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Title: Characterizing and Improving the Thermal Stability of Organic Photovoltaics Based on Halogen-Rich Non-Fullerene Acceptors

Journal Article · · ACS Applied Materials and Interfaces

In this work, the thermal stability of inverted, halogen-rich non-fullerene acceptor (NFA)-based organic photovoltaics (OPVs) with MoOx as the hole transporting layer is studied at temperatures up to 80°C. Over time, the power conversion efficiency shows a “check-mark” shaped thermal aging pattern, featuring an early decrease, followed by a long-term recovery. A high Cl concentration at the BHJ/MoOx interface in the thermally aged device is found using energy dispersive X-ray spectroscopy. X-Ray photoelectron spectroscopy shows that the MoOx is chlorinated after thermal aging. With bulk quantum efficiency analysis, we propose an explanation to the check-mark shaped pattern. Inserting a thin C70 layer between the BHJ and MoOx suppresses the thermal degradation mechanisms, resulting in 3 orders of magnitude increase in device lifetime at 80°C.

Research Organization:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office; US Department of the Navy, Office of Naval Research (ONR)
Grant/Contract Number:
EE0008561; N00014-17-1-2211
OSTI ID:
1842483
Journal Information:
ACS Applied Materials and Interfaces, Vol. 14, Issue 4; ISSN 1944-8244
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English

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