FTO optical thin film system as a novel nonlinear media for infrared blocking windows

Accepted Manuscript Design of Rose Bengal/FTO Optical Thin Film System as a Novel Nonlinear Media for Infrared Blocking Windows S.M. El-Bashir, I.S. Yahia, M.A. Binhussain, M.S. AlSalhi PII: DOI: Reference:

S2211-3797(17)30564-8 http://dx.doi.org/10.1016/j.rinp.2017.05.027 RINP 712

To appear in:

Results in Physics

Received Date: Revised Date: Accepted Date:

2 April 2017 27 May 2017 27 May 2017

Please cite this article as: El-Bashir, S.M., Yahia, I.S., Binhussain, M.A., AlSalhi, M.S., Design of Rose Bengal/ FTO Optical Thin Film System as a Novel Nonlinear Media for Infrared Blocking Windows, Results in Physics (2017), doi: http://dx.doi.org/10.1016/j.rinp.2017.05.027

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Design of Rose Bengal/FTO Optical Thin Film System as a Novel Nonlinear Media for Infrared Blocking Windows S.M. El-Bashir 1,2 *, I.S. Yahia3,4, M.A. Binhussain5, M.S. AlSalhi 1 1

Department of Physics & Astronomy, Science College, King Saud University, Riyadh, Saudi Arabia.

2

3

Department of Physics, Faculty of Science, Benha University, Benha, Egypt. Advanced Functional Materials & Optoelectronic Laboratory (AFMOL), Department of Physics,

Faculty of Science, King Khalid University, P.O. Box 9004, Abha, Saudi Arabia. 4

Nanoscience Laboratory for Environmental and Bio-medical Applications (NLEBA),

Semiconductor Lab., Department of Physics, Faculty of Education, Ain Shams University, Roxy, 11757 Cairo, Egypt 5

Department of advanced materials and building, KACST, Riyadh, KSA.

Abstract Rose Bengal (RB) is a new organic semiconductor with the highly stable layer, was deposited on highly cleaned conductive glass substrate known as (FTO glass) with different thickness in the range from 80 – 292 nm. XRD showed an entirely amorphous structure of the studied film thicknesses. The observed peaks are the indexed peaks for FTO layer. Spectrophotometric data as transmittance, reflectance, and absorbance were used for the analysis the optical constant of RB/FTO optical thin film system. Refractive index was calculated using Fresnel's equation with the aid of reflectance and absorption index. The Dielectric constant, dielectric loss and dissipation factor were discussed and analyzed according to the applied optical theories. Nonlinear parameters such as third order nonlinear optical susceptibility and the nonlinear refractive index were calculated based on the linear refractive index of the applications of this material in nonlinear media. The results showed that Rose Bengal is a proving material for wide scale optoelectronic applications such as infrared blocking windows.

Keywords: Rose Bengal, dielectric parameters, Linear/nonlinear optics, Dye/FTO, IR blocking windows. ----------------------------------------------------------------------------*

Corresponding author: S.M. El-Bashir, Associate Prof. at Department of Physics & Astronomy, Science College, King Saud University, Riyadh, Saudi Arabia. Tel.: 966 565850487; fax: 96614673656. E-mail addresses: [email protected]. 1

1- Introduction Optical filters are classified into two categories, dichroic and absorptive Filters [1-3]. A dichroic filter blocks the unwanted light and transmits only the desired spectrum using the principle of optical interference[1-3]. Whereas, in Absorptive filters light, can be incident on the filter from a wide range of angles to modify the light passing through them by absorbing particular wavelength regions[1-3]. Thus, the light can be blocked according to the absorption properties of the substrate used. This idea is ideal for some applications where the damage in a system from unwanted light is a major problem. Such filters are usually including Longpass (LP) which transmit long wavelengths and Short-pass (SP) that transmit short wavelengths[4-7]. In the present work, new short pass (SP) optical window systems

were designed based Rose Bengal (RB) dye thin films coated on fluorine doped tin oxide (FTO) glass substrates with different thicknesses. These colored windows

represent optical infrared (IR) blockers which are special filters that effectively remove damaging thermal radiation while ensuring maximum visible light transmission. Such filters are necessary to be used in conjunction with high power broadband light sources for different applications museum lighting [8]. Additionally, these filters can be applied in smart window glazing since FTO is considered as important optoelectronic material, due to its unique combined electrical and optical properties [9].

