on silicon \(a-Si:H/c-Si\) have reached efficiencies above 26% [1]. Interface quality and transport properties are the critical HIT solar cell factors for energy conversion [2]. Thus, several studies focus their efforts to improve the performance of \(a-Si:H/c-Si\) HIT solar cells by optimizing the quality of the interface and enhancing their transport properties [1; 2; 3]. The transparent conductive layer (TCL) is the layer responsible for separating and transporting photogenerated charge carriers to the cell terminals. This is due to the formation of a Schottky barrier in the electrode-silicon interface. At the same time, the TCL acts as an antiretive layer of internal reflections [1; 2; 3]. Thus, TCL must have low surface resistance and high optical transmission. Indium in oxide, one of the TCLs that is most used, has a resistance of \(\sim\)20 \(\Omega/\)sq, with 85% optical transmission and a high carrier mobility of 160 cm\({}^{2}\)/V\(\cdot\)s [1; 2; 3; 4; 5; 6]. In the last few years, two-dimensional nanomaterials, such as graphene, dichalcogenides (such as WS\({}_{2}\)), and Xenes (silicene, for example), have shown potential for several applications, such as drug delivery, sensing, energy storage, and transistors, among others [7; 8]. Regarding photovoltaics, several authors have reported on the use of thin films and graphene for solar cell applications, both experimentally and based on simulations. In perovskite solar cells, [PERSON] et al. [9] simulated, through the SCAPS program, the incorporation of a layer of copper oxide (CuO) with voids, and analyzed the influence on the energy bands and on the electrical properties of the solar cell. They optimized the design by varying the CuO thickness and the CuO doping concentration. With the optimization, they showed an increment in the conversion factor of 5.95%. In the study of [PERSON] et al. [10], a layer composed of PEDOT:PSS (PP) and graphene nanoplatelets (GNP) was studied as a counter electrode. They deposited it on FTO-coated glass and on bare glass, which served as substrates for the counter electrodes. The PP plate sample exhibited higher energy conversion than the sample that had PP:GNP when using the AM1.5 solar spectrum. Conversely, when using artificial light, the sample with the PP:GNP layer showed a higher energy conversion compared to the PP plate. [PERSON] et al. [11] presented a metamaterial absorber based on surface plasmon resonance (SPR). The structure consisted of (Graphene /SiO\({}_{2}\)/Au) matrix, and the simulation was conducted with COMSOL software. The absorber could achieve triple-mode perfect absorption, polarization independence, incident angle insensitivity, tunability, high sensitivity, and a high figure of merit (FOM). In [PERSON] et al. [12], the researchers demonstrated that the polarization-controlled multiple plasmon-induced transparency (PIT) depends on the symmetry in a graphene-based meta surface. The unit cell of the meta surface was composed of two U-shaped graphene nanostructures and one ring-shaped graphene nanostructure that is deposited on a dielectric substrate. For this study, they modeled through the finite time difference method, and they varied the configuration of the nanostructure. For each configuration, the maximum transition happens for different frequencies. Graphene has shown an interesting potential as a transparent conductor in several optoelectronic devices, such as LED, solar cells, touch screens, and so on [13; 14]. [PERSON] et al. [15] studied the incorporation of graphene as a transparent conductive layer in organic cells. For this purpose, they also included a Niquet grid below the graphene layer to enhance electrical conductivity. With this configuration, the efficiency of the organic cell was 4.2%, which was lower compared to the use of ITO (6.1%) due to a higher sheet resistance.