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

Abstract

Organometal halide perovskites (OMHPs) are attracting an ever-growing scientific interest as photovoltaic materials with moderate cost and compelling properties. In this Letter, pressure-induced optical and structural changes of OMHP-based formamidinium lead bromide (FAPbBr3) were systematically investigated. We studied the pressure dependence of optical absorption and photoluminescence, both of which showed piezochromism. Synchrotron X-ray diffraction indicated that FAPbBr3 underwent two phase transitions and subsequent amorphization, leading directly to the bandgap evolution with redshift followed by blueshift during compression. Raman experiments illustrated the high pressure behavior of organic cation and the surrounding inorganic octahedra. Additionally, the effect of cation size and the different intermolecular interactions between organic cation and inorganic octahedra result in the fact that FAPbBr3 is less compressible than the reported methylammonium lead bromide (MAPbBr3). High pressure studies of the structural evolution and optical properties of OMHPs provide important clues in optimizing photovoltaic performance and help to design novel OMHPs with higher stimuli-resistant ability.

Large Band Gap Narrowing and Prolonged Carrier Lifetime of (C4H9NH3)2PbI4 under High Pressure

“…[12] The hydrophobic molecules in the organic layers effectively improve the moisture resistance compared to the 3D perovskite, which solves the main obstacle of 3D OIHPs. [21][22][23][24][25] For example, Wang et al studied the structural transition and photoresponse of CH 3 NH 3 PbBr 3 (MAPbBr 3 ) under pressure. [15,16] The alternating layers of 2D lead-halide perovskites induce an exceptionally large exciton binding energy [15,17] and a wide band gap in contrast to 3D lead-halide perovskites, which limits its optical performance.…”

“…[15,16] The alternating layers of 2D lead-halide perovskites induce an exceptionally large exciton binding energy [15,17] and a wide band gap in contrast to 3D lead-halide perovskites, which limits its optical performance. Wang et al observed that pressure can efficiently reduce the band gap of formamidinium lead bromide (FAPbBr 3 ) [22] and methylammonium lead chloride Due to their superior optical and electronic properties and good stability, 2D organic-inorganic halide perovskites (OIHPs) exhibit strong potential for optoelectronic applications. Therefore, reducing the band gap and prolonging the carrier lifetime are two critical issues to be considered when improving the performance of 2D lead-halide perovskites for practical applications.…”

“…[21] Their results suggest that hydrostatic pressure can significantly affect the crystal structure and photovoltaic related properties of MAPbBr 3 . Wang et al observed that pressure can efficiently reduce the band gap of formamidinium lead bromide (FAPbBr 3 ) [22] and methylammonium lead chloride Due to their superior optical and electronic properties and good stability, 2D organic-inorganic halide perovskites (OIHPs) exhibit strong potential for optoelectronic applications. However, the large band gap, short carrier lifetime, and high resistance hinder their practical performance.…”

“…[21][22][23]25,48] However, due to their low structural stability, the enhancement is limited. [21][22][23]25,48] However, due to their low structural stability, the enhancement is limited.…”

Metal Halide Perovskites: From Crystal Formations to Light‐Emitting‐Diode Applications

“…2D nanoplates and 1D nanowires can be formed by ligand engineering, reaction‐temperature engineering, purification, ultrasonication, A‐site‐cation engineering, or by using additives . Furthermore, the synthesized MHP NCs can be also post‐transformed from 3 nm thick CsPbBr 3 nanosheets to Pb nanoparticle (NP)–CsPbBr 3 nanocomposites by electron beams, from 2D CsPbBr 3 nanoplatelets to larger structures such as nanobelts or square‐shaped nanodisks by photoirradiation, or from cubic phase to orthorhombic phase in FAPbBr 3 crystals by pressure …”