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Elimination of charge carrier trapping in diluted semiconductors
In 1962, Mark and Helfrich demonstrated that the current in a semiconductor containing traps is reduced by N / N t r , with N the amount of transport sites, N t the amount of traps and r a number that depends on the trap energy distribution. For r > 1, the possibility opens that trapping effects...
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Published in: | Nature materials 2016-06, Vol.15 (6), p.628-633 |
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Main Authors: | , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | In 1962, Mark and Helfrich demonstrated that the current in a semiconductor containing traps is reduced by
N
/
N
t
r
, with
N
the amount of transport sites,
N
t
the amount of traps and
r
a number that depends on the trap energy distribution. For
r
> 1, the possibility opens that trapping effects can be nearly eliminated when
N
and
N
t
are simultaneously reduced. Solution-processed conjugated polymers are an excellent model system to test this hypothesis, because they can be easily diluted by blending them with a high-bandgap semiconductor. We demonstrate that in conjugated polymer blends with 10% active semiconductor and 90% high-bandgap host, the typical strong electron trapping can be effectively eliminated. As a result we were able to fabricate polymer light-emitting diodes with balanced electron and hole transport and reduced non-radiative trap-assisted recombination, leading to a doubling of their efficiency at nearly ten times lower material costs.
By diluting conjugated polymers in high-bandgap host matrices it is shown that electron trapping effects can be significantly reduced. This approach is used to fabricate polymer LEDs with enhanced efficiency and reduced fabrication costs. |
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ISSN: | 1476-1122 1476-4660 |
DOI: | 10.1038/nmat4626 |