Formamidinium lead iodide ( FAPbI3cap F cap A cap P b cap I sub 3
) is a premier hybrid organic-inorganic perovskite (HOIP) favored for high-efficiency solar cells due to its near-ideal band gap of approximately
. Crystallographic Information Files (CIF) are the standard for modeling its structure, essential for both theoretical simulations and experimental X-ray diffraction (XRD) analysis. Structural Phases and Crystallography FAPbI3cap F cap A cap P b cap I sub 3
primarily exists in two major polymorphs at room temperature: the photoactive -phase (black) and the non-perovskite -phase (yellow).
-Phase (Cubic Perovskite): This is the desired phase for photovoltaics. It typically crystallizes in the
space group (No. 221). The structure consists of a corner-sharing PbI6cap P b cap I sub 6 octahedral framework with formamidinium ( FA+cap F cap A raised to the positive power
) cations occupying the 12-fold coordinated cuboctahedral cavities. -Phase (Hexagonal): At room temperature, the -phase is metastable and often transitions into the yellow
-phase, which features face-sharing octahedra and is unsuitable for solar applications due to its wide band gap (~ Key CIF Parameters for FAPbI3cap F cap A cap P b cap I sub 3 Standard CIF data for the cubic phase at approximately typically includes: Lattice Constant ( ): Roughly Cell Volume: ~ FA+cap F cap A raised to the positive power Cation Orientation: The organic FA+cap F cap A raised to the positive power
) is dynamically disordered within the inorganic cage. CIF models often represent this via multiple occupancy sites or specific orientation minimizations, such as the fragment lying in the CIF Data Sources and Tools High-quality CIF files for FAPbI3cap F cap A cap P b cap I sub 3
can be accessed through academic repositories and open databases: Description Crystallography Open Database (COD) A standard repository for experimental crystal structures. Materials Project
Provides DFT-relaxed structures and computational CIFs for perovskite materials. GitHub (WMD-group)
Hosts specific FAPbI3 CIF files used in prominent hybrid perovskite research. Cambridge Structural Database (CSD) Essential for verified experimental single-crystal data. Visualization and Analysis To utilize a CIF file: FAPbI3.cif - WMD-group/hybrid-perovskites - GitHub
hybrid-perovskites/2014_cubic_halides_PBEsol/FAPbI3. cif at master · WMD-group/hybrid-perovskites · GitHub. FAPbI3_tetragonal&cubic - 科学数据银行
FAPbI₃ CIF File: The Structural Blueprint of Formamidinium Lead Iodide
In the rapidly evolving world of perovskite photovoltaics, FAPbI₃ (Formamidinium Lead Iodide) has emerged as the "gold standard" material. To understand why this material is shattering efficiency records, researchers rely on a critical document: the CIF file.
A Crystallographic Information File (CIF) is the standard text file format for representing crystallographic data. For FAPbI₃, the CIF file is the essential map that tells us exactly where every atom—Formamidinium, Lead, and Iodine—sits in 3D space. Why the FAPbI₃ CIF File is Essential
Researchers download and utilize FAPbI₃ CIF files for several primary reasons:
DFT Simulations: Density Functional Theory (DFT) calculations require precise atomic coordinates to predict electronic band structures, charge carrier mobility, and stability.
XRD Analysis: By comparing experimental X-ray Diffraction (XRD) patterns with the theoretical pattern generated from a CIF file, scientists can confirm if they have successfully synthesized the desired phase.
Visual Modeling: Software like VESTA or Mercury uses CIF data to create the iconic "ball-and-stick" models of the perovskite lattice. Structural Phases of FAPbI₃
The complexity of the FAPbI₃ CIF file lies in its polymorphism. Depending on temperature and synthesis conditions, the material can exist in several phases:
α-phase (Alpha): The cubic (or near-cubic) black phase. This is the photoactive phase used in solar cells because its bandgap (~1.48 eV) is nearly ideal for capturing sunlight.