Also, these windows can have different

architecture designs to reflect infrared light in summer and transmit it in winter in order to reduce the energy consumption in buildings [10-12]. This way, the costs of air conditioning for cooling and heating and can considerably be reduced [13, 14].

2

2- Experimental Techniques 2.1. Deposition of RB/FTO optical thin film system. Rose Bengal was purchased from Sigma-Aldrich Company without any further purification. The molecular structure of Rose Bengal is shown in Scheme.1 [15] 10-2 M of RB in ethanol was solved to produce a highly soluble solution. RB stock solution was filtered to remove any residuals and kept in the dark for 24 hours. Different thicknesses of RB/conductive glass named fluorine doped tin oxide (RB/FTO) were deposited by using homemade spin coating system with various rotations speeds. The as-deposited films were dried during the rotation process without any annealing process. The home spin coating was calibrated by using AlphaStep IQ surface profile system [16]. 2.2. Devices and measurements X-ray diffraction patterns were obtained by using Shimadzu LabXRD–6000 with CuKα (=1.5406 Å) radiation and a secondary monochromator. The operating voltage of XRD Tube was 30 kV, and the current was 30 mA in the 2θo range (5°- 80°). The spectral distribution of transmittance T (λ ) , reflectance R(λ ) , and

absorbance of the investigated RB/FTO optical thin film system were carried at the normal incidence by using a double beam spectrophotometer (Type JASCO, model V–570, UV-VIS-NIR) in the wavelength range (300–2500 nm).

3

3. Results and discussions 3.1. Theoretical background of linear and nonlinear optical properties.

In an optical media, the relation between the input/output light through the media can be expressed by the following relation [16-23],

I = I oe−αd ,

(1)

where d is the RB film thickness and α are the absorption coefficient and give by

αd = 2.303log( I / Io) ,

(2)

and

α=

2.303x( Abs) , d

where

Abs = ( I / Io)

(3)

is

the

measured

absorbance

automatically

by

the

spectrophotometer. The refraction index can be determined directly from both the reflectance and absorption index if the film thickness is well known. Fresnel's equation was used to determine the refractive index (n) as follows [16-23],

R=

(n − 1) 2 + k 2 , (n + 1) 2 + k 2

(4)

where k is the absorption index and given by k = αλ / 4π . The algebraic solution of Eq.(4) is given by the following [16-23],

 (1 + R)  4R n =   + − k2 , 2 ( 1 − R ) ( R − 1 )  

(5)

4

The complex refractive index for optical media can be expressed by the following [16-23]: n~ = n − ik ,

(6)

Where n is the real art of the refractive index and k is imaginary part of the refractive index. Also, we can able to calculate both the dielectric constant ( ε 1 ) and dielectric loss ( ε 2 ) and the dissipation factor ( tan δ ) on the above basis as follows [16-23]:

ε1 = n 2 − k 2 ,

(7)

ε 2 = 2nk ,

(8)

tan δ = ε 2 / ε1 , (9)

The linear optical susceptibility ( χ (1) ) was calculated according to the following equation [16-27]

χ (1) = (n 2 − 1) / 4π ,

(10)

Also, the third order nonlinear optical susceptibility ( χ (3) ) and nonlinear refractive index ( n ( 2) ) are given by [16-27]:

χ (3 ) =

n

( 2)

A 4

(4π )

(n

2

)

4

−1 ,

(11)

12πχ(3) = , n

(12)

5

3. Results and discussions 3.1. Analysis of XRD patterns of RB/FTO optical thin films system.

X-ray diffraction patterns of RB/FTO optical thin film system of different thicknesses the range from 80 nm to 292 nm is shown in Fig.1. It is clear that the RB film showed an amorphous structure as confirmed by the absence of the diffraction peaks of Rose Bengal. The observed peaks in the XRD pattern are for the FTO layer which is the dominant peaks of such conductive substrate. The FTO layer peaks were indexed according to JCDPS card No.(41-1445). From our previous reported data of organic dyes on conductive FTO substrate, organic dyes showed an amorphous structure with a broad amorphous hump [21-23]. 3.2. Transmittance, reflectance, and the absorbance of RB/FTO optical thin films system.

