In-depth understanding the temperature-dependent reversible phase transition in CsPbI_3−xBr_x perovskites and its associated photophysical properties

Abstract

Although all-inorganic CsPbI3-xBrx (0 ≤ x ≤ 3) perovskites display largely potential toward the photoelectric applications, in-depth understanding the origin of phase transition and its associated photophysical properties are still...

Improvement in Stability and Storage Performance of All-Inorganic Perovskite CsPb(Br1–xIx)3 Memristors Based on Simple Halide Ion Migration

“…Meanwhile, the iodine ions affect the chemical environment of the bromide ions that may result from their noncovalent interaction, and the augmented interactions are favorable for the phase stability of CsPb(Br 1−x I x ) 3 QDs. 46,47 Consequently, the carrier transport process becomes more dependable, and the CsPb(Br 1−x I x ) 3 QD-based devices are expected to deliver a higher stability. To further understand the carrier transport properties and resistive switching mechanism of CsPb(Br 1−x I x ) 3 QD-based devices, we redrew the I−V curves on a double-logarithmic scale.…”

“…It is suggested that iodine ion doping mainly affects the chemical environment of the [PbX 6 ] 4– octahedron and advances the covalent interactions between lead ions and halide ions. Meanwhile, the iodine ions affect the chemical environment of the bromide ions that may result from their noncovalent interaction, and the augmented interactions are favorable for the phase stability of CsPb­(Br 1– x I x ) 3 QDs. , Consequently, the carrier transport process becomes more dependable, and the CsPb­(Br 1– x I x ) 3 QD-based devices are expected to deliver a higher stability.…”

Bromine Incorporation Affects Phase Transformations and Thermal Stability of Lead Halide Perovskites

“…LHPs are compounds with the chemical formula ABX 3 , where the A-site cation is commonly formamidinium (FA + ), and/or cesium (Cs + ); the B-site cation is lead (Pb 2+ ); and the X-site anion is iodine (I – ) and/or bromine (Br – ). , LHPs are characterized by corner-sharing PbX 6 octahedra and some degree of defect tolerance that lead to long-lived charge carriers. − However, these corner-sharing octahedra are not always thermodynamically phase stable at room temperature. − Inorganic CsPbI 3 goes through an undesirable phase transformation from the cubic (α) phase to the orthorhombic Pnma (δ) phase below 325 °C . FAPbI 3 spontaneously transforms from the cubic (α) phase to the undesirable hexagonal phases (2H-, 4H-, and 6H-FAPbI 3 ) , below 150 °C .…”

“…22−24 Inorganic CsPbI 3 goes through an undesirable phase transformation from the cubic (α) phase to the orthorhombic Pnma (δ) phase below 325 °C. 25 FAPbI 3 spontaneously transforms from the cubic (α) phase to the undesirable hexagonal phases (2H-, 4H-, and 6H-FAPbI 3 ) 26,27 below 150 °C. 28 Thermal instability is currently remediated by mixing both Cs and FA cations, 24 with single crystals of Cs 0.1 FA 0.9 PbI 3 showing a stable cubic phase at as low as 27 °C.…”

“…Single-cation systems have also seen improvement in thermal stability by mixing halides, such as stabilizing the tetragonal (β) phase as low as 100 °C by replacing 17% of iodine with bromine in CsPbI 3. …”