δ-phase (Delta): The hexagonal yellow phase. This is thermodynamically stable at room temperature but electronically inactive, making it the "enemy" of high-efficiency solar cells.
When searching for a CIF file, it is crucial to distinguish between these phases, as the lattice parameters ( ) and space groups (e.g., for cubic or P63mccap P 6 sub 3 m c for hexagonal) differ significantly. Key Parameters Inside the CIF A standard FAPbI₃ CIF file contains:
_cell_length_a, b, c: The dimensions of the unit cell (typically around 6.36 Å for the cubic phase).
_cell_angle_alpha, beta, gamma: Usually 90° for the cubic system.
_symmetry_space_group_name_H-M: Defines the symmetry operations of the crystal. Atomic Coordinates: The positions of the Pb²⁺, I⁻, and the FA⁺ (
The "FA" Challenge: Unlike simple inorganic perovskites (like CsPbI₃), the Formamidinium cation is a molecule. In a CIF file, this often introduces disorder. The FA molecule can rotate within its iodine cage, meaning many CIF files represent the nitrogen and carbon atoms with "occupancy" factors to account for this thermal tumbling. Where to Find FAPbI₃ CIF Files fapbi3 cif file
If you are looking to download these files for your research, the most reliable databases are:
Crystallography Open Database (COD): A massive, free repository of crystal structures.
The Cambridge Structural Database (CSD): Excellent for organic-inorganic hybrids.
Materials Project: Provides computed CIFs optimized via DFT.
Published Literature: Key papers (e.g., by Weber or Kanatzidis) often include CIFs as Supplementary Information.
The FAPbI₃ CIF file is more than just a data snippet; it is the structural foundation for the next generation of solar energy. Whether you are stabilizing the α-phase through cation engineering or simulating interface layers, having an accurate CIF file is your first step toward success.
CIF files are used to store and exchange crystallographic data, including the results of X-ray crystallography experiments, in a structured and machine-readable way. These files contain detailed information about the crystal structure of a material, including the positions of atoms within the unit cell, lattice parameters, and other relevant crystallographic data.
The ".cif" extension is commonly associated with this file format.
If you're looking for features related to CIF files or how to work with them, here are a few points:
Software for Viewing and Editing CIF Files: Several software packages can open, view, and edit CIF files. Some examples include:
Content of a CIF File: A CIF file typically includes:
Validation and Checking: It's crucial to validate CIF files for correctness and consistency. Tools and databases, such as the Cambridge Structural Database (CSD) and the Inorganic Crystal Structure Database (ICSD), provide checks and references for crystal structures.
Applications: CIF files are essential in materials science, chemistry, and physics for tasks such as:
If you have a specific CIF file (like one named "fapbi3.cif") and are looking for help with its contents or how to use it, providing more details about the file or what you aim to achieve could help in giving a more precise response.
This is a complete structural definition for FAPbI3FAPbI sub 3
(Formamidinium Lead Iodide) in its most common high-temperature Alpha ( ) phase (Cubic,
This "feature" is formatted as a standard Crystallographic Information File (CIF) that you can copy into software like VESTA, CrystalMaker, or PyMaw. CIF File Content: FAPbI3FAPbI sub 3 (Cubic Phase)
data_FAPbI3_cubic _audit_creation_method 'Hand-generated for Cubic Alpha-Phase' _cell_length_a 6.3620 _cell_length_b 6.3620 _cell_length_c 6.3620 _cell_angle_alpha 90.00 _cell_angle_beta 90.00 _cell_angle_gamma 90.00 _cell_volume 257.49 _symmetry_space_group_name_H-M 'P m -3 m' _symmetry_Int_Tables_number 221 loop_ _atom_site_label _atom_site_type_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Pb1 Pb 0.50000 0.50000 0.50000 1.0 I1 I 0.50000 0.50000 0.00000 1.0 C1 C 0.00000 0.00000 0.00000 1.0 N1 N 0.00000 0.00000 0.18000 0.5 Use code with caution. Copied to clipboard Key Technical Specs Structure: Perovskite ( ABX3cap A cap B cap X sub 3 Lattice Parameter: Å (varies slightly by temperature).