The transmittance of the studied RB/FTO of different thicknesses was measured in the wavelength from 300 – 2500 nm in compared with the transmittance of transparent FTO layer on glass, as shown in Fig.2. It is clear that the RB/FTO reached 78.5 % for the transparent FTO layer at the visible region. RB/FTO of different thickness showed a clear edge at the UV corresponding to the FTO band gap. While at the visible region, the Rose Bengal showed an absorption valley in the wavelength region from 467-594 nm. Also, at the near infrared region, RB/FTO illustrated a sharp decreased in its values until reached approximately zero. The RB/FTO showed a small variation of thickness dependence in which the width of the absorption valley increased with decreasing the film thickness. The as-deposited RB/FTO can be used in different applications according to the values of the transmittance. The most important features of FTO film is the highly thermal stability 6

on glass, light absorption in the visible region, blocking of near infrared (NIR) region, avoid the heating of the sample under different near-infrared (NIR) light and stable under different environmental conditions [21-23]. At the NIR region, the studied films showed highly reflectance spectrum, in which T=0. Moreover, the transmittance of RB/FTO optical system showed a merged of all curves at NIR region. Fig.3. shows the absorbance (Abs) of the studied RB/FTO films showed a sharp decrease in its values forming the band gap of the FTO layer at the deep UV region. After that, absorbance forming a new absorption valley corresponding to the Rose Bengal itself and a new band gap for RB/FTO is observed for the studied film thicknesses. Such absorption region is described the color centers in Rose Bengal structure [28-31]. It is evident from the Scheme.1; Rose Bengal has the complex aromatic molecular structure gets a firm and bright color to other substances. Dyes can be absorbed the light due to the existence of C ‒ C = C ‒ C = C ‒ described as double bond and then single bond and followed by a double bond between carbon atoms. There is a group of atoms in every colored compound called chromophore which it is responsible for producing the color of the dye [28-31]. Chromophores often are -C=C-, -C=O, -C=N-, -NO2, -N=N- and quinoid rings. Hence, dyes include the delocalized electrons from the double bonds, chromophores, and auxochromes, which usually are -COOH,-NH3,–OH and -SO3H [28-31] . It is important to mention that the absorption valley of RB can be described as Q-band in the wavelength region from 467 to 594 nm in the visible region, While, Soret band cannot observe in the deep UV region [32-34] . This absorption peak can be ascribed as transitions between π-π* between bonding and anti-bonding orbitals [32-34].

At the higher wavelengths, the abs are increased in the NIR region. The reflectance of RB/FTO optical thin film system was measured and plotted in Fig.4. It 7

is clear that the reflectance showed multi-position peaks with the valley at the lower wavelength regions. While at the higher wavelengths especially at NIR regions, the reflectance increases rapidly with increasing the incident light. Such behavior was expected for RB/FTO of different thickness due to the transmittance is very low and equals to zero. The same trend was observed and reported before by I.S. Yahia et.al [21, 22, 31]. 3.2. Refractive/absorption indices, dielectric properties of RB/FTO optical thin films system.

Absorption index (k) and refractive index (n) for different thickness of RB/FTO optical system are shown in Figs. (5&6), respectively. The absorption index was calculated on the basis of Eq.(2b) and k = αλ / 4π . The absorption index showed three distinct regions, the first region corresponding to the FTO layer at deep UV region in which the absorption index decreased with wavelengths. While for the second region, the absorption index showed a peak/valley correspond to the absorption region of Rose Bengal. Finally, at the NIR regions, the absorption index decreased with increasing the film thickness but increased with increasing the wavelengths in that region. Such decreasing of the (k) with wavelengths can be attributed to higher thickness induced some deformation of crystalline state and so, a new change in the electronic structure [35]. The refractive index (n) is a key for optoelectronic, optical communications, telecommunications, filters, optical switches, photonic applications, waveguides and cables [36]. The refractive index was calculated by using Eqs. (4&5). The refractive index is showed multi-oscillating peaks and valley at the lower wavelengths for the studied thicknesses of RB/FTO optical system. Approximately, the mean values of the

