Effect of High Dipole Moment Cation on Layered 2D Organic–Inorganic Halide Perovskite Solar Cells. Issue 5 (11th December 2018)

• Record Type: Journal Article
• Authors: Tan, Shunquan; Zhou, Ning; Chen, Yihua; Li, Liang; Liu, Guilin; Liu, Pengfei; Zhu, Cheng; Lu, Jiuzhou; Sun, Wentao; Chen, Qi; Zhou, Huanping
• Is Part Of: Advanced energy materials. Volume 9:Issue 5(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-12-11
• Subjects: charge generation -- charge recombination -- exciton binding energy -- high dipole moment -- layered 2D perovskites; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201803024
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Layered 2D organic–inorganic hybrid perovskite is appearing as a rising star in the photovoltaic field, thanks to its superior moisture resistance by the organic spacer cations. Unfortunately, these cations lead to high exciton binding energy in the 2D perovskites, which suffers from lower efficiency in the devices. It thus requires a clear criterion to select/design appropriate organic spacer cations to improve the device efficiency based on this class of materials. Here, 2, 2, 2‐trifluoroethylamine (F3 EA + ) is introduced to combine with butylammonium (BA + ) cations as mixed spacers. While BA + enables self‐assembly of 2D perovskite crystals by van der Waals interaction, the introduction of F3 EA + spacers with a high dipole moment suppress nonradiative recombination and promote separation of photogenerated electron–hole pairs by taking the advantage of electronegativity of fluorine. The resultant solar cells based on [(BA)1– x (F3 EA) x ]2 (MA)3 Pb4 I13 exhibit substantially increased open circuit voltage and fill factor compared with that of (BA)2 (MA)3 Pb4 I13 . The champion [(BA)0.94 (F3 EA)0.06 ]2 (MA)3 Pb4 I13 solar cell yields a power conversion efficiency of 12.51%, which is among the best performances so far. These findings suggest an effective strategy to design organic spacer cations in layered perovskite for solar cells and other optoelectronic applications. Abstract : A high dipole moment cation as a large organic spacer reduces the dielectric confinement effect and hence promotes separation of photogenerated electron–hole pairs in layered 2D perovskite materials, which leads to more efficient and stable perovskite solar cells.