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Title: Efficient Charge Extraction and Slow Recombination in Organic-Inorganic Perovskites Capped with Semiconducting Single-Walled Carbon Nanotubes

Metal-halide based perovskite solar cells have rapidly emerged as a promising alternative to traditional inorganic and thin-film photovoltaics. Although charge transport layers are used on either side of perovskite absorber layers to extract photogenerated electrons and holes, the time scales for charge extraction and recombination are poorly understood. Ideal charge transport layers should facilitate large discrepancies between charge extraction and recombination rates. Here, we demonstrate that highly enriched semiconducting single-walled carbon nanotube (SWCNT) films enable rapid (sub-picosecond) hole extraction from a prototypical perovskite absorber layer and extremely slow back-transfer and recombination (hundreds of microseconds). The energetically narrow and distinct spectroscopic signatures for charges within these SWCNT thin films enables the unambiguous temporal tracking of each charge carrier with time-resolved spectroscopies covering many decades of time. The efficient hole extraction by the SWCNT layer also improves electron extraction by the compact titanium dioxide electron transport layer, which should reduce charge accumulation at each critical interface. Finally, we demonstrate that the use of thin interface layers of semiconducting single-walled carbon nanotubes between the perovskite absorber layer and a prototypical hole transport layer improves device efficiency and stability, and reduces hysteresis.
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Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1754-5692
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Energy & Environmental Science; Journal Volume: 9; Journal Issue: 4; Related Information: Energy and Environmental Science
Royal Society of Chemistry
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
14 SOLAR ENERGY; 77 NANOSCIENCE AND NANOTECHNOLOGY; semiconducting single-walled carbon nanotube (SWCNT); rapid hole extraction; perovskite absorber layer; back-transfer; recombination