8

refractive index in this region equals to 2 (See Fig.6). While, in the NIR region, the refractive index showed an anomalous trend in which it is increased with increasing the incident wavelengths. The RB/FTO optical system showed a small variation on the film thicknesses. The refractive index possesses the same trend as the measured reflectance for the studied RB/FTO optical system. Also, it is observed that at the higher wavelength, the values of refractive index is very high and ranged from 2-9 in its values due to the values of reflectance in this region. The anomalous behavior of (n) can be attributed to multi-oscillator model [36-38]. For optical media/materials, multi-resonated frequencies can occur as ascribed as a multi-oscillator. Such resonance can be discussed on the basis on lattice vibrations in the near infrared regions and to the oscillations of the bound electrons of the atoms in UV-regions. For such media of multi-oscillator under different frequencies, the polarization proportional to the dielectric and so, an anomalous behavior of refractive index can be happened [36-38]. Dielectric constant, dielectric loss and dissipation factor are very important to design the optoelectronic devices [39-41]. The above constants were calculated according to Eqs.(7-9), respectively. The dielectric constant is related to the steep down of light speed inside the materials while the dielectric loss is responsible for the energy absorption from the electric field due to dipole motion and interaction [39-41]. The dielectric parameters of RB/FTO optical thin film systems having different thickness are shown in Figs. (7-9), respectively. The dielectric constant decreases at the lower photon energy. After that, with increasing the photon energy, the dielectric constant approximately constant. The dielectric constant showed a thickness dependence in which its values increased with increasing the film thickness. Such growing in the dielectric constant with film thickness can be attributed to the highly 9

optical response of these films (i.e. the dissipation energy under the electric field is decreased) [39-41]. The dielectric loss is decreased at the lower photon energy. With increasing the photon energy, the dielectric loss remains constant, and at the higher photon energy, its values increased again. The illustrated peaks and valley in the plotted of dielectric constant and loss is due to the interaction between materials electrons and the incident photons [42]. It is also evident that the dielectric constant decrease with increasing the film thickness. The dissipation factor is a key for the absorption and dissipation of field energy inside the studied samples. It is clear that the dissipation factor is decreased with increasing the photon energy followed by constant values through a wide range of photon energy. The appeared of peaks and valley in the medium range of photon energy is described by the interaction of light photon energy with the electrons. At the higher photon energy, the dissipation factor is increased again [43-47]. The dissipation factor was increased with increasing the film thickness. 3.3. Nonlinear optics of RB/FTO optical thin films system.

The optical nonlinearity in organic materials is very high in comparison to the organic materials due to the delocalized π-electrons [16]. Organic material possesses high values of nonlinear parameters especially when it is deposited on conductive glass substrates such fluorine-doped tin oxide (FTO) [3-5] and indium tin oxide (ITO) [48]. Third order nonlinear optical susceptibility is the key parameters in the high capacity network communications [49]. The nonlinear material can be used in many applications such as optical circuits, ultra-fast optical switching, and electro-optical modulators [25, 50].

10

The linear optical susceptibility ( χ (1) ) is calculated from Eq.10. The plotting of ( χ (1) ) is shown in Fig.10. it is clear that the ( χ (1) ) is almost constant up to 1500 nm followed by high values at the NIR region. Such behavior is expected for organic dye deposited on FTO glass. Also, the values of ( χ (1) ) is a thickness dependent. I.S. Yahia et all studied the Rhodamine B/FTO glass, and they found that the values of ( χ (1) ) increased with increasing the photon energy with maximum values reached to 4[31]. H.Y. Zahran et al. studied Fluorescein dye/FTO glass, and they found that the maximum values of ( χ (1) ) reached 2.456 [23]. It is clear that Rose Bengal possess high linear optical susceptibility, such high values can be attributed to the different molecular structure of Rose Bengal and may be the four iodine atoms incorporated in this structure can affect such new behavior. The third order nonlinear optical susceptibility ( χ (3) ) was calculated on the basis of Eq.11. The ( χ (3) ) was plotted in Fig.11 for Roe Bengal of different thickness on FTO glass. It is clear that the ( χ (3) ) is increased with increasing the incident light and thickness. The values of ( χ (3) ) reached 4 x10 -7 esu as maximum values for this optical system. The nonlinear refractive index ( n ( 2) ) was calculated on the basis of Eq.12. The ( n ( 2) ) was plotted in Fig.12 for Roe Bengal of different thickness on FTO glass. It is clear that the ( n ( 2) ) is also increased with increasing the incident light and thickness. The values of ( n ( 2) ) reached 1.6 x10 -6 esu. It is clear that the values of ( χ (3) ) the ( n ( 2) ) for RB/FTO is higher than Fluorescein /FTO [23] and RhB/FTO[31] organic thin film materials. The maximum values of ( χ (3) ) the ( n ( 2) ) for RB/FTO can be attributed to the molecular structure of RB.

