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Ionic Reactivity at Contacts and Aging of Methylammonium Lead Triiodide Perovskite Solar Cells
Author(s) -
Carrillo Jordi,
Guerrero Antonio,
Rahimnejad Sara,
Almora Osbel,
Zarazua Issac,
MasMarza Elena,
Bisquert Juan,
GarciaBelmonte Germà
Publication year - 2016
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201502246
Subject(s) - triiodide , materials science , perovskite (structure) , solar cell , ionic bonding , reactivity (psychology) , perovskite solar cell , halide , energy conversion efficiency , chemical physics , photovoltaic system , ion , chemical engineering , nanotechnology , optoelectronics , inorganic chemistry , electrolyte , chemistry , electrode , dye sensitized solar cell , organic chemistry , medicine , ecology , alternative medicine , pathology , biology , engineering
Hybrid lead halide perovskites have reached very large solar to electricity power conversion efficiencies, in some cases exceeding 20%. The most extensively used perovskite‐based solar cell configuration comprises CH 3 NH 3 PbI 3 (MAPbI 3 ) in combination with electron (TiO 2 ) and hole 2,2′,7,7′‐tetrakis( N , N ‐di‐ p ‐methoxyphenylamine)‐9,9‐ spiro ‐bifluorene ( spiro ‐OMeTAD) selective contacts. The recognition that the solar cell performance is heavily affected by time scale of the measurement and preconditioning procedures has raised many concerns about the stability of the device and reliability for long‐time operation. Mechanisms at contacts originate observable current–voltage distortions. Two types of reactivity sources have been identified here: (i) weak Ti–I–Pb bonds that facilitate interfacial accommodation of moving iodine ions. This interaction produces a highly reversible capacitive current originated at the TiO 2 /MAPbI 3 interface, and it does not alter steady‐state photovoltaic features. (ii) An irreversible redox peak only observable after positive poling at slow scan rates. It corresponds to the chemical reaction between spiro ‐OMeTAD + and migrating I − which progressively reduces the hole transporting material conductivity and deteriorates solar cell performance.