Two-Photon Fluorescence in Red and Violet Conjugated Polymer Microspheres

Yanyan Zhi; Ziwei Feng; Tanisha Mehreen; Xiaoyuan Liu; Kirsty Gardner; Xiangping Li; Bai-Ou Guan; Lijuan Zhang; Sergey I. Vagin; Bernhard Rieger; Alkiviathes Meldrum

doi:10.3390/inorganics10070101

Inorganics (Jul 2022)

Two-Photon Fluorescence in Red and Violet Conjugated Polymer Microspheres

Yanyan Zhi,
Ziwei Feng,
Tanisha Mehreen,
Xiaoyuan Liu,
Kirsty Gardner,
Xiangping Li,
Bai-Ou Guan,
Lijuan Zhang,
Sergey I. Vagin,
Bernhard Rieger,
Alkiviathes Meldrum

Affiliations

Yanyan Zhi: Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China
Ziwei Feng: Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China
Tanisha Mehreen: Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
Xiaoyuan Liu: Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
Kirsty Gardner: Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
Xiangping Li: Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China
Bai-Ou Guan: Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China
Lijuan Zhang: Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
Sergey I. Vagin: Wacker Chair of Macromolecular Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85747 Garching bei München, Germany
Bernhard Rieger: Wacker Chair of Macromolecular Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85747 Garching bei München, Germany
Alkiviathes Meldrum: Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada

DOI: https://doi.org/10.3390/inorganics10070101
Journal volume & issue: Vol. 10, no. 7
p. 101

Abstract

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We investigate the two-photon fluorescence (TPF) of conjugated polymer (CP) microspheres with diameters up to tens of micrometers. Two polymers, emitting in either the violet or red, were first synthesized and characterized in terms of their one-photon fluorescence and three-dimensional internal microstructure. Under femtosecond infrared excitation, both types of microspheres showed a strong TPF, which was investigated by the excitation intensity dependence, emission spectroscopy, time-resolved luminescence, and photobleaching dynamics. While the violet-fluorescent microspheres performed similarly compared to dye-doped polystyrene counterparts emitting at a similar wavelength, the red-fluorescent microspheres showed a two-orders-of-magnitude stronger TPF. This excellent performance is attributed to enhanced hyperpolarizability associated with intermolecular interactions in the polymer solid, indicating a route toward designed CP microspheres that could outperform currently-available microparticles for sensing or imaging applications involving two-photon fluorescence.

Published in Inorganics

ISSN: 2304-6740 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Chemistry: Inorganic chemistry
Website: http://www.mdpi.com/journal/Inorganics

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