Orientational Dependence of Electron Beam Irradiation Damage in Lead-Free Halide Double Perovskite Cs₂AgBiBr₆

Abstract

Irradiation damage in halide perovskites usually enhances ion migration, decomposition, formation of intermediate phases, etc., which further decrease the working stability of halide perovskite optoelectronic devices. For example, due to the beam-sensitive nature of halide perovskites, the artifact information about local structures and microstructures is difficult to avoid during transmission electron microscopy (TEM) characterization. The interaction mechanism between high-energy electron beams and halide perovskites is still unclear. In this work, the electron-beam irradiation effect on solution-grown halide double perovskite Cs2AgBiBr6 crystals was systematically investigated by TEM. Depending on the different orientations of Cs2AgBiBr6, two kinds of electron beam irradiation damage were observed. When the irradiation on Cs2AgBiBr6 is along the [110]pc zone axis, a new phase Cs2Ag0.5BiBr6 with a vacancy-ordered superstructure forms, which is attributed to the “knock-on displacement” mechanism. In contrast, when the electron beams are along the [111]pc zone axis of Cs2AgBiBr6, an amorphous phase is gradually generated due to the “radiolysis” mechanism. Our finding clearly reveals the characteristics of irradiation damage in representative halide perovskites and further provides a new understanding of the working instability of halide perovskite optoelectronic devices.

Extending Absorption of Cs2AgBiBr6 to Near‐Infrared Region (≈1350 nm) with Intermediate Band

“…Figure S3b, Supporting Information exhibits the selected area electron diffraction (SAED) pattern of Fe-0.5 sample acquired along the zone axis of [1, −1, 0]. The pattern is consistent with the previous reported pattern for pristine Cs 2 AgBiBr 6 , [25] confirming the single crystalline phase and double perovskite structure of Fe doped Cs 2 AgBiBr 6 crystals. Furthermore, the high-resolution TEM (HRTEM) observation was also performed, which showed the perfect periodic arrangement of the atoms (Figure S3c,d, Supporting Information).…”

Aqueous Precursor Driven Cs2AgInCl6 Double Perovskite Nanocrystals Used as a Fluorescent Keypad Lock

“…UV–visible spectra exhibit a maximum wavelength at 297 nm (Figure a), which may arise due to a direct bandgap forbidden transition. ,, We have observed a long absorption tail in the UV–vis spectra. This tail appears due to the presence of a surface defect in the synthesized materials. − …”

“…Cs 2 AgBiX 6 is one of the important compounds in the double perovskite family. − The complete replacement of the Bi ion by the In ion in Cs 2 AgBiCl 6 double perovskite gives birth to Cs 2 AgInCl 6 double perovskite, which is not explored vastly in comparison to Cs 2 AgBiCl 6 even now . In the replacement of Ag, sodium ion-based halide double perovskites such as Cs 2 NaInCl 6 have been reported also. , Volonakis and their group reported Cs 2 AgInCl 6 , which is a potential solar cell absorber .…”