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25.1% High‐Efficiency Monolithic Perovskite Silicon Tandem Solar Cell with a High Bandgap Perovskite Absorber
Author(s) -
Schulze Patricia S. C.,
Bett Alexander J.,
Bivour Martin,
Caprioglio Pietro,
Gerspacher Fabian M.,
Kabaklı Özde Ş.,
Richter Armin,
Stolterfoht Martin,
Zhang Qinxin,
Neher Dieter,
Hermle Martin,
Hillebrecht Harald,
Glunz Stefan W.,
Goldschmidt Jan Christoph
Publication year - 2020
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.202000152
Subject(s) - tandem , materials science , perovskite (structure) , band gap , optoelectronics , quantum efficiency , passivation , energy conversion efficiency , silicon , heterojunction , photoluminescence , perovskite solar cell , nanotechnology , chemical engineering , composite material , layer (electronics) , engineering
Monolithic perovskite silicon tandem solar cells can overcome the theoretical efficiency limit of silicon solar cells. This requires an optimum bandgap, high quantum efficiency, and high stability of the perovskite. Herein, a silicon heterojunction bottom cell is combined with a perovskite top cell, with an optimum bandgap of 1.68 eV in planar p–i–n tandem configuration. A methylammonium‐free FA 0.75 Cs 0.25 Pb(I 0.8 Br 0.2 ) 3 perovskite with high Cs content is investigated for improved stability. A 10% molarity increase to 1.1 m of the perovskite precursor solution results in ≈75 nm thicker absorber layers and 0.7 mA cm −2 higher short‐circuit current density. With the optimized absorber, tandem devices reach a high fill factor of 80% and up to 25.1% certified efficiency. The unencapsulated tandem device shows an efficiency improvement of 2.3% (absolute) over 5 months, showing the robustness of the absorber against degradation. Moreover, a photoluminescence quantum yield analysis reveals that with adapted charge transport materials and surface passivation, along with improved antireflection measures, the high bandgap perovskite absorber has the potential for 30% tandem efficiency in the near future.