Anisotropy in Perovskite Single Crystals: From Fundamentals to Applications

Abstract

Single crystals of semiconductor materials have been extensively studied in optoelectronic applications because of the absence of grain boundary, lesser defects, and long-range order of crystallinity. Due to their multifaceted character, crystals are very often found to have significant anisotropic properties. These anisotropic properties lead to a considerable variation in their fundamental properties and optoelectronics applications. In the past decade, halide perovskites have emerged as one of the most exciting classes of semiconductors due to their rich photophysical properties leading to applications in solar cells, light-emitting diodes, photodetectors, etc. Especially, perovskite single crystals (PSCs) with an absence of grain boundaries, remarkably longer carrier diffusion lengths, significantly lower trap densities, and longrange order have received wide attention in large-scale device deployment. Interestingly, PSCs also exhibit strong anisotropy-dependent fundamental properties, and correspondingly their device applications are highly tunable. Here, in this feature article, we address a molecular perspective focusing on the structural, optical, and electronic anisotropy in PSCs. In addition, we discuss how anisotropy can affect the performance of PSCs-based devices. Furthermore, we highlight the future directions for implementing a fundamental understanding of the anisotropic response of PSCs to design novel and emergent optoelectronics devices.

Deciphering the Relevance of Quantum Confinement in the Optoelectronics of CsPbBr3 Perovskite Nanostructures

“…The average excited lifetimes are ∼21.41, 43.01, and 122.86 ns for the PNPL, PQD, and PNR, respectively. The higher anisotropy in the PNR affects the recombination process, leading to the variation in ion migration, a longer diffusion length along different planes, and a prolonged carrier lifetime . Another factor affecting the recombination dynamics is the presence of the surface defects.…”

“…The higher anisotropy in the PNR affects the recombination process, leading to the variation in ion migration, a longer diffusion length along different planes, and a prolonged carrier lifetime. 54 Another factor affecting the recombination dynamics is the presence of the surface defects. A comparison between E g values and average lifetimes versus confinement in Figure 2d suggests that the PNPL with a higher E g value come up with a lower lifetime and vice versa for the PQD and PNR.…”

Anisotropic carrier dynamics and laser-fabricated luminescent patterns on oriented single-crystal perovskite wafers

“…When taking the non-centrosymmetric equilibrium orientation of MA cation into account, the symmetry would be further decreased. From the steady-state perspective, the anisotropy in the electronic and optoelectronic behaviors of the pseudocubic perovskites is already a consensus, although the underlying mechanism is still under debate 27 , 28 . Whether this anisotropy influences the ultrafast excited-state dynamics has rarely been investigated.…”

Anisotropic Carrier Dynamics and Laser-Fabricated Luminescent Patterns on Oriented Single-Crystal Perovskite Wafers

“…From the steady-state perspective, the anisotropy in the electronic and optoelectronic behaviors of the pseudocubic perovskites is already a consensus, although the underlying mechanism is still under debate. 24,25 While whether this anisotropy influences the ultrafast excited-state dynamics has been rarely invesitagated. Here based on the availability of the high-quality and differently oriented crystal wafers, a transient-state investigation probing into the anisotropic ultrafast relaxation of photo-excited carrier was conducted aiming to obtain a more in-depth structure−function relations from a dynamic view.…”