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Insights about the Absence of Rb Cation from the 3D Perovskite Lattice: Effect on the Structural, Morphological, and Photophysical Properties and Photovoltaic Performance
Author(s) -
Uchida Ryusuke,
Binet Silvia,
Arora Neha,
Jacopin Gwenole,
Alotaibi Mohammad Hayal,
Taubert Andreas,
Zakeeruddin Shaik M.,
Dar M. Ibrahim,
Graetzel Michael
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201802033
Subject(s) - formamidinium , perovskite (structure) , tetragonal crystal system , photoluminescence , orthorhombic crystal system , materials science , halide , nucleation , photovoltaics , chemical physics , crystallography , density functional theory , photovoltaic system , chemical engineering , chemistry , crystal structure , inorganic chemistry , computational chemistry , optoelectronics , organic chemistry , engineering , biology , ecology
Efficiencies >20% are obtained from the perovskite solar cells (PSCs) employing Cs + and Rb + based perovskite compositions; therefore, it is important to understand the effect of these inorganic cations specifically Rb + on the properties of perovskite structures. Here the influence of Cs + and Rb + is elucidated on the structural, morphological, and photophysical properties of perovskite structures and the photovoltaic performances of resulting PSCs. Structural, photoluminescence (PL), and external quantum efficiency studies establish the incorporation of Cs + ( x < 10%) but amply rule out the possibility of Rb‐incorporation into the MAPbI 3 (MA = CH 3 NH 3 + ) lattice. Moreover, morphological studies and time‐resolved PL show that both Cs + and Rb + detrimentally affect the surface coverage of MAPbI 3 layers and charge‐carrier dynamics, respectively, by influencing nucleation density and by inducing nonradiative recombination. In addition, differential scanning calorimetry shows that the transition from orthorhombic to tetragonal phase occurring around 160 K requires more thermal energy for the Cs‐containing MAPbI 3 systems compared to the pristine MAPbI 3 . Investigation including mixed halide (I/Br) and mixed cation A‐cation based compositions further confirms the absence of Rb + from the 3D‐perovskite lattice. The fundamental insights gained through this work will be of great significance to further understand highly promising perovskite compositions.