Fapbi3 Cif File May 2026
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. fapbi3 cif file
-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 Formamidinium lead iodide ( FAPbI3FAPbI sub 3 )
Title: Structural Elucidation and Symmetry-Composition Relations in Formamidinium Lead Triiodide (FAPbI$_3$): A Deep Dive into the $Fm\bar3m$ to $Pm\bar3m$ Transition via Powder Diffraction Analysis
Abstract
Formamidinium lead triiodide (HC(NH$_2$)$_2$PbI$_3$ or FAPbI$_3$) represents the forefront of next-generation photovoltaic materials, offering a reduced bandgap closer to the Shockley-Queisser optimum compared to its methylammonium counterpart. However, the structural instability of the photoactive perovskite phase ($\alpha$-phase) remains a critical bottleneck. This paper provides a comprehensive crystallographic analysis of the FAPbI$_3$ Crystallographic Information File (CIF), focusing on the temperature-dependent phase transitions from the cubic $Fm\bar3m$ (or pseudo-cubic $Pm\bar3m$) structure to the non-perovskite hexagonal $P6_3mc$ phase. Through simulated Rietveld refinement and group-subgroup analysis, we deconvolute the orientational disorder of the formamidinium cation and its impact on the lattice parameters, offering a definitive guide for interpreting experimental diffraction data.
What is FAPBI3 CIF?
FAPBI3 CIF refers to the Crystallographic Information File (CIF) for the compound FAPBI3, a perovskite-like material with formula often written as FAPbI3 (formamidinium lead iodide). FAPbI3 is a widely studied hybrid organic–inorganic perovskite notable for its optoelectronic properties and use in high-efficiency perovskite solar cells and light-emitting devices. What is FAPBI3 CIF
Problem 1: The Wrong Lattice Constant
- Issue: A CIF from 2013 gives
a = 6.36 Å. A CIF from 2024, after strain engineering, givesa = 6.34 Å. - Solution: For DFT bandgap calculation, use experimental lattice parameters from the specific paper you are benchmarking against (e.g., 6.362 Å at 293K). Do not mix-and-match.
Defects and Vacancies
A pristine CIF lacks defects. To study iodine vacancies (V_I), open the CIF in VESTA, delete an iodine atom, and save a new CIF (now with partial occupancy). Warning: Charge neutrality must be maintained in DFT.
Method B: The Materials Project
This is a powerful tool for computational chemists.
- Go to Materials Project.
- Search for "Formamidinium lead iodide".
- You will find entries such as
mp-1009070(this ID changes, always search by name). - The Materials Project allows you to download the structure directly as a CIF file.