Investigations of the structural, electronic, and optical properties of Ti₃XC₂ (X = Ge, Pb, or Bi) by DFT

The global community currently faces significant challenges in meeting the rising demand for energy production. The development of clean energy technologies has gained substantial attention due to increasing energy shortages and worsening environmental degradation. Addressing these challenges requires the development of new materials. This study investigates the structural, electronic, and optical properties of Ti₃XC₂ (X = Ge, Pb, or Bi) MXenes, focusing on deintercalation and intercalation stages. The structural analysis demonstrates that the insertion and removal of Ge, Pb, and Bi within Ti₃XC₂ MXene significantly affect cell volume, with the second deintercalation stage exhibiting greater structural stability compared to the first. These MXenes exhibit metallic conductivity confirmed by density of states (DOS) calculations which reveal a zero band gap even with GGA corrections. The optical properties, including reflectivity, dielectric function and energy loss highlight distinct behavior among the intercalated structures, particularly for Ti3GeC2 which shows higher energy loss peaks in the 14-16 eV range. These findings provide valuable insights into the electronics and structural behavior of Ti₃XC₂ MXenes, making them promising candidates for advanced energy storage and electronic applications.