The structural and electronic properties of Cu(In1-xBx)Se-2 as a new photovoltaic material

摘要

The newly synthesized solar cell absorber material Cu(In1-xBx)Se-2 based on a solvothermal method with a special solvent is investigated using density functional theory. Our results show that Cu(In1-xBx)Se-2 has an extremely high formation enthalpy which indicates that it is hard to synthesize using a traditional evaporation method. The band gap of Cu(In1-xBx)Se-2 increases with increasing B content with a larger bowing parameter than that of Cu(In1-xBx)Se-2. The band alignment of CuInSe2 and CuBSe2 is of type II. And the upshift of the valence band maximum is much smaller than that of the conduction band maximum for CuBSe2, which indicates that pure CuBSe2 can easily be p-type doped but that n-type doping could be more difficult in the alloy with a high B content. Therefore, we expect that the high efficiency Cu(In1-xBx)Se-2 solar cell material has a low B content.