## 1 Introduction  
The evolution of electronic technology has been linked in a parallel way to the continuous miniaturization of its components, and to the development of new materials with improved optoelectronic properties. For instance, two-dimensional (2D) transition metal dichalcogenides (TMDs) have received a great deal of attention due to their superior electrical properties [1, 2]. In TMDs such as MX\({}_{2}\), M is a transition metal (Mo, W, Ti, Zr, Hf, V, Nb, Ta, Tc, Re, Pd, Pt) and X is a chalcogen (S, Se, Te) [3]. TMDs consist of a variety of materials with diverse electronic properties ranging from insulators (e.g., HfS\({}_{2}\)), semiconductors (e.g., MoS\({}_{2}\), MoSe\({}_{2}\), WS\({}_{2}\), WSe\({}_{2}\) NbSe\({}_{2}\) and TaS\({}_{2}\)), semimetals (e.g., TiSe\({}_{2}\) and WTe\({}_{2}\)) and metals (e.g., NbS\({}_{2}\) and VSe\({}_{2}\)) [1, 3]. Additionally, the advantage of these 2D materials is their adjustable properties, a consequence of the compositional and structural features of their construction components, which allow their introduction in supercapacitors, batteries, solar cells and sensing applications [1]. Regarding their optoelectrical parameters, TMDs have shown good charge carrier mobility, a direct bandgap, good stability and good performance as a hole transport layer (HTL) [3, 4]. For instance, a wide variety of TMDs have been investigated as counter electrodes for dye sensing, substituting the conventional Pt electrode,where an increase or decrease in the solar cell parameters has been reported depending on the TMD, number of layers, microstructure, deposition process and annealing process [2]. In addition to 2D chalcogenides, 2D oxides have been considered within the family of 2D materials [2,3]. The development of nanomaterials formed by transition metal oxides, conductors, superconductors, light emitters, dielectrics, magnetics and ferroelectrics proves that these types of metal oxides form a series of compounds that give place to a diversity of applications that can only be found in this type of material. In this regard, copper bismuth oxide (CuBi\({}_{2}\)O\({}_{4}\)) is an attractive p-type semiconductor with a bandgap of 1.5-1.8 eV [5], which could take advantage of a large portion of the visible spectrum for optoelectronic applications. The structure of CuBi\({}_{2}\)O\({}_{4}\), space group P4/ncc and tetragonal symmetry was discovered by [PERSON] et al. in 2001 [6]. CuBi\({}_{2}\)O\({}_{4}\) nanoparticles (NPs) have been obtained by different methodologies such as solid-state reaction [7, 8, 9], the hydrothermal method [10], the sonochemical approach [11] and the sol-gel method [12], as well as an innovative and environmentally friendly one-step synthesis method [13]. Until now, the main applications of this oxide are in photocatalysis, generation of hydrogen from H\({}_{2}\)O, degradation of water contaminants such as dyes and as microbicides [5, 13, 14, 15, 16]. Moreover, under AM1.5 and EQE (external quantum efficiency) equal to 1, the maximum theorical Jsc is 29 mA/cm\({}^{2}\), which potentiates its use for solar cell applications [17]. Nevertheless, although CuBi\({}_{2}\)O\({}_{4}\) NPs have a low bandgap [5, 18, 19, 20], their semiconductor behavior has not been studied, and their possible application in optoelectronic devices has not been studied either. Regarding the above, it is required that CuBi\({}_{2}\)O\({}_{4}\) NPs form part of semiconductor thin films which are integrated into various devices [20, 21, 22, 23, 24, 25]. The study of the semiconductor behavior of CuBi\({}_{2}\)O\({}_{4}\) NPs, when they are part of composite films, should be expanded. Composite films have gained importance in optoelectronics since they combine the electrical properties of NPs with the properties of the polymeric matrix in which they are embedded. The construction of these heterojunctions is an important aspect that can separate electron/hole pairs in semiconductors [23, 26, 27].