Erbium-Doped Nanoparticle-Polymer Composite Thin Films for Photonic Applications: Structural and Optical Properties

Eric Kumi Barimah; Sri Rahayu; Marcin W Ziarko; Nikolaos Bamiedakis; Ian H White; Richard V Penty; Girish M Kale; Gin Jose

doi:10.1021/acsomega.0c00040

Erbium-Doped Nanoparticle-Polymer Composite Thin Films for Photonic Applications: Structural and Optical Properties

ACS Omega. 2020 Apr 14;5(16):9224-9232. doi: 10.1021/acsomega.0c00040. eCollection 2020 Apr 28.

Authors

Eric Kumi Barimah¹, Sri Rahayu¹, Marcin W Ziarko², Nikolaos Bamiedakis², Ian H White^{2

3}, Richard V Penty², Girish M Kale¹, Gin Jose¹

Affiliations

¹ School of Chemical and Process Engineering, University of Leeds, Clarendon Road, Leeds LS2 9JT, U.K.
² Centre for Photonic Systems, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, U.K.
³ University of Bath, Claverton Down, Bath BA2 7AY, U.K.

Abstract

Erbium-doped nanocrystal (NC)-dispersed polymer thin films are attractive core materials for use in optical waveguides as they can provide high optical gain and enable the formation of compact waveguide amplifiers. Nonetheless, there are significant challenges associated with obtaining good dispersibility of NCs into a polymer matrix and favorable optical properties. Therefore, in this paper, we report the fabrication of Er³⁺-doped ceria (EGC) NCs employing the Leeds alginate process (LAP) and their incorporation into a siloxane polymer matrix. The surface morphology and compositional, structural, and optical properties of the fabricated films are evaluated to assess the NC dispersion and their suitability for the waveguide amplifier. The photoluminescence (PL) and lifetime measurements of the NCs-polymer nanocomposite thin film samples show intense, broadband PL emission of the Er³⁺ ions at 1534 nm (⁴I_13/2 → ⁴I_15/3 transition) with a full width at half-maximum (fwhm) of ∼64 nm and lifetime in the range of 2.6-3.0 ms. The inhomogeneously broadened PL spectra and improvement in lifetime of NCs in the polymer are important results that we report. The EGC NCs-polymer nanocomposite thin films also exhibit excellent transparency in the NIR wavelength range and a refractive index in the range of 1.53-1.58 in the visible wavelength. The work presented here clearly demonstrates the potential of using high-quality Er-doped nanocomposite polymer thin films for interesting applications such as compact low-cost waveguide amplifiers and lasers.