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Energy Level Alignment and Sub‐Bandgap Charge Generation in Polymer:Fullerene Bulk Heterojunction Solar Cells
Author(s) -
Tsang SaiWing,
Chen Song,
So Franky
Publication year - 2013
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.201204495
Subject(s) - materials science , band gap , optoelectronics , heterojunction , fullerene , polymer solar cell , exciton , organic solar cell , solar cell , charge (physics) , electric field , hybrid solar cell , photovoltaic system , polymer , absorption (acoustics) , condensed matter physics , physics , electrical engineering , engineering , quantum mechanics , composite material
Using charge modulated electroabsorption spectroscopy (CMEAS), for the first time, the energy level alignment of a polymer:fullerene bulk heterojunction photovoltaic cell is directly measured. The charge‐transfer excitons generated by the sub‐bandgap optical pumping are coupled with the modulating electric field and introduce subtle changes in optical absorption in the sub‐bandgap region. This minimum required energy for sub‐bandgap charge genreation is defined as the effective bandgap.