## 3 Results and Discussion
### Electrical and Optical Properties, Raman Scattering and DFT Calculations  
The conductivity, mobility, magnetoresistance, and carrier concentrations were measured using the van [PERSON] method. Room-temperature Hall-effect measurements were conducted with a magnetic field intensity of 0.556 T and a current of 0.5 mA. The measured conductivity, mobility, carrier concentration, and magnetoresistance values are listed in Table 3.  
All the CuCr\({}_{2\cdot 3}\)Sn\({}_{3\cdot 2}\)S\({}_{2\cdot 3}\)Se\({}_{1\cdot 7}\) and CuCr\({}_{2\cdot 3}\)Sn\({}_{3\cdot 1}\)\(\cdot\)S\({}_{2\cdot 3}\) (x = 0.4, 0.6, and 1.0) samples showed p-type conductivity, which was consistent with the results reported for CuCr\({}_{2\cdot 3}\)Sn\({}_{3\cdot 4}\) and CuCr\({}_{2\cdot 3}\)Sb\({}_{3}\)S\({}_{4}\)[23; 36]. The temperature dependence electrical conductivity for CuCr\({}_{1\cdot 4}\)Sn\({}_{0\cdot 6}\)S\({}_{1\cdot 7}\)Se\({}_{2\cdot 3}\) and CuCr\({}_{1\cdot 6}\)Sn\({}_{0\cdot 4}\)S\({}_{1\cdot 7}\)Se\({}_{2\cdot 3}\) is shown in Figure S3. The electrical conductivity (\(\sigma\)) increased almost exponentially with increasing temperature, revealing semiconductor behavior for the sample, followed by a temperature dependence of \(\sigma\)\(\sim\)T\({}^{n}\). The Hall coefficients were positive at RT, which is indicative of p-type behavior. The hole concentrations were similar at all studied phases, with a carrier concentration of approximately 10\({}^{20}\) cm\({}^{-3}\). [PERSON] et al. reported values of approximately 2.41 \(\times\) 10\({}^{21}\) cm\({}^{-3}\) for CuCr\({}_{1\cdot 5}\)Sb\({}_{0\cdot 5}\)S\({}_{4}\), which showed typical degenerate semiconductor behavior. Electrical mobility is an important property for evaluating electrical behavior. The electrical hole mobilities of CuCr\({}_{2\cdot 3}\)Sn\({}_{3\cdot 2}\)S\({}_{1\cdot 7}\) and CuCr\({}_{2\cdot 3}\)Sn\({}_{3\cdot 1}\)\(\cdot\)S\({}_{2\cdot 3}\) (\(\sim\)0.10 cm\({}^{2}\)/V\(\cdot\)s) were smaller than the value reported for CuCr\({}_{1\cdot 5}\)Sb\({}_{0\cdot 5}\)S\({}_{4}\) (4.06 cm\({}^{2}\)/V\(\cdot\)s). The chalcogen S/Se substitution thus led to low mobility. The electrical conductivities, \(\sigma\), of the CuCr\({}_{1\cdot 0}\)Sn\({}_{1\cdot 0}\)S\({}_{2\cdot 5}\)Se\({}_{2\cdot 5}\), CuCr\({}_{2\cdot 3}\)Sn\({}_{3\cdot 2}\)S\({}_{2\cdot 5}\)I\({}_{7}\), and CuCr\({}_{2\cdot 3}\)Sn\({}_{3\cdot 1}\)\(\cdot\)S\({}_{2\cdot 3}\) phases were lower than those of the CuCr\({}_{2}\)Se\({}_{4}\) (667 S/cm) and CuCr\({}_{2\cdot 5}\)S\({}_{4}\) (1110 S/cm) end-members. This  
\begin{table}
\begin{tabular}{c c c c} \hline  & \(a\) (Å) & _R\({}_{\mathbf{P}}\)_ & _R\({}_{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\indicates that \(\sigma\) is quite sensitive to the Sn content. The electrical conductivity \(\sigma\) showed chromium-content dependence, and it increased in all cases with decreasing x values. The only exception was the CuCr\({}_{1\text{-}}\)\(\epsilon\)Sn\({}_{0\text{-}}\)4S\({}_{2\text{-}}\)3 Se\({}_{1\text{-}}\)7 sample, which had the lowest \(\sigma\) value. This sample showed a complex chemical composition related to chromium content; the Rietveld analysis refinement performed for this sample indicated the presence of minor phase impurities. Therefore, such as inhomogeneity could be responsible for the exceptional conductivity values. On the other hand, the \(\sigma\) value for CuCr\({}_{1\text{-}}\)6 Sn\({}_{0\text{-}}\)4S\({}_{1\text{-}}\)7 Se\({}_{2\text{-}}\)3 was approximately 2 times larger than the value obtained for CuCr\({}_{1\text{-}}\)4 Sn\({}_{0\text{-}}\)5S\({}_{1\text{-}}\)5 Se\({}_{2\text{-}}\)3 and approximately 80 times larger than that of CuCr\({}_{1\text{-}}\)0 Sn\({}_{1\text{-}}\)5S\({}_{2\text{-}}\)0 Se\({}_{2\text{-}}\)0. This suggests that the chromium content is the main reason for the increased conductivity in these systems.