11

4. Conclusion

It is concluded that FTO layer supports the enhancement the optical nonlinearity of Rose Bengal organic dye for short pass (SP) optical windows. This can be ascribed to to the fact that the incident light can change intramolecular motion and orientation of the studied media. Such interaction leads to the increasing of the nonlinear optical parameters.

It is important to notice that such high values of

nonlinear parameters can open new applications of RB dye such as high speed optical switching [51, 52]. This work represents a promising extension to our previous work in long-pass (LP) optical windows which can effectively block harmful UV radiation [53]. Thus, our UV/IR-Blocking windows can effectively remove damaging ultraviolet and unwanted IR thermal that can negatively impact the energy saving in the building environments specially in hot countries like KSA. Finally, our studies showed that these windows are transparent over the visible region promoting high illumination levels inside buildings so, that much energy spent in lighting can be saved.

Acknowledgement

This research was supported by King Abdul-Aziz City for Science and Technology (KACST- Saudi Arabia) grant no. AT-35-18. References [1]H.A. Macleod, Thin-film optical filters, CRC press2001. [2]R.D. Hudson Jr, Infrared system engineering, DOI.(1969) [3]L.I. Epstein, The design of optical filters, JOSA, 42 (1952) 806-810. [4]J.-I. Park, C.-S. Kim, J. Kim, J.-S. Park, Y. Qian, D. Ahn, T. Itoh, Modeling of a photonic bandgap and its application for the low-pass filter design, Microwave Conference, 1999 Asia Pacific, IEEE, 1999, pp. 331-334. 12

