Visible light response, electrical transport, and amorphization in compressed organolead iodine perovskites

Abstract

Recent scientific advances on organic-inorganic hybrid perovskites are mainly focused on the improvement of power conversion efficiency. So far, how compression tunes their electronic and structural properties remains less understood. By combining in situ photocurrent, impedance spectroscopy, and X-ray diffraction (XRD) measurements, we have studied the electrical transport and structural properties of compressed CH3NH3PbI3 (MAPbI3) nanorods. The visible light response of MAPbI3 remains robust below 3 GPa while it is suppressed when it becomes amorphous. Pressure-induced electrical transport properties of MAPbI3 including resistance, relaxation frequency, and relative permittivity have been investigated under pressure up to 8.5 GPa by in situ impedance spectroscopy measurements. These results indicate that the discontinuous changes of these physical parameters occur around the structural phase transition pressure. The XRD studies of MAPbI3 under high pressure up to 20.9 GPa show that a phase transformation below 0.7 GPa, could be attributed to the tilting and distortion of PbI6 octahedra. And pressure-induced amorphization is reversible at a low density amorphous state but irreversible at a relatively higher density state. Furthermore, the MAPbI3 nanorods crush into nanopieces around 0.9 GPa which helps us to explain why the mixed phase of tetragonal and orthorhombic was observed at 0.5 GPa. The pressure modulated changes of electrical transport and visible light response properties open up a new approach for exploring CH3NH3PbI3-based photo-electronic applications.

High-pressure behavior of methylammonium lead iodide (MAPbI3) hybrid perovskite

“…10). 9,10 It is interesting to observe that, while this lowpressure phase transition occurs at the same pressure for all the experiment carried out so far on the MAPbI3, i.e. refs.…”

“…Also in this work, the authors did not used any P-transmitting medium, thus suggesting, as in the case of ref. 9, that these structural data may be strongly dependent upon the absence of hydrostaticity in their measurements.…”

“…20 GPa. 9 However, in this work the authors did not employed any pressure transmitting medium and the XRD analysis was afforded in a qualitative way without reporting any lattice parameters value and trend as a function of the applied pressure. A more comprehensive study on the HP structural and optical properties of MAPbI3 was reported in arxiv by Wang et al 10 Main result of this work was the observation of a phase transition from tetragonal to orthorhombic phase around 0.3 GPa followed by partial amorphization of the sample up to the maximum Prange explored (ca.…”

Pressure-Induced Structural and Optical Properties of Organometal Halide Perovskite-Based Formamidinium Lead Bromide

“…[21][22][23][24] The pressure response of the optical and electronic properties of MAPbI 3 has also been investigated to delve into the structure-property relationship of perovskites. [24][25][26][27] Formamidinium lead bromide (NH 2 CH=NH 2 PbBr 3 , FAPbBr 3 ) possesses a bandgap of 2.23 eV under ambient conditions, which makes it more suitable for tandem application than MAPbBr 3 . 28 Hanusch et al reported a striking advantage of the FAPbBr 3 perovskites, that is, the material could be processed in a planar heterojunction configuration without a mesoporous scaffold for charge extraction.…”

Pressure‐Dependent Polymorphism and Band‐Gap Tuning of Methylammonium Lead Iodide Perovskite

“…221), in which all the BX 6 octahedra show B-X-B angles of 908 8.T his arrangement of untilted octahedra can be described in Glazer notation [14,15] as a 0 a 0 a 0 .Among the Pb-based methylammonium (MA) halide perovskites (ionic A = CH 3 NH 3 + or MA;X= Cl À ,B r À ,I À ;B= Pb 2+ ), the band gaps of MAPbCl 3 ,M APbBr 3 ,a nd MAPbI 3 are reported as around 3.1, 2.3, and 1.5 eV,r espectively. Although pressureinduced synchrotron powder X-ray diffraction (XRD) of MAPbI 3 was reported recently, [18] extraction of high-pressure lattice parameters,t he unambiguous determination of crystal symmetry and the refinement of atomic fractional coordinate are challenging. [17] Therefore,M APbI 3 is the preferred material.…”