Ferroelastic Domains Enhanced the Photoelectric Response in a CsPbBr₃ Single-Crystal Film Detector

Abstract

The ferroic domain, in metal halide perovskites (MHPs) at a low symmetry phase, was reported to affect optoelectronic properties. Building the relationship between ferroic domains and optoelectronic properties of MHPs will be a non-trivial task for understanding the charge transport mechanism. Here, high-quality CsPbBr3 single-crystal films (SCFs) were successfully grown by a cast-capping method. Through the phase transition process by heating and cooling the sample, dense domains in CsPbBr3 SCFs were formed and observed by an in situ polarized optical microscope. These domains were identified as 90° rotation twins by electron backscattered diffraction and transmission electron microscopy. Interestingly, the photocurrent response was dramatically enhanced after introducing ferroelastic domains. The highest responsivity, external quantum efficiency, and detectivity are 380 mA/W, 130%, and 12.9 × 1010 Jones, respectively, which are surprisingly 25.03, 25, and 7.8 times higher than those of the as-grown CsPbBr3 SCF, respectively, which may be attributed to the function of the domain wall of separating electrons and holes.

The Ferroelectric–Ferroelastic Debate about Metal Halide Perovskites

“…As a consequence, ferroelastic order is solely driven by the macroscopic build-up of strain but is not affected by the cation dynamics. Moreover, there is clear evidence that ferroelastic domain formation has a benign influence on charge-carrier transport, for example, enhancing the photoelectric response in CsPbBr 3 78 or inducing an anisotropy in the carrier diffusion in MAPbI 3 due to the presence of twin domains. 79 In fact, domain walls have been proposed to play a crucial role in the extremely long lifetimes of photogenerated charge carriers in MHPs.…”

Suppressing non-radiative recombination in metal halide perovskite solar cells by synergistic effect of ferroelasticity

“…Then, let's focus on the lattice polarization. Several recent studies suggest the existence of lattice polarization in MHP under stain 40,58,59 . Hence, it is reasonable to assume that the activation triggers the formation of lattice polarization as the self-sustainably elevated strain level is in good correlation with the V oc increment (Fig.…”

Structural Symmetry Impressing Carrier Dynamics of Halide Perovskite

“…For instance, the free ferroelastic domain structure of CsPbBr 3 transforms into the ferroelastic domain structure when the temperature decreases from 133 °C to room temperature. [127] Light, electric field, temperature, and pressure can be used not only to tune the phase transition and ferroelectric domain structure of MHPs, but also to adjust the phase transition and ferroelastic domain structure of all-inorganic lead halide perovskites, which significantly affect carrier dynamics and the energy conversion performance of MHP devices.…”