The Dion–Jacobson perovskite CsSbCl4: a promising Pb-free solar-cell absorber with optimal bandgap ∼1.4 eV, strong optical absorption ∼105 cm−1, and large power-conversion efficiency above 20%

A novel Pb-free perovskite CsSbCl₄is found with a direct bandgap 1.41 eV, strong optical absorption 105 cm⁻¹, high hole mobility 104 cm²V⁻¹s⁻¹, and large PCE > 20%.