In recent years, Single-Junction Perovskite Solar Cells (SJ-PSCs) have emerged as a competitive alternative to silicon based solar cells in terms of efficiency. However, their stability under humidity and high-temperature conditions remains a major challenge [1]. In this context, the incorporation of 2D nanomaterials, such as MXenes, into SJ-PSCs offers a promising route to enhance both stability and efficiency [2]. Among these materials, Ti₃C₂T_x MXene stands out due to its excellent electrical conductivity and tunable electronic structure. The latter, along with its work function, can be controlled via surface terminal groups, which depend on synthesis methods and post-treatments [3]. In order to integrate Ti₃C₂T_x MXene into SJ-PSCs, morphological, chemical, and structural characterization, as well as a dispersibility study in typical organic solvents used during photovoltaic device fabrication, are required.

In this study, Ti₃C₂T_x MXene (T_x are -F, -O, and -OH terminal groups) was synthesized via wet chemistry under mild conditions from Ti₃AlC₂ (MAX phase). The resulting highly concentrated aqueous dispersion was used to prepare freestanding films via vacuum assisted filtration. X-ray Diffraction (XRD) analysis of the synthesized material revealed the successful etching of the MAX phase, since a typical pattern with a series of evenly spaced peaks corresponding to the characteristic (00X) (X = 2, 4, 6,…) family of planes of Ti₃C₂T_x was observed. Control of Ti₃C₂T_X flake thickness was achieved by optimizing centrifugation procedure. As a result, a suspension of single-layer or few-layered structure was obtained (where each layer shows a thickness of 1-1.5 nm and lateral dimensions in the micrometer range (1-10 μm)) as revealed using Atomic Force Microscopy. When studying dispersibility of Ti₃C₂T_x MXene in solvents involved to SJ-PSC fabrication, it was found that polar solvents promote dispersion, in contrast to non-polar ones, which correlates with the presence of -O and -OH as MXene-terminal groups. Additionally, aprotic solvents showed better dispersibility than protic solvents. UV-Vis Spectrophotometry characterization showed the characteristic 750-800 nm absorption band, attributed to Ti₃C₂T_x MXene localized surface plasmon resonance (LSPR). The LSPR absorbance as a function of concentration was analyzed in selected organic solvents, enabling the determination of absorption coefficients.

The obtained results lay the basis for obtaining Ti₃C₂T_x MXene dispersions with controlled concentrations, facilitating their further integration into SJ-PSCs. In addition, the challenges of creating Ti₃C₂T_x nanocomposites with metal nanoparticles for modulating the work function will be discussed.