Insights into the Impact of Fe-Doped CsPbCl₃ Perovskites on Stability and Luminescence: A First-Principles Investigation

Thetransition metal-doped CsPbX3 family is regardedas promising materials to be applied in optoelectronic devices. However,the understanding of the underlying luminescence mechanism is stilllimited. In our study, the mechanism of dual emission for Fe-dopedCsPbCl(3) is determined from the first-principles methods.Fe doping can cause lattice compression and octahedral deformationand importantly improve the stability of CsPbCl3 well.The spin-included band structure calculation shows that the Fe concentrationmainly modulates the energy level position of e(g) (& DARR;) (Fe 3d spin-down state). The e(g) (& DARR;) locationin the band gap and near the conduction band minimum can induce efficientenergy transfer from the conduction band minimum to the e(g) (& DARR;) state, which leads to the electronic transitione(g) (& DARR;) & RARR; t(2g) (& DARR;) of the Fe ion further. The experimental dual emission is confirmedby the calculated band gaps between band edges and between e(g) (& DARR;) and t(2g) (& DARR;) states(Fe 3d spin-down state). According to the analysis of density of states,the e(g) (& DARR;) and t(2g) (& DARR;) states are broad in the larger octahedral deformation, which suggeststhe experimental broadband emission of the Fe ion. The optical absorptionof CsPbCl3 is improved and blue-shifted upon Fe doping,also in agreement with experiments. Our findings provide the understandingfor designing high-performance doped perovskite optoelectronic devices.