Inverting the Handedness of Circularly Polarized Luminescence from Light-Emitting Polymers Using Film Thickness

Autor: Jessica Wade, Matthew J. Fuchter, Li Wan, Francesco Salerno, Thomas J. Penfold, Xuhua Wang, Alasdair J. Campbell, Oriol Arteaga, Beth Laidlaw
Přispěvatelé: Engineering & Physical Science Research Council (EPSRC)
Rok vydání: 2019
Předmět:
Technology
Circular dichroism
Chemistry
Multidisciplinary
Materials Science
General Physics and Astronomy
Materials Science
Multidisciplinary
CHIRAL SENSOR
02 engineering and technology
Electroluminescence
EXCITON
010402 general chemistry
01 natural sciences
Polyfluorene
chemistry.chemical_compound
ELECTROLUMINESCENCE
General Materials Science
chiroptical
Nanoscience & Nanotechnology
Thin film
Circular polarization
Science & Technology
Chemistry
Physical
business.industry
OLEDs
POLYFLUORENE
General Engineering
021001 nanoscience & nanotechnology
circular dichroism
0104 chemical sciences
chiral
Chemistry
thin films
STATES
chemistry
Physical Sciences
circular polarization
light emission
Science & Technology - Other Topics
Optoelectronics
Light emission
Photonics
0210 nano-technology
business
Luminescence
Zdroj: ACS Nano. 13:8099-8105
ISSN: 1936-086X
1936-0851
DOI: 10.1021/acsnano.9b02940
Popis: The emission of circularly polarized light is central to many applications, including data storage, optical quantum computation, biosensing, environmental monitoring, and display technologies. An emerging method to induce (chiral) circularly polarized (CP) electroluminescence from the active layer of polymer light-emitting diodes (polymer OLEDs; PLEDs) involves blending achiral polymers with chiral small-molecule additives, where the handedness/sign of the CP light is controlled by the absolute stereochemistry of the small molecule. Through the in-depth study of such a system we report an interesting chiroptical property: the ability to tune the sign of CP light as a function of active layer thickness for a fixed enantiomer of the chiral additive. We demonstrate that it is possible to achieve both efficient (4.0 cd/A) and bright (8000 cd/m2) CP-PLEDs, with high dissymmetry of emission of both left-handed (LH) and right-handed (RH) light, depending on thickness (thin films, 110 nm: gEL = 0.51, thick films, 160 nm: gEL = -1.05, with the terms "thick" and "thin" representing the upper and lower limits of the thickness regime studied), for the same additive enantiomer. We propose that this arises due to an interplay between localized CP emission originating from molecular chirality and CP light amplification or inversion through a chiral medium. We link morphological, spectroscopic, and electronic characterization in thin films and devices with theoretical studies in an effort to determine the factors that underpin these observations. Through the control of active layer thickness and device architecture, this study provides insights into the mechanisms that result in CP luminescence and high performance from CP-PLEDs, as well as demonstrating new opportunities in CP photonic device design.
Databáze: OpenAIRE
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