Ferroelectricity in a semiconducting all-inorganic halide perovskite

Journal Article · 09 February 2022 · Science Advances

DOI: https://doi.org/10.1126/sciadv.abj5881 · OSTI ID:1846755

Zhang, Ye ^[1]; Parsonnet, Eric ^[1]; Fernandez, Abel ^[1]; Griffin, Sinéad M. ^[2]; Huyan, Huaixun ^[3]; Lin, Chung-Kuan ^[4]; Lei, Teng ^[1]; Jin, Jianbo ^[1]; Barnard, Edward S. ^[2]; Raja, Archana ^[2]; Behera, Piush ^[4]; Pan, Xiaoqing ^[3]; Ramesh, Ramamoorthy ^[4]; Yang, Peidong ^[5]

---

1. Univ. of California, Berkeley, CA (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
3. Univ. of California, Irvine, CA (United States)
4. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
5. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kavli Energy NanoScience Inst., Berkeley, CA (United States)

Ferroelectric semiconductors are rare materials with both spontaneous polarizations and visible light absorptions that are promising for designing functional photoferroelectrics, such as optical switches and ferroelectric photovoltaics. The emerging halide perovskites with remarkable semiconducting properties also have the potential of being ferroelectric, yet the evidence of robust ferroelectricity in the typical three-dimensional hybrid halide perovskites has been elusive. Here, we report on the investigation of ferroelectricity in all-inorganic halide perovskites, CsGeX₃, with bandgaps of 1.6 to 3.3 eV. Their ferroelectricity originates from the lone pair stereochemical activity in Ge (II) that promotes the ion displacement. This gives rise to their spontaneous polarizations of ~10 to 20 μC/cm², evidenced by both ab initio calculations and key experiments including atomic-level ionic displacement vector mapping and ferroelectric hysteresis loop measurement. Furthermore, characteristic ferroelectric domain patterns on the well-defined CsGeBr₃ nanoplates are imaged with both piezo-response force microscopy and nonlinear optical microscopic method.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1846755
• Journal Information: Science Advances, Vol. 8, Issue 6; ISSN 2375-2548
• Publisher: AAASCopyright Statement
• Country of Publication: United States
• Language: English