[5]C. Madsen, G. Lenz, A. Bruce, M. Cappuzzo, L. Gomez, R. Scotti, Integrated all-pass filters for tunable dispersion and dispersion slope compensation, IEEE photonics technology letters, 11 (1999) 1623-1625. [6]O. Hofmann, X. Wang, A. Cornwell, S. Beecher, A. Raja, D.D. Bradley, Monolithically integrated dye-doped PDMS long-pass filters for disposable on-chip fluorescence detection, Lab on a Chip, 6 (2006) 981-987. [7]V. Lehmann, R. Stengl, H. Reisinger, R. Detemple, W. Theiss, Optical shortpass filters based on macroporous silicon, Applied Physics Letters, 78 (2001) 589-591. [8]M. Scuello ,I. Abramov, J. Gordon, S. Weintraub, Museum lighting: Why are some illuminants preferred?, JOSA A, 21 (2004) 306-311. [9]P. Gerhardinger, D. Strickler, Fluorine doped tin oxide coatings-over 50 years and going strong, Key Engineering Materials, Trans Tech Publ, 2008, pp. 169-178. [10]M.-C. Dubois, Å. Blomsterberg, Energy saving potential, and strategies for electric lighting in future North European, low energy office buildings: A literature review, Energy, and Buildings, 43 (2011) 2572-2582. [11]A.R .Webb, Considerations for lighting in the built environment: Non-visual effects of light, Energy, and Buildings, 38 (2006) 721-727. [12]L. Edwards, P.A. Torcellini, A literature review of the effects of natural light on building occupants, National Renewable Energy Laboratory Golden, CO2002. [13]R. Baetens, B.P. Jelle, A. Gustavsen, Properties, requirements, and possibilities of smart windows for dynamic daylight and solar energy control in buildings: A state-of-the-art review, Solar Energy Materials and Solar Cells, 94 (2010) 87-105. [14]P.H. Shaikh, N.B.M. Nor, P. Nallagownden, I. Elamvazuthi, T. Ibrahim, A review on optimized control systems for building energy and comfort management of smart, sustainable buildings, Renewable and Sustainable Energy Reviews, 34 (2014) 409-429. [15]H. Zeyada, M. Youssif, N. El-Ghamaz, M. Aboderbala, Spectral, structural, optical and dielectrical studies of UV irradiated Rose Bengal thin films prepared by spin coating technique, Physica B: Condensed Matter, 506 (2017) 75. 82[16]J.-M. Choi, S. Im, Ultraviolet enhanced Si-photodetector using p-NiO films, Applied Surface Science, 244 (2005) 435-438. [17]M. Abutalib, M. Shkir, I. Yahia, S. AlFaify, A. El-Naggar, V. Ganesh, Thickness dependent optical dispersion and nonlinear optical properties of nanocrystalline fluorescein dye thin films for optoelectronic applications, Optik-International Journal for Light and Electron Optics, 127 (2016) 6601-6609. [18]V. Ganesh, H. Zahran, I. Yahia, M. Shkir, S. AlFaify, Enhancement of nonlinear optical susceptibility of CuPc films by ITO layer, Optical Materials, 62 (2016) 184-191. [19]J. Iqbal, I. Yahia, H. Zahran, S. AlFaify, A. AlBassam, A. El-Naggar, Linear and non-linear optics of nano-scale 2′, 7′ dichloro-fluorescein/FTO optical system: Bandgap and dielectric analysis, Optical Materials, 62 (2016) 527-533. [20]J.I. Pankove, Optical processes in semiconductors, Courier Corporation2012. [21]I. Yahia, V. Ganesh, M. Shkir, S. AlFaify, H. Zahran, H. Algarni, M. Abutalib, A.A. AlGhamdi, A. El-Naggar, A. AlBassam, An investigation on linear and non-linear optical constants of nano-spherical CuPc thin films for optoelectronic applications, Physica B: Condensed Matter, 496 (2016) 9-14. [22]I. Yahia, H. Zahran, F. Alamri, Spectrophotometric calculations of optical linearity and nonlinearity of nanostructured Pyronin Y/FTO optical system for optoelectronic applications, Synthetic Metals, 222 (2016) 186-191. [23]H. Zahran, J. Iqbal, I. Yahia, Optical constants and nonlinear calculations of fluorescein/FTO thin film optical system, Physica B: Condensed Matter, 500 (2016) 98-105. [24]R. Adair, L. Chase, S.A. Payne, Nonlinear refractive index of optical crystals, Physical Review B, 39 (1989) 3337. 13

