Secondary Phase Particles in Cesium Lead Bromide Perovskite Crystals: An Insight into the Formation of Matrix-Controlled Inclusion

Abstract

The metal halide perovskite CsPbBr 3 bulk crystals present electrical and optical performance discrepancy since the grown-in defects. Here, we first report the well-defined secondary phase (SP) particles of CsPb 2 Br 5 with polyhedral morphology in CsPbBr 3 crystals grown by the vertical Bridgman method. The resulting polyhedral morphology of CsPb 2 Br 5 particles associated with the trapping of PbBr 2 -rich droplets have been discussed on the basis of the "matrix-controlled" growth. Two morphological evolution paths are proposed, which result in a regular cube SP particle comprised by {100} facets for the final equilibrium. Furthermore, the wafer with superior optical transmittance exhibits a higher photoelectric response on−off ratio (∼2000) in contrast to ∼80 for the wafer with high density SP particles. The corresponding hole mobility (μ h ) is calculated with the values 289.99 and 26.91 cm −2 • V −1 •s −1 , respectively. The variation of μ h is attributed to the carrier transport trajectory affected by SP induced trapping defects and the weak combination.

Ultralow Detection Limit and Robust Hard X-ray Imaging Detector Based on Inch-Sized Lead-Free Perovskite Cs3Bi2Br9 Single Crystals

“…°C) and boiling point (1300 °C) of CsBr, when the CBB polycrystal was synthesized at 660 °C, the CsBr had melted, but a part of BiBr 3 formed a gas phase in the silica ampoule. 17 Therefore, a trace of CsBr was present in the CBB polycrystal. Owing to constitutional supercooling during the CBB SC growth, the CsBr-rich phases were easily trapped in the crystal−melt interface.…”

“…Owing to constitutional supercooling during the CBB SC growth, the CsBr-rich phases were easily trapped in the crystal−melt interface. 17 As shown in Figure 2c, the capture process of the inclusions was as follows: Crystal steps were formed at the interface during crystal growth. As the growth rate of CBB-1 SC (f s ) was extremely high, pits appeared at the unstable solid−liquid interface and the superheated melt grew into the CBB crystal.…”

“…However, a high bias can significantly increase the dark current noise and current drift caused by the relatively low resistivity and strong ionic migration in most three-dimensional (3D) perovskites, respectively, which can deteriorate the resolution and stability of the detector. 13 Several strategies have been proposed to suppress the noise current and current drift, for instance, the development of lowdimensional perovskite SCs with high ion activation energies, 16 quality enhancement of SCs by restraining defects, 17 passivation of the crystal surface, 9 construction of heterostructures or induction of the inner electric field, 18 and preapplication of the reverse voltage for crystal devices. 19 Among these strategies, growth of novel two-dimensional (2D) halides including the Ruddlesden−Popper-type, Dion−Jacobson-type, and other layered all-inorganic perovskites is an attractive technique to enhance the performance of detectors owing to the diverse composition and structure of perovskites.…”

Precursor Engineering for Solution Method-Grown Spectroscopy-Grade CsPbBr3 Crystals with High Energy Resolution

“…However, the precursor solution with PbBr 2 •2DMSO looks much clearer, and the obtained CPB exhibits higher optical diaphaneity. The singlecrystal transmittance reflects its crystallization quality, which is usually dominated by the grown-in defects associated with the secondary particle phase, 39 impurities, and dislocations. Figure 1e demonstrates the concentration of the typical impurities in CPB crystals.…”

CsPbBr3@Cs4PbBr6 Emitter-in-Host Composite: Fluorescence Origin and Interphase Energy Transfer

“…The different situation is that the emission origin in CsPb 2 Br 5 is now clearly disclosed; concrete evidence has been shown to elucidate CsPbBr 3 being the emissive center, , while CsPb 2 Br 5 itself is inherently PL-inactive . Indeed, the low chemical stability, causing facile interconversions, , renders the ready coexistence of the three types of compounds during synthesis, and usually in the form of a dominant host containing a minor guest that can be quite difficult to detect. In our opinion, 0D HP shares this phenomenon, as has been gradually revealed by the solid experimental progress summarized above.…”