Open AccessThe Relation of Phase‐Transition Effects and Thermal Stability of Planar Perovskite Solar Cells
Author(s) -
Qin Chuanjiang,
Matsushima Toshinori,
Klotz Dino,
Fujihara Takashi,
Adachi Chihaya
Publication year - 2019
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201801079
Subject(s) - materials science , perovskite (structure) , thermogravimetric analysis , thermal stability , phase transition , dielectric spectroscopy , tetragonal crystal system , phase (matter) , energy conversion efficiency , temperature cycling , chemical engineering , thermal , analytical chemistry (journal) , optoelectronics , chemistry , electrode , thermodynamics , electrochemistry , organic chemistry , physics , engineering
A power conversion efficiency of over 20% has been achieved in CH 3 NH 3 PbI 3 ‐based perovskite solar cells (PSC), however, low thermal stability associated with the presence of a phase transition between tetragonal and cubic structures near room temperature is a major issue that must be overcome for future practical applications. Here, the influence of the phase transition on the thermal stability of PSCs is investigated in detail by comparing four kinds of perovskite films with different compositions of halogen atoms and organic components. Thermally stimulated current measurements reveal that a large number of carrier traps are generated in solar cells with the perovskite CH 3 NH 3 PbI 3 as a light absorber after operation at 85 °C, which is higher than the phase‐transition temperature. Electrochemical impedance spectroscopy measurements further exclude effects of a possible morphology change on the formation of carrier traps. These carrier traps are detrimental to the thermal stability. The thermogravimetric analysis does not show a decomposition for any of the materials in the temperature range relevant for operation. The perovskite alloys do not have this phase transition, resulting in effectively suppressed formation of carrier traps. PSCs with improved thermal stability under the standard thermal cycling test are demonstrated.