Preferably Oriented Growth of Methylammonium-Based Perovskite Single Crystals with Ionic Liquid Solvent

Abstract

Crystalline orientation control is of great importance for the optoelectronic applications of perovskite single crystals due to their structural anisotropy. Herein, we develop an ionic liquid, named methylammonium difluoroacetate (MA2FAc), as a growth solvent to fabricate multifarious methylammonium-based perovskite single crystals. Typically, it can easily achieve preferably oriented growth of high-quality MAPbI3 single crystals with (002) facet exposition. Benefiting from the superior charge carrier properties along the [001] direction, a bias-modulating broadband/narrowband switchable photodetector is proposed, which exhibits a broadband specific detectivity D* of 1.1 × 1011 Jones under 0.1 V and a narrowband D* of 9.0 × 109 Jones with a full width at half-maximum (fwhm) of 31 at 810 nm merely under 0.25 mV, respectively. Theoretical calculations and experimental analysis reveal that the difluoromethyl substitution can simultaneously regulate solvation characteristics of the acetate anion as well as crystallization kinetics of perovskite single crystals. In light of the universal solvent utilization of MA2FAc, this work provides a new perspective in the solution growth process of high-quality methylammonium based perovskite single crystals.

Self‐Cleaning Perovskite Single Crystals Fabricated with Bis(trifluoromethylsulfonyl)imide Derived Ionic Liquid Toward High‐Performance Photodetection

“…based perovskite precursor solutions, demonstrating the BMITFSI possesses a stronger solvation ability than GBL that can dissociate the layered PbI 2 into smaller [PbI x ] 2-x intermediates. [28,29] Considering the ionic crystal nature of MAPbI 3 , the smaller intermediates should be helpful to restrain the bulky defect formation and improving the crystal quality. [28] With regard to the obtained crystal characteristics, either of the MAPbI 3 single crystals adopts a rhombic dodecahedron shape with top (200) facet exposition based on the X-ray diffraction (XRD) measurement shown in Figure S4 (Supporting Information), indicating the BMITFSI addition reserves the tetragonal structure and does not change the growth orientation of MAPbI 3 single crystal.…”

“…based perovskite precursor solutions, demonstrating the BMITFSI possesses a stronger solvation ability than GBL that can dissociate the layered PbI 2 into smaller [PbI x ] 2‐x intermediates. [ 28,29 ] Considering the ionic crystal nature of MAPbI 3 , the smaller intermediates should be helpful to restrain the bulky defect formation and improving the crystal quality. [ 28 ]…”