Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells.

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Abdi-Jalebi, Mojtaba 
Dar, M Ibrahim 
Senanayak, Satyaprasad P 
Grätzel, Michael 

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical properties. The possibility of doping was investigated by adding monovalent cation halides with similar ionic radii to Pb2+, including Cu+, Na+, and Ag+. A shift in the Fermi level and a remarkable decrease of sub-bandgap optical absorption, along with a lower energetic disorder in the perovskite, was achieved. An order-of-magnitude enhancement in the bulk hole mobility and a significant reduction of transport activation energy within an additive-based perovskite device was attained. The confluence of the aforementioned improved properties in the presence of these cations led to an enhancement in the photovoltaic parameters of the perovskite solar cell. An increase of 70 mV in open circuit voltage for AgI and a 2 mA/cm2 improvement in photocurrent density for NaI- and CuBr-based solar cells were achieved compared to the pristine device. Our work paves the way for further improvements in the optoelectronic quality of CH3NH3PbI3 perovskite and subsequent devices. It highlights a new avenue for investigations on the role of dopant impurities in crystallization and controls the electronic defect density in perovskite structures.

Calcium Compounds, Cations, Monovalent, Cell Count, Crystallization, Electric Power Supplies, Iodides, Lead, Methylamines, Oxides, Solar Energy, Time Factors, Titanium
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Journal of Visualized Experiments
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MYJoVE Corporation
M. Abdi-Jalebi thanks Nava Technology Limited for a PhD scholarship. M.I. Dar and M.Grätzel thank the King Abdulaziz City for Science and Technology (KACST) and the Swiss National Science Foundation (SNSF) for financial support.