Pressure-Induced Polymorphic, Optical, and Electronic Transitions of Formamidinium Lead Iodide Perovskite.
Pan WangJiwen GuanDraven T K GaleschukYansun YaoCindy F HeShan JiangSijia ZhangYing LiuMeiling JinChangqing JinYang SongPublished in: The journal of physical chemistry letters (2017)
Formamidinium lead iodide (FAPbI3) perovskite as a superior solar cell material was investigated in two polymorphs at high pressures using in situ synchrotron X-ray diffraction, FTIR spectroscopy, photoluminescence (PL) spectroscopy, electrical conductivity (EC) measurements, and ab initio calculations. We identified two new structures (i.e., Imm2 and Immm) for α-FAPbI3 but only a structural distortion (in C2/c) for δ-FAPbI3 upon compression. A pressure-enhanced hydrogen bond plays a prominent role in structural modifications, as corroborated by FTIR spectroscopy. PL measurements and calculations consistently show the structure and pressure dependences of the band gap energies. Finally, EC measurements reveal drastically different transport properties of α- and δ-FAPbI3 at low pressures but a common trend to metallic states at high pressures. All of these observations suggest strongly contrasting structural stabilities and pressure-tuned optoelectric properties of the two FAPbI3 polymorphs.
Keyphrases
- high resolution
- density functional theory
- single molecule
- single cell
- molecular dynamics simulations
- molecular dynamics
- room temperature
- solid state
- stem cells
- cell therapy
- quantum dots
- mass spectrometry
- magnetic resonance imaging
- gene expression
- bone marrow
- drug induced
- magnetic resonance
- endothelial cells
- monte carlo
- solar cells
- crystal structure
- visible light
- dual energy