@article{Hamilton:2018:10.1021/acsami.8b00243,
author = {Hamilton, I and Chander, N and Cheetham, NJ and Suh, M and Dyson, M and Wang, X-H and Stavrinou, PN and Cass, M and Bradley, DDC and Kim, J-S},
doi = {10.1021/acsami.8b00243},
journal = {ACS Applied Materials and Interfaces},
pages = {11070--11082},
title = {Controlling molecular conformation for highly efficient and stable deep-blue copolymer light-emitting diodes},
url = {http://dx.doi.org/10.1021/acsami.8b00243},
volume = {10},
year = {2018}
}

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TY  - JOUR
AB  - We report a novel approach to the achievement of deep-blue, high-efficiency, and long-lived solution processed polymer light-emitting diodes (PLEDs) via a simple molecular-level conformation change whereby we introduce rigid β-phase segments into a 95% fluorene - 5% arylamine copolymer emission layer (EML). The arylamine moieties at low density act as efficient exciton formation sites in PLEDs whilst the conformational change alters the nature of the dominant luminescence from a broad, charge-transfer like emission to a significantly blue-shifted and highly vibronically structured, excitonic emission. As a consequence, we observe a significant improvement in Commission International de L'Eclairage (CIE) (x, y) co-ordinates from (0.149, 0.175) to (0.145, 0.123) whilst maintaining high efficiency and improving stability. We achieve peak luminous efficiency, η = 3.60 cd/A and luminous power efficiency, ηw = 2.44 lm/W; values that represent state of the art performance for single copolymer deep-blue PLEDs. These values are five-fold better than for otherwise-equivalent, β-phase poly(9,9-dioctylfluorene) (PFO) EML PLEDs (0.70 cd/A and 0.38 lm/W). This report represents the first demonstration of the use of molecular conformation as a vector to control the optoelectronic properties of a fluorene copolymer; previous examples have been confined to homopolymers.
AU  - Hamilton,I
AU  - Chander,N
AU  - Cheetham,NJ
AU  - Suh,M
AU  - Dyson,M
AU  - Wang,X-H
AU  - Stavrinou,PN
AU  - Cass,M
AU  - Bradley,DDC
AU  - Kim,J-S
DO  - 10.1021/acsami.8b00243
EP  - 11082
PY  - 2018///
SN  - 1944-8244
SP  - 11070
TI  - Controlling molecular conformation for highly efficient and stable deep-blue copolymer light-emitting diodes
T2  - ACS Applied Materials and Interfaces
UR  - http://dx.doi.org/10.1021/acsami.8b00243
UR  - https://www.ncbi.nlm.nih.gov/pubmed/29508604
UR  - http://hdl.handle.net/10044/1/57897
VL  - 10
ER  - 

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