[25]H. Ticha, L. Tichy, Semiempirical relation between non-linear susceptibility (refractive index), linear refractive index and optical gap and its application to amorphous chalcogenides, J. Optoelectron. Adv. Mater, 4 (2002) 381-386. [26]C.C. Wang, Empirical relation between the linear and the third-order nonlinear optical susceptibilities, Physical Review B, 2 (1970) 2045. [27]J. Wynne, N. Bloembergen, Measurement of the Lowest-Order Nonlinear Susceptibility in III—V Semiconductors by Second-Harmonic Generation with a C O 2 Laser, Physical Review, 188 (1969) 1211. [28]E. Donath, Molecular design. Chemical structure generation from the properties of pure organic compounds, Zeitschrift für Physikalische Chemie, 186 (1994) 123-124. [29]T. Ryerson, A. Andrews, W. Angevine, T. Bates, C. Brock, B. Cairns, R. Cohen, O. Cooper, J. Gouw, F. Fehsenfeld, The 2010 California research at the Nexus of air quality and climate change (CalNex) field study, Journal of Geophysical Research: Atmospheres, 118 (2013) 5830-5866. [30]J. Sivathasan, Preparation of Clay-dye pigment and its dispersion in polymers, DOI .(2007) [31]I. Yahia, A. Jilani, M. Abutalib, S. AlFaify, M. Shkir, M.S. Abdel-wahab, A.A. Al-Ghamdi, A. El-Naggar, A study on linear and non-linear optical constants of Rhodamine B thin film deposited on FTO glass, Physica B: Condensed Matter, 490 (2016) 25-30. [32]M. El-Nahass, F. Abu-Samaha, S. Menshawy, E. Elesh, Effect of annealing on structural and optical properties of copper tetraphenylporphyrin (CuTPP) thin films, Optics & Laser Technology, 64 (2014) 28-33. [33]M. Gouterman, D. Holten, E. Lieberman, Porphyrins XXXV. Exciton coupling in μ-oxo Scandum dimers, Chemical Physics, 25 (1977) 139-153. [34]J.B. Kim, J.J. Leonard, F.R. Longo, Mechanistic study of the synthesis and spectral properties of meso-tetraarylporphyrins, Journal of the American Chemical Society, 94 (1972) 3986-3992. [35]S. El-Bashir, Photophysical properties of PMMA nanohybrids and their applications: luminescent solar concentrators & smart greenhouses, LAP LAMBERT Academic Publishing2012. [36]M.I. Tribelsky, J.-M. Geffrin, A. Litman, C. Eyraud, F. Moreno, Small dielectric spheres with high refractive index as new multifunctional elements for optical devices, Scientific reports, 5 (2015) 12288. [37]M. Fox, Optical properties of solids, AAPT, 2002. [38]H. Zeyada, M. El-Nahass, I. El-Zawawi, E. El-Menyawy, Structural and optical properties of thermally evaporated 2-(2, 3-dihydro-1, 5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-ylimino)2-(4-nitrophenyl) acetonitrile thin films, Journal of Physics and Chemistry of Solids, 71 (2010) 867-873. [39]F. Abelès, Optical properties of solids, DOI.(1972) [40]M. El-Nahass, H.A. El-Khalek, A. Nawar, Structural and optical characterizations of Ni (II) tetraphenyl porphyrin thin films ,The European Physical Journal Applied Physics, 57 (2012) 30201. [41]P. Sharma, V. Sharma, S. Katyal, variation of optical constants in Ge10Se60Te30 thin film, Chalcogenide letters, 3 (2006) 73-79. [42]D.L. Wise, Electrical and Optical Polymer Systems :Fundamentals: Methods, and Applications, CRC Press1998. [43]M. Abdel-Aziz, E. El-Metwally, M. Fadel, H. Labib, M. Afifi, Optical properties of amorphous Ge Se Tl system films, Thin solid films, 386 (2001) 99-104. [44]M. Abdel-Aziz, I. Yahia, L. Wahab ,M. Fadel, M. Afifi, Determination and analysis of dispersive optical constant of TiO 2 and Ti 2 O 3 thin films, Applied surface science, 252 (2006) 8163-8170. 14

[45]A. El-Korashy, H. El-Zahed, M. Radwan, Optical studies of [N (CH 3) 4] 2 CoCl 4,[N (CH 3 ( 2 [4MnCl 4 single crystals in the normal paraelectric phase, Physica B: Condensed Matter, 334 (2003) 75-81. [46]M. Fadel, S. Fayek, M. Abou-Helal, M. Ibrahim, A. Shakra, Structural and optical properties of SeGe and SeGeX (X= In, Sb and Bi) amorphous films, Journal of Alloys and Compounds, 485 (2009) 604-609. [47]S.A. Khan, F. Al-Hazmi, S. Al-Heniti, A. Faidah, A. Al-Ghamdi, Effect of cadmium addition on the optical constants of thermally evaporated amorphous Se–S–Cd thin films, Current Applied Physics, 10 (2010) 145-152. [48]H. Kim, J. Horwitz, W. Kim, A. Mäkinen, Z. Kafafi, D. Chrisey, Doped ZnO thin films as anode materials for organic light-emitting diodes, Thin solid films, 420 (2002) 539-543. [49]D. Cotter, R. Manning, K. Blow, A. Ellis, A. Kelly, D. Nesset, I. Phillips, A. Poustie, D. Rogers, Nonlinear optics for high-speed digital information processing, Science, 286 (1999) 1523-1528. [50]M. Frumar, J. Jedelský, B. Frumarova, T. Wagner, M. Hrdlička, Optically and thermally induced changes of structure, linear and non-linear optical properties of chalcogenides thin films, Journal of non-crystalline solids, 326 (2003) 399-404. [51]G. Jiang, S. Wang, W. Yuan, L. Jiang, Y. Song, H. Tian, D. Zhu, Highly fluorescent contrast for rewritable optical storage based on photochromic bisthienylethene-bridged naphthalimide dimer, Chemistry of materials, 18 (2006) 235-237. [52]T. Kaino, Y. Katayama, Polymers for optoelectronics, Polymer Engineering & Science, 29 (1989) 1209-1214. [53] S.M. El-Bashir, I.S.Yahia, M.A.Binhussain, M.S. AlSalhi, Designing of PVA/Rose Bengal Long-Pass Optical Window Applications, Results in Physics, (2017) accepted.

