DFT study of X‐site ion substitution doping of Cs ₂ PtX ₆ on its structural and electronic properties

Abstract

Summary The stability and toxicity of perovskite solar cells are still preventing full industrialization. Therefore, lead‐free all‐inorganic double perovskite materials have become the focus of research in recent years. Our group proposed a new narrow bandgap lead‐free double perovskite solar cell using a high‐quality Cs2PtI6 film. In this paper, for the purpose of exploring the trend in the bandgap and stability of the perovskite‐derived Cs2PtI6 substituted by halogen ions, we performed a first‐principles investigation based on density functional theory to study the structural and electronic properties of Cs2PtI6−yCly, Cs2PtI6−yBry, Cs2PtBr6−yCly (y = 0, 1, 2, 3, 4, 5, 6). The calculated structural parameters revealed a good mechanical stability for all these compounds, and the trend in the formation energy indicated that the substitution of I− with Cl− and Br− can significantly reduce the energy and improve the thermodynamic stability. Through a comparative analysis of the electronic properties of Cs2PtX6 (X = Cl, Br, I), we found that the substitutional doping of halogen ions can effectively adjust the bandgap and show an obvious change trend. The present study may demonstrate an effective theoretical guidance for preparing lead‐free all‐inorganic perovskite solar cell materials with appropriate bandgap and excellent stability.

Acid‐ and Base‐Stable Cs2Pt(Cl,Br)6 Vacancy‐Ordered Double Perovskites and Their Core–Shell Heterostructures for Solar Water Oxidation

“…[51] It has been hypothesized that poor spin-orbit coupling between Pt and Br led to the indirect bandgap. A similar variation in the nature of bandgap has been reported by Ma et al [52] The fluorescence imaging of these Cs 2 PtCl 6 and core-shell structures after two and four hours of immersion was carried out. Comparing the transmission and fluorescence images (Figure 3c), it can be noted that the parent particle made of Cs 2 PtCl 6 shows complete emission.…”

Predicting Sulfur‐Rich Oxysulfide Perovskites for Water‐Splitting Applications Using Machine Learning

“…To assert the thermodynamic stability, we compute the formation energy of the predicted seven potential new ABOS 2 perovskite compounds using the GGA‐PBE exchange‐correlation functional. The formation energy is the difference between the total energy of the host compounds and the sum of the energies of its major constituents in their standard form [ 32,33 ] , and thus can be given as $$$$\begin{equation} {E}_{\text{f}}={E}_{({\text{ABOS}}_{2})}-{E}_{\text{A}}-{E}_{\text{B}}-{E}_{\text{O}}-2{E}_{\text{S}} \end{equation}$$$$…”

Lead-free Perovskites TlGeClxBr3-x (x=0,1,2,3) as Promising Materials for Solar Cell Application: a DFT Study

“…This is generally true for a large range of ABX3 perovskite compounds, where X anions are replaced by their counterparts with larger ionic radii [67][68][69][70][71][72]. This is also observed for double perovskites [73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92]. The optimized lattice constants of TlGeCl3, TlGeCl2Br, TlGeClBr2, and TlG perovskites are 5.244 Å, 5.336 Å, 5.416 Å, and 5.501 Å, respectively (Table 1).…”