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Co‐Evaporated Formamidinium Lead Iodide Based Perovskites with 1000 h Constant Stability for Fully Textured Monolithic Perovskite/Silicon Tandem Solar Cells
Author(s) -
Roß Marcel,
Severin Stefanie,
Stutz Marvin Björn,
Wagner Philipp,
Köbler Hans,
FavinLévêque Martin,
AlAshouri Amran,
Korb Paul,
Tockhorn Philipp,
Abate Antonio,
Stannowski Bernd,
Rech Bernd,
Albrecht Steve
Publication year - 2021
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.202101460
Subject(s) - formamidinium , perovskite (structure) , materials science , iodide , tandem , evaporation , silicon , phase (matter) , chemical engineering , optoelectronics , inorganic chemistry , composite material , chemistry , organic chemistry , physics , engineering , thermodynamics
Formamidinium iodide (FAI) based perovskite absorbers have been shown to be ideal candidates for highly efficient and operationally stable perovskite solar cells (PSC). A major challenge for formamidinium lead iodide (FAPbI 3 ) is to suppress the phase transition from the photoactive black phase into yellow nonperovskite δ‐phase. Several approaches to stabilize the black phase have been developed for solution‐based perovskites, whereas so far, vacuum‐deposited FAPbI 3 has rarely been reported. This study demonstrates the preparation of FAPbI 3 by co‐evaporation and discusses the influence of the subjacent hole transporting layer (HTL) on its phase stability. By using FAI excess in the evaporation process in combination with phosphonic acids groups from the HTL, the black perovskite phase is stabilized at room temperature. Further addition of 32–59% methylammonium iodide (MAI) during the co‐evaporation process leads to good absorption properties and high PSC efficiencies of 20.4%. In addition, excellent stability is achieved for optimized MAI to FAI ratios, maintaining 100% of the initial PSC performance after 1000 h under constant operation. This highly stable perovskite composition enables the first monolithic fully textured perovskite/silicon tandem solar cells with co‐evaporated perovskite absorbers. Due to the conformally covered pyramid texture, these tandem cells show minimal reflection losses and reach an efficiency of 24.6%.