TY - JOUR
T1 - Globularity-Selected Large Molecules for a New Generation of Multication Perovskites
AU - Gholipour, Somayeh
AU - Ali, Abdollah Morteza
AU - Correa-Baena, Juan Pablo
AU - Turren-Cruz, Silver Hamill
AU - Tajabadi, Fariba
AU - Tress, Wolfgang
AU - Taghavinia, Nima
AU - Grätzel, Michael
AU - Abate, Antonio
AU - De Angelis, Filippo
AU - Gaggioli, Carlo Alberto
AU - Mosconi, Edoardo
AU - Hagfeldt, Anders
AU - Saliba, Michael
N1 - Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2017/10/11
Y1 - 2017/10/11
N2 - Perovskite solar cells (PSCs) use perovskites with an APbX3 structure, where A is a monovalent cation and X is a halide such as Cl, Br, and/or I. Currently, the cations for high-efficiency PSCs are Rb, Cs, methylammonium (MA), and/or formamidinium (FA). Molecules larger than FA, such as ethylammonium (EA), guanidinium (GA), and imidazolium (IA), are usually incompatible with photoactive “black”-phase perovskites. Here, novel molecular descriptors for larger molecular cations are introduced using a “globularity factor”, i.e., the discrepancy of the molecular shape and an ideal sphere. These cationic radii differ significantly from previous reports, showing that especially ethylammonium (EA) is only slightly larger than FA. This makes EA a suitable candidate for multication 3D perovskites that have potential for unexpected and beneficial properties (suppressing halide segregation, stability). This approach is tested experimentally showing that surprisingly large quantities of EA get incorporated, in contrast to most previous reports where only small quantities of larger molecular cations can be tolerated as “additives”. MA/EA perovskites are characterized experimentally with a band gap ranging from 1.59 to 2.78 eV, demonstrating some of the most blue-shifted PSCs reported to date. Furthermore, one of the compositions, MA0.5EA0.5PbBr3, shows an open circuit voltage of 1.58 V, which is the highest to date with a conventional PSC architecture.
AB - Perovskite solar cells (PSCs) use perovskites with an APbX3 structure, where A is a monovalent cation and X is a halide such as Cl, Br, and/or I. Currently, the cations for high-efficiency PSCs are Rb, Cs, methylammonium (MA), and/or formamidinium (FA). Molecules larger than FA, such as ethylammonium (EA), guanidinium (GA), and imidazolium (IA), are usually incompatible with photoactive “black”-phase perovskites. Here, novel molecular descriptors for larger molecular cations are introduced using a “globularity factor”, i.e., the discrepancy of the molecular shape and an ideal sphere. These cationic radii differ significantly from previous reports, showing that especially ethylammonium (EA) is only slightly larger than FA. This makes EA a suitable candidate for multication 3D perovskites that have potential for unexpected and beneficial properties (suppressing halide segregation, stability). This approach is tested experimentally showing that surprisingly large quantities of EA get incorporated, in contrast to most previous reports where only small quantities of larger molecular cations can be tolerated as “additives”. MA/EA perovskites are characterized experimentally with a band gap ranging from 1.59 to 2.78 eV, demonstrating some of the most blue-shifted PSCs reported to date. Furthermore, one of the compositions, MA0.5EA0.5PbBr3, shows an open circuit voltage of 1.58 V, which is the highest to date with a conventional PSC architecture.
KW - light-emitting devices
KW - perovskite solar cells
KW - quasi-3D cations
KW - wide band-gap semiconductors
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U2 - 10.1002/adma.201702005
DO - 10.1002/adma.201702005
M3 - Article
C2 - 28833614
AN - SCOPUS:85030657028
SN - 0935-9648
VL - 29
JO - Advanced Materials
JF - Advanced Materials
IS - 38
M1 - 1702005
ER -