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Modulation Effect Generated by A Cations in Hybrid A2BB'X6 Double Halogen Perovskite Materials.
Ruotong Yin1, Gan Yu1, Wei-Yan Cong1
1School of Space Science and Physics, Shandong University, Weihai 264209, China.
ACS Applied Materials & Interfaces
|September 15, 2020
Summary
We studied Cs2AgBiBr6 and hybrid organic-inorganic (MA)2AgBiBr6 double perovskites. Organic cation alignment in (MA)2AgBiBr6 causes lattice distortion, slightly reducing the band gap compared to Cs2AgBiBr6.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Crystallography
Background:
- Double perovskites A2BB'X6, encompassing inorganic and hybrid organic-inorganic types, offer significant application potential.
- The A-site cation's role in double perovskites differs fundamentally from standard perovskites.
- Understanding these differences is crucial for designing advanced materials.
Purpose of the Study:
- To systematically analyze the geometric and electronic structures of Cs2AgBiBr6 and (MA)2AgBiBr6 (MA = CH3NH3) double perovskites.
- To elucidate the influence of A-site cations on the structural and electronic properties of double perovskites.
- To clarify the role of organic cations in hybrid organic-inorganic double perovskites.
Main Methods:
- Computational analysis of geometric structures.
- Investigation of electronic band structures.
- Comparative study of Cs2AgBiBr6 and (MA)2AgBiBr6.
Main Results:
- Cs2AgBiBr6 adopts a standard cubic double perovskite lattice.
- In (MA)2AgBiBr6, MA molecules align along the [110] direction, inducing lattice distortion.
- (MA)2AgBiBr6 exhibits a slightly smaller band gap than Cs2AgBiBr6 due to dispersed bonding states and band expansion.
Conclusions:
- A-site cation choice significantly impacts double perovskite structure and electronic properties.
- Lattice distortion in hybrid organic-inorganic double perovskites, while not altering band edge composition, influences band gap through complex bonding interactions.
- Clarifying the role of A cations is key to developing high-performance double perovskites for diverse applications.
Keywords:
(MA)2AgBiBr6Cs2AgBiBr6band gap modulationbonding effectdouble perovskitesolar cell materialMore Related Videos
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