Electron beam evaporated Cu–Zn–Te-In chalcogenide-based thin films for dye-sensitized solar cell and thermoelectric applications

Recent improvements in copper telluride and copper chalcogenide thin films have attracted substantial interest due to their potential credit for opto-electronic and thermoelectric applications. In this work, the structural and morphological evolution of copper–zinc–telluride-Indium (Cu–Zn–Te-In) thin-film is explored through combined experimental and theoretical approaches. In addition, phase engineering of copper telluride-based nanostructured thinfilm is shown to be critical when used as back contacts in Cu–Zn–Te-In dye-sensitised solar cells (DSSCs). Using a co-evaporation technique followed by rapid thermal processing, the Cu/Zn/Te/In ratio is precisely adjusted to achieve single-phase Cu–Zn–Te-In thin films. The as-deposited films are primarily slightly amorphous but transform into crystalline single or mixed phases upon annealing. Such controlled phase evolution is vital for enhancing the efficiency of Cu–Zn–Te-In based solar devices and for improved thermoelectric applications. Sample 1 (Cu 0.59 Zn 0.33 Te 0.07 In 0.01 ) is 12% improved over the sample 2 (Cu 0.65 Zn 0.30 Te 0.04 In 0.01 ) respectively in Figure of merit emphasizes only the core contributions of this work, including compositional regulation (Cu–Zn–Te-In ratio), structural and morphological evolution, optical band-gap tuning, and key Photo voltaic performance parameters of the optimized device and Seebeck effect too.