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Understanding the Role of Cesium and Rubidium Additives in Perovskite Solar Cells: Trap States, Charge Transport, and Recombination
Author(s) -
Hu Yinghong,
Hutter Eline M.,
Rieder Philipp,
Grill Irene,
Hanisch Jonas,
Aygüler Meltem F.,
Hufnagel Alexander G.,
Handloser Matthias,
Bein Thomas,
Hartschuh Achim,
Tvingstedt Kristofer,
Dyakonov Vladimir,
Baumann Andreas,
Savenije Tom J.,
Petrus Michiel L.,
Docampo Pablo
Publication year - 2018
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.201703057
Subject(s) - rubidium , perovskite (structure) , caesium , materials science , halide , hysteresis , charge carrier , solar cell , trapping , perovskite solar cell , chemical physics , optoelectronics , analytical chemistry (journal) , inorganic chemistry , chemistry , potassium , crystallography , condensed matter physics , physics , chromatography , metallurgy , ecology , biology
Adding cesium (Cs) and rubidium (Rb) cations to FA 0.83 MA 0.17 Pb(I 0.83 Br 0.17 ) 3 hybrid lead halide perovskites results in a remarkable improvement in solar cell performance, but the origin of the enhancement has not been fully understood yet. In this work, time‐of‐flight, time‐resolved microwave conductivity, and thermally stimulated current measurements are performed to elucidate the impact of the inorganic cation additives on the trap landscape and charge transport properties within perovskite solar cells. These complementary techniques allow for the assessment of both local features within the perovskite crystals and macroscopic properties of films and full devices. Strikingly, Cs‐incorporation is shown to reduce the trap density and charge recombination rates in the perovskite layer. This is consistent with the significant improvements in the open‐circuit voltage and fill factor of Cs‐containing devices. By comparison, Rb‐addition results in an increased charge carrier mobility, which is accompanied by a minor increase in device efficiency and reduced current–voltage hysteresis. By mixing Cs and Rb in quadruple cation (Cs‐Rb‐FA‐MA) perovskites, the advantages of both inorganic cations can be combined. This study provides valuable insights into the role of these additives in multiple‐cation perovskite solar cells, which are essential for the design of high‐performance devices.