The structure and optical properties of PVA-BaTiO₃ nanocomposite films

Highlights

• BaTiO₃ nanocrystalline were prepared via tartaric acid precursor method.

• The structure and optical properties of PVA– BaTiO₃ films were investigated.

• Optical dielectric properties and optical conductivity were enhanced with addition of BaTiO₃ nanoparticles in PVA matrix.

Abstract

This paper aims to synthesize barium titanate (BaTiO₃) nanocrystalline particles and to fabricate polyvinyl alcohol (PVA) films hosting BaTiO₃ in order to enhance structural and optical properties. The tartrate precursor process is used to produce BaTiO₃ nanocrystalline. By means of cast solution, the PVA – BaTiO₃ nanocomposite films are prepared. The polymer films are described by X-ray diffractometer (XRD), Fourier-Transform Infrared (FTIR), UV–vis spectroscopy, and photoluminescence spectroscopy (PL). The study of XRD and FTIR indicates that complexity is established between BaTiO₃ nanoparticles and PVA matrix. Furthermore, XRD analyzes emphasize a reduction in the crystallinity of polymer films by increasing of BaTiO₃ nanoparticles within the matrix of PVA. It is noticed that as the BaTiO₃ nanoparticles concentration increases in the PVA matrix, the optical band gap decreases while the Urbach energy increases. The PL spectra for PVA-BT films showed a photoemission peak at about 750 nm. This peak decreases in intensity and broadened with the increase of the BT concentration in the PVA matrix, which is related to the defects produced and causes disordering in the polymer matrix. The extinction coefficient, refractive index, optical conductivity and dielectric constants of the polymer films are also improved.

Introduction

Polymer nanocomposite materials were used in different applications like optoelectronic devices, integrated capacitors, reflective materials, sensors, and photovoltaic cells [1,2]. Their properties such as optical, mechanical, and electrical were amended by using organic and inorganic materials to produce a composite mixture [1]. The benefits of using such polymeric materials in optoelectronic applications stem from the higher stability and the potential to manufacture devices with large areas and improved flexibility substrates. The physical properties of such materials were enhanced by adding fillers or changing their sizes in the polymer matrix [1,3,4].

Improvements of the optical properties of polymer nanocomposites and productions of new nanocomposites have been increasingly a great challenge for materials researchers. Numerous studies to boost the optical characteristics of nanocomposite polymers were conducted [[5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20]]. Numerous nanoparticles, for instance, such as Fe₂O₃ [16], NaI [21,22], graphene oxide [23], NiO [24], Al₂O₃ [25], silica [26], gold [19,27], Al [15,28], Cu [29], Ag [30], Fe [5,31], and metal oxides [20] have been used as a filler material within various polymeric matrices to fine-tune and modify their optical properties to customize the optical parameters for optical industrial applications. Further, new nanocomposites have been produced with properties to meet the demand polymer electronics applications.

Polyvinyl Alcohol (PVA) is considered to be suitable host material for multiple nanoparticles [[32], [33], [34], [35], [36], [37], [38], [39], [40]]. It is motivated by the opportunity to obtain extremely transparent films with righteous optical advantages, highly good flexibility, and enhanced quite dielectric strength.

Barium titanate (BaTiO₃) is ferroelectric ceramic powder with low dielectric loss and high dielectric constant, which enables it to be used in various applications like manufacture of capacitors and piezoelectric transducers. Polymer nanocomposite films containing ceramic fillers have attracted much attention owing to their high dielectric properties, good flexibility, and thermal stability. For instance, Morsi et al. [41] improved the thermal, optical, electrical and dielectrical properties of the polyethylene oxide (PEO)/carboxymethyl cellulose blend by incorporation of different concentration of BaTiO₃. Bhide and Hariharan [42] investigated the effect of BaTiO₃ on the structure and electrical properties of the (PEO)6:NaPO₃ matrix and found that the properties have been enhanced with the increase of the filler concentration. Jun Su and Jun Zhang [43] found that the incorporation of 50 vol fraction of BaTiO₃ into polyethylene composites increase the dielectric constant, dielectric loss, and the mechanical properties improved as well. Recently, Noormohammad Shareef and Chidambaram [44] have been studied the structural and dielectric properties of PVA matrix filled with BaTiO₃ and Boron Nitride and found that the obtained nanocomposite films can be used in organic electronic applications.

Most works in the literature are concerning with the dielectric properties. However, the structure and optical characterizations of PVA-nanocomposite films stuffed by BaTiO₃ nanoparticles have not been investigated previously. Therefore, the main objective in the current work is to investigate the structure and optical characterization of PVA filled with different concentrations of BaTiO₃ nanoparticles, and to enhance their performance in various applications.