15

List of Figures

Scheme.1. Molecular structure of Rose Bingal [15].

16

10

20

30

40

50

60

[311]

[301]

[310]

[211] [220]

[200]

[110]

[101]

Intensity, (a.u.)

80 nm 118 nm 183 nm 240 nm 292 nm

70

80

2θ θo

Fig.1. XRD patterns of RB/FTO optical thin film system of different thicknesses.

17

100 Max. Transmitance of FTO/glass

T%

80

292 nm 240 nm 183 nm 118 nm 80 nm T pure FTO

60

40

20

0 300

600

900

1200

1500

1800

2100

2400

λ, (nm)

Fig.2. Transmittance of RB/FTO optical thin film system of different thicknesses.

18

3

292 nm 240 nm 183 nm 118 nm 80 nm

Abs.

2

1

0 300

600

900

1200

1500

1800

2100

2400

λ, (nm)

Fig.3. Absorbance of RB/FTO optical thin film system of different thicknesses.

19

70 292 nm 240 nm 183 nm 118 nm 80 nm

60

R, (%)

50 40 30 20 10 0 300

600

900

1200

1500

1800

2100

2400

λ, (nm)

Fig.4. Reflectance of RB/FTO optical thin film system of different thicknesses.

20

0.12 292 nm 240 nm 183 nm 118 nm 80 nm

Absorption index, (k)

0.10 0.08 0.06 0.04 0.02 0.00 300

600

900

1200

1500

1800

2100

2400

λ, (nm) Fig.5. Absorption index of RB/FTO optical thin film system of different thicknesses.

21

292 nm 240 nm 183 nm 118 nm 80 nm

Refractive index, (n)

10

8

6

4

2 Approx. constant around 2 0 300

600

900

1200

1500

1800

2100

2400

λ, (nm)

Fig.6. Refractive index of RB/FTO optical thin film system of different thicknesses.

22

292 nm 240 nm 183 nm 118 nm 80 nm

Dielectric constant, (εε1)

80

60

40

20

0 0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

hυ υ, (eV)

Fig.7. Dielectric constant of RB/FTO optical thin film system of different thicknesses.

23

Dielectric loss, (εε2)

2.0 292 nm 240 nm 183 nm 118 nm 80 nm

1.5

1.0

0.5

0.0 0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

hυ υ, (eV)

Fig.8. Dielectric loss of RB/FTO optical thin film system of different thicknesses.

24

0.030 292 nm 240 nm 183 nm 118 nm 80 nm

0.025

tanδ δ

0.020 0.015 0.010 0.005 0.000 0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

hυ υ, (eV)

Fig.9. Dissipation factor of RB/FTO optical thin film system of different thicknesses.

25

7 292 nm 240 nm 183 nm 118 nm 80 nm

6 5

χ (1)

4 3 2 1 0 300

600

900

1200

1500

1800

2100

2400

λ, (nm)

Fig.10. Linear optical susceptibility of RB/FTO optical thin film system of different

thicknesses.

26

4x10-7

292 nm 240 nm 183 nm 118 nm 80 nm

χ(3)

3x10-7

2x10-7

1x10-7

0 300

600

900

1200

1500

1800

2100

2400

λ, (nm)

Fig.11. Third order nonlinear optical susceptibility of RB/FTO optical thin film

system of different thicknesses.

27

1.6x10-6

292 nm 240 nm 183 nm 118 nm 80 nm

n (2)

1.2x10-6

8.0x10-7

4.0x10-7

0.0 300

600

900

1200

1500

1800

2100

2400

λ, (nm)

Fig.12. Nonlinear refractive index of RB/FTO optical thin film system of different

thicknesses.

28