TY - JOUR
T1 - Incorporated guanidinium expands the CH3NH3PbI3 lattice and enhances photovoltaic performance
AU - Gao, Lili
AU - Li, Xiaotong
AU - Liu, Yan
AU - Fang, Junjie
AU - Huang, Sheng
AU - Spanopoulos, Ioannis
AU - Li, Xiaolei
AU - Wang, Yao
AU - Chen, Lin
AU - Yang, Guanjun
AU - Kanatzidis, Mercouri G.
N1 - Funding Information:
The work at Northwestern University was supported by a grant from ONR (N00014-20-1-2725). The work was supported by the National Key R&D Program of China (no. 2019YFB1503200) and the National Program for Support of Top-notch Young Professionals. L.G. gratefully acknowledges financial support from the Joint Educational Ph.D. Program of Chinese Scholarship Council (CSC).
PY - 2020/9/30
Y1 - 2020/9/30
N2 - Guanidinium (GA) has been widely used as an additive in solar cells for enhanced performance. However, the size of the guanidinium cation is too large to be incorporated in the cage of the perovskite structure. Instead, GA forms a variety of structures with lead iodide, where its role in the perovskite crystal as well as solar cell devices is unclear. In this study, we demonstrate that GA can be incorporated into the structure of MAPbI3 as (GA)x(MA)1−xPbI3. From single-crystal X-ray crystallographic refinement, we observe lattice expansion and Pb−I bond elongation with GA incorporation similar to exerting “negative pressure”, which weakens orbital overlap and widens the band gap from 1.49 to 1.53 eV. We find that the highest percentage of GA that can be incorporated into the 3D MAPbI3 structure is 5.26%, as confirmed by nuclear magnetic resonance. The alloyed (GA)x(MA)1−xPbI3 exhibits increased PL lifetimes from 154.4 to 266.3 ns after GA incorporation while the Voc of (GA)x(MA)1−xPbI3 devices enlarges from 1.05 to 1.11 V. High efficiencies in solar cell devices up to 20.38% with a Jsc of 23.55 mA cm−2, Voc of 1.11 V, and FF of 0.78 have been achieved, with stable photovoltaic performance for 900 h in air.
AB - Guanidinium (GA) has been widely used as an additive in solar cells for enhanced performance. However, the size of the guanidinium cation is too large to be incorporated in the cage of the perovskite structure. Instead, GA forms a variety of structures with lead iodide, where its role in the perovskite crystal as well as solar cell devices is unclear. In this study, we demonstrate that GA can be incorporated into the structure of MAPbI3 as (GA)x(MA)1−xPbI3. From single-crystal X-ray crystallographic refinement, we observe lattice expansion and Pb−I bond elongation with GA incorporation similar to exerting “negative pressure”, which weakens orbital overlap and widens the band gap from 1.49 to 1.53 eV. We find that the highest percentage of GA that can be incorporated into the 3D MAPbI3 structure is 5.26%, as confirmed by nuclear magnetic resonance. The alloyed (GA)x(MA)1−xPbI3 exhibits increased PL lifetimes from 154.4 to 266.3 ns after GA incorporation while the Voc of (GA)x(MA)1−xPbI3 devices enlarges from 1.05 to 1.11 V. High efficiencies in solar cell devices up to 20.38% with a Jsc of 23.55 mA cm−2, Voc of 1.11 V, and FF of 0.78 have been achieved, with stable photovoltaic performance for 900 h in air.
KW - 3D halide perovskites
KW - Expanded lattice
KW - Guanidinium incorporation
KW - Photovoltaic performance
KW - Stability
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U2 - 10.1021/acsami.0c14925
DO - 10.1021/acsami.0c14925
M3 - Article
C2 - 32869968
AN - SCOPUS:85092682274
VL - 12
SP - 43885
EP - 43891
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 39
ER -