The "Organic" Challenge: In a standard CIF, the FA molecule is often represented by its central Carbon at the origin
. Because the molecule rotates rapidly at room temperature, it is often modeled with disordered Nitrogen sites or as a spherical density. Bandgap: Typically ∼1.48tilde 1.48
eV, making it the "Goldilocks" material for single-junction solar cells. Quick Usage Tips
Visualization: If you open this in VESTA, the FA molecule may look like a single atom at the corners. To see the full molecule, you often have to manually add the Hydrogen positions or use a lower-symmetry space group ( ) if you are running DFT simulations.
Phase Note: If your sample is yellow rather than black, you are likely looking for the Delta ( ) phase (Hexagonal, P63mccap P 6 sub 3 m c ), which is photo-inactive.
Formamidinium lead iodide ( FAPbI3FAPbI sub 3 ) is a cornerstone of modern perovskite photovoltaics, primarily due to its narrow bandgap (
) which allows for broad absorption of the solar spectrum into the near-infrared. For researchers, the Crystallographic Information File (CIF) is the vital blueprint that translates these macroscopic properties into atomic-level spatial coordinates. The Role of the CIF in FAPbI3FAPbI sub 3 A CIF file for FAPbI3FAPbI sub 3 defines the spatial arrangement of the formamidinium ( ) cation, the lead ( Pb2+Pb raised to the 2 plus power ) cation, and the iodide ( I−I raised to the negative power ) anions. It provides critical parameters such as: Space Group: Identifies the symmetry (e.g., for the cubic Lattice Constants: Typically for the room-temperature cubic cell.
Atomic Coordinates: Specific x, y, z positions for each element within the unit cell. Structural Phases and Their Signatures
The usefulness of a specific CIF depends on the "phase" it represents. FAPbI3FAPbI sub 3 Formamidinium lead iodide ( FAPbI3cap F cap A
is notoriously polymorphic, transitioning between several states based on temperature and environment: Common Name Crystal System Space Group Significance -phase Black phase
The "photoactive" phase used in high-efficiency solar cells. -phase Yellow phase P63mccap P 6 sub 3 m c
The thermodynamically stable "non-perovskite" phase at room temperature. -phase Intermediate Tetragonal Occurs as the material cools below -phase Orthorhombic/Trigonal Emerges below with restricted cation motion. Challenges in Modeling: The FA Cation
Unlike the simpler cesium cation, the formamidinium (FA) molecule is a large, non-spherical organic cation. In a standard cubic CIF, the FA molecule often appears disordered because it rotates rapidly within the lead-iodide "cage". This requires researchers to choose between a "time-averaged" CIF (useful for standard XRD refinement) and a "frozen" or relaxed structure (often derived from DFT calculations) for modeling electronic band structures. Strategic Importance FAPbI3.cif - WMD-group/hybrid-perovskites - GitHub
A Crystallographic Information File (CIF) for Formamidinium Lead Iodide ( cap F cap A cap P b cap I sub 3
provides the digital blueprint of its atomic structure, which is essential for X-ray diffraction (XRD) analysis and density functional theory (DFT) simulations Common Crystal Phases of cap F cap A cap P b cap I sub 3 cap F cap A cap P b cap I sub 3
is highly polymorphic, meaning it can exist in several structural arrangements depending on temperature and stability: ) Phase (Black Phase): Structure: High-temperature cubic perovskite ResearchGate Space Group: Commonly assigned to Duke University Lattice Parameter: Approximately ResearchGate
This is the photoactive "champion" phase used in high-efficiency solar cells due to its ideal bandgap AIP Publishing ) Phase (Yellow Phase): Structure: Non-perovskite hexagonal ResearchGate Space Group: cap P 6 sub 3 m c Technische Universität Berlin - TU Berlin Characteristics:
Thermodynamically stable at room temperature but photo-inactive, often appearing as a degradation product of the AIP Publishing Where to Find/Download CIF Files You can obtain verified cap F cap A cap P b cap I sub 3 CIF files from these research databases:
How to run DFT calculations on lower-end PCs? (Free and Fast)
In this case, I downloaded the . cif file for FAPbI3 from here. STEP 2. Open Materials Cloud's QE input Generator and upload the . Saif Ahmed FAPbI3_tetragonal&cubic
Formamidinium lead iodide ( FAPbI3FAPbI sub 3 ) exists in two primary phases at room temperature: the photoactive cubic -phase and the non-perovskite hexagonal
-phase. A Crystallographic Information File (CIF) for this material must accurately define its unit cell parameters, space group, and atomic coordinates. 1. Identify the Phase and Space Group The first step is determining which phase of FAPbI3FAPbI sub 3 you need for your model.
