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Towards Efficient Integrated Perovskite/Organic Bulk Heterojunction Solar Cells: Interfacial Energetic Requirement to Reduce Charge Carrier Recombination Losses
Author(s) -
Daboczi Matyas,
Kim Jinhyun,
Lee Jinho,
Kang Hongkyu,
Hamilton Iain,
Lin ChiehTing,
Dimitrov Stoichko D.,
McLachlan Martyn A.,
Lee Kwanghee,
Durrant James R.,
Kim JiSeon
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202001482
Subject(s) - perovskite (structure) , photoactive layer , materials science , energy conversion efficiency , charge carrier , heterojunction , optoelectronics , organic solar cell , carrier lifetime , polymer solar cell , perovskite solar cell , hybrid solar cell , organic semiconductor , active layer , layer (electronics) , nanotechnology , chemical engineering , polymer , silicon , composite material , thin film transistor , engineering
Integrated perovskite/organic bulk heterojunction (BHJ) solar cells have the potential to enhance the efficiency of perovskite solar cells by a simple one‐step deposition of an organic BHJ blend photoactive layer on top of the perovskite absorber. It is found that inverted structure integrated solar cells show significantly increased short‐circuit current ( J sc ) gained from the complementary absorption of the organic BHJ layer compared to the reference perovskite‐only devices. However, this increase in J sc is not directly reflected as an increase in power conversion efficiency of the devices due to a loss of fill factor. Herein, the origin of this efficiency loss is investigated. It is found that a significant energetic barrier (≈250 meV) exists at the perovskite/organic BHJ interface. This interfacial barrier prevents efficient transport of photogenerated charge carriers (holes) from the BHJ layer to the perovskite layer, leading to charge accumulation at the perovskite/BHJ interface. Such accumulation is found to cause undesirable recombination of charge carriers, lowering surface photovoltage of the photoactive layers and device efficiency via fill factor loss. The results highlight a critical role of the interfacial energetics in such integrated cells and provide useful guidelines for photoactive materials (both perovskite and organic semiconductors) required for high‐performance devices.