All inorganic lead free solar cell material Cs_2PdI_6: a first-principles study

摘要

Through first-principles calculations, the photovoltaic properties of Cs2PdI6 were investigated and found that (i) Cs2PdI6 has a quasi-direct band gap nature, and strong p-d coupling of lower conduction bands is responsible for light electrons; (ii) dominant Pd-i and I-i defects would be produced at a deep level in the band gap which acts as charge trapping states. Thus, should be passivated by suitable external doping, if Cs2PdI6 works as a solar cell absorber; (iii) The Cs2Pd(I1-xBrx)(6) alloy is highly miscible. Tunable band gap depending on composition x has a non-linear bowing behavior occurring a lowest band gap at composition Cs2Pd(I0.7Br0.3)(6).