-Phase (Black Phase): This is the high-temperature cubic phase, typically assigned to the (No. 221) space group.
-Phase (Yellow Phase): This is the thermodynamically stable hexagonal phase at room temperature, often assigned to the (No. 194) space group. 2. Set Lattice Parameters
The unit cell dimensions vary significantly between phases and temperatures: Cubic ( ): Single cell length and angles Hexagonal ( ): Lattice parameters are roughly 3. Define Atomic Coordinates Short Guide to CIFs - CCDC
To get a high-quality CIF file for Formamidinium Lead Iodide (FAPbI3), the most reliable method is to pull from established crystallographic databases or community-shared repositories. Top Sources for FAPbI3 CIF Files
The Materials Project: This is the gold standard for DFT-calculated structures. You can find various phases of FAPbI3 (alpha, delta, etc.) by searching for the chemical formula on the Materials Project Explorer.
Crystallography Open Database (COD): A massive collection of experimental crystal structures. Search for "FAPbI3" or the elements to find entries like the cubic -phase or hexagonal -phase at the COD Search Page.
Materials Cloud: Often used by researchers to host specific simulation inputs. For example, some tutorials on Materials Cloud allow you to upload and visualize FAPbI3 structures for Quantum Espresso runs.
ResearchGate/GitHub: Many computational materials science groups host their specific optimized CIFs on GitHub or share them in response to ResearchGate threads regarding perovskite solar cells. Which Phase Do You Need?
When downloading, ensure you select the correct polymorph for your research:
-FAPbI3 (Black phase): The cubic perovskite structure (space group ) used for high-efficiency solar cells.
-FAPbI3 (Yellow phase): The hexagonal non-perovskite phase (space group P63mccap P 6 sub 3 m c
) that is thermodynamically stable at room temperature but photo-inactive.
Pro-Tip: Once you have the file, use VESTA or the Materials Cloud Visualizer to verify the bond lengths and octahedral tilting before running your simulations.
Do you need a specific lattice parameter or a version optimized for a particular DFT functional? Software for Viewing and Editing CIF Files :
How to run DFT calculations on lower-end PCs? (Free and Fast)
Understanding FAPbI₃: The Power of the CIF File in Perovskite Research
In the rapidly evolving world of solar energy research, FAPbI₃ (Formamidinium Lead Iodide) has emerged as a frontrunner. As scientists push the boundaries of perovskite solar cells (PSCs), the ability to understand and manipulate the material's atomic arrangement is crucial. This is where the CIF (Crystallographic Information File) becomes an indispensable tool. What is FAPbI₃?
FAPbI₃ is an organic-inorganic hybrid perovskite. Compared to its predecessor, MAPbI₃ (Methylammonium Lead Iodide), it offers a narrower bandgap (approx. 1.48 eV), which is closer to the ideal Shockley-Queisser limit for single-junction solar cells. This makes it theoretically capable of achieving higher power conversion efficiencies.
