Effect of Sm doping into CuInTe₂ on cohesive energy before and after light absorption

The effects of Sm doping into CuInTe₂ chalcopyrite on the cohesive energy before and after light absorption are systematically investigated by the empirical electron theory (EET) of solids and molecules. The results show that the static energy of CuIn_1-xSm_xTe₂ decreases with Sm content increasing due to the valence electronic structure modulated by doping Sm into CuIn_1-xSm_xTe₂. The calculated optical absorption transition energy from the static state to the excited energy level in CuIn_1-xSm_xTe₂ accords well with the experimental absorption bandgap of CuIn_1-xSm_xTe₂. Moreover, it is found that the energy bandgap of CuIn_1-xSm_xTe₂ is significantly widened with Sm content increasing due to its special valent electron structure, which is favorable for enhancing the light absorption in a wider range and also for the potential applications in solar cells.