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Stabilizing Surface Passivation Enables Stable Operation of Colloidal Quantum Dot Photovoltaic Devices at Maximum Power Point in an Air Ambient
Author(s) -
Choi Jongmin,
Choi MinJae,
Kim Junghwan,
Dinic Filip,
Todorovic Petar,
Sun Bin,
Wei Mingyang,
Baek SeWoong,
Hoogland Sjoerd,
García de Arquer F. Pelayo,
Voznyy Oleksandr,
Sargent Edward H.
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201906497
Subject(s) - passivation , materials science , photovoltaic system , quantum dot , optoelectronics , nanotechnology , energy conversion efficiency , inert gas , layer (electronics) , composite material , electrical engineering , engineering
Colloidal quantum dots (CQDs) are promising materials for photovoltaic (PV) applications owing to their size‐tunable bandgap and solution processing. However, reports on CQD PV stability have been limited so far to storage in the dark; or operation illuminated, but under an inert atmosphere. CQD PV devices that are stable under continuous operation in air have yet to be demonstrated—a limitation that is shown here to arise due to rapid oxidation of both CQDs and surface passivation. Here, a stable CQD PV device under continuous operation in air is demonstrated by introducing additional potassium iodide (KI) on the CQD surface that acts as a shielding layer and thus stands in the way of oxidation of the CQD surface. The devices (unencapsulated) retain >80% of their initial efficiency following 300 h of continuous operation in air, whereas CQD PV devices without KI lose the amount of performance within just 21 h. KI shielding also provides improved surface passivation and, as a result, a higher power conversion efficiency (PCE) of 12.6% compared with 11.4% for control devices.