However, FAPbI₃ is famous for its phase instability. At room temperature, it tends to transition from the photoactive -phase (black, cubic) to the non-photoactive
-phase (yellow, hexagonal). Understanding this transition starts with the crystal structure. What is a CIF File?
A CIF file (.cif) is the standard format for exchanging crystallographic data. It contains everything needed to reconstruct the 3D lattice of a material, including: Unit cell dimensions (a, b, c) and angles ( Space group symmetry (e.g., Pm3m for cubic FAPbI₃).
Atomic coordinates (x, y, z positions for Formamidinium, Lead, and Iodide). Occupancy and thermal parameters.
For researchers, the CIF file is the "blueprint" used in software like VESTA, Diamond, or Mercury to visualize the crystal and perform DFT (Density Functional Theory) simulations. Key Phases of FAPbI₃ and Their Crystallographic Data
When searching for an FAPbI₃ CIF file, you are likely looking for one of two primary polymorphs: 1. The Alpha Phase ( -FAPbI₃) Symmetry: Cubic (Pm3m) or slightly distorted Tetragonal.
Characteristics: This is the "black phase" desired for solar cells. It features a high-symmetry corner-sharing PbI6cap P b cap I sub 6 octahedral network with the FA⁺ cation in the center.
CIF Utility: Used for simulating light absorption, charge transport, and band structure. 2. The Delta Phase ( -FAPbI₃) Symmetry: Hexagonal (P6₃mc).
Characteristics: The "yellow phase." It consists of face-sharing octahedra, which traps charges and prevents efficient solar energy conversion.
CIF Utility: Essential for researchers studying phase stabilization and how to prevent the degradation of solar panels. Why the FAPbI₃ CIF File is Essential for Research A. Theoretical Modeling (DFT)
Computational chemists use CIF files as the starting point for Density Functional Theory calculations. By importing the FAPbI₃ coordinates, they can predict how adding "additives" (like Cesium or Methylammonium) might stabilize the black phase. B. X-Ray Diffraction (XRD) Analysis
Experimentalists use CIF files to generate reference XRD patterns. When a lab synthesizes a new batch of FAPbI₃, they compare their experimental peaks against the pattern derived from the CIF file to confirm they have successfully created the C. Structural Engineering
Visualizing the CIF file allows researchers to see the "tilt" of the PbI6cap P b cap I sub 6
octahedra. Subtle changes in these angles—often induced by temperature or pressure—drastically affect the material's electronic properties. Where to Find FAPbI₃ CIF Files
If you are looking to download these files for your own research, the most reliable repositories include:
Crystallography Open Database (COD): A massive open-access collection of crystal structures.
The Cambridge Structural Database (CSD): Ideal for organic-inorganic hybrids like FAPbI₃.
Materials Project: Provides computed CIF files along with predicted electronic properties.
Published Literature: Most high-impact papers in journals like Nature Energy or JACS include CIF data in their Supporting Information. Conclusion
The FAPbI₃ CIF file is more than just data; it is the foundational map for the next generation of solar technology. Whether you are a computational physicist or a lab-based materials scientist, mastering the structural nuances contained within these files is the key to unlocking stable, high-efficiency perovskite energy.
If you are training a neural network potential (e.g., MACE, NequIP), you need thousands of distorted CIFs. Use the base fapbi3.cif to generate a supercell, then perturb it.
The most accurate structural parameters often come directly from the seminal papers. The definitive structure was elucidated by researchers like M. Grätzel and colleagues.
FAPbI₃ (formamidinium lead iodide) is a hybrid organic-inorganic perovskite with the chemical formula HC(NH₂)₂PbI₃. It is a promising light-absorbing material in high-efficiency perovskite solar cells (PSCs) due to its optimal band gap (~1.48 eV) and excellent thermal stability compared to its methylammonium counterpart (MAPbI₃).