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Organic Salts as a Route to Energy Level Control in Low Bandgap, High Open‐Circuit Voltage Organic and Transparent Solar Cells that Approach the Excitonic Voltage Limit
Author(s) -
SuddardBangsund John,
Traverse Christopher J.,
Young Margaret,
Patrick Tyler J.,
Zhao Yimu,
Lunt Richard R.
Publication year - 2016
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.201501659
Subject(s) - open circuit voltage , materials science , organic solar cell , photovoltaics , optoelectronics , voltage , band gap , acceptor , exciton , nanotechnology , photovoltaic system , electrical engineering , polymer , physics , condensed matter physics , composite material , engineering , quantum mechanics
A new series of organic salts with selective near‐infrared (NIR) harvesting to 950 nm is reported, and anion selection and blending is demonstrated to allow for fine tuning of the open‐circuit voltage. Extending photoresponse deeper into the NIR is a significant challenge facing small molecule organic photovoltaics, and recent demonstrations have been limited by open‐circuit voltages much lower than the theoretical and practical limits. This work presents molecular design strategies that enable facile tuning of energy level alignment and open‐circuit voltages in organic salt‐based photovoltaics. Anions are also shown to have a strong influence on exciton diffusion length. These insights provide a clear route toward achieving high efficiency transparent and panchromatic photovoltaics, and open up design opportunities to rapidly tailor molecules for new donor–acceptor systems.