Optical characterization and all-optical switching of benzenesulfonamide azo dye

Accepted Manuscript Title: Optical characterization and all-optical switching of benzenesulfonamide azo dye Author: Mohammed F. Al-Mudhaffer Alaa Y. Al-Ahmad Qusay M. Ali Hassan Chassib A. Emshary PII: DOI: Reference:

S0030-4026(15)00943-2 http://dx.doi.org/doi:10.1016/j.ijleo.2015.08.176 IJLEO 56100

To appear in: Received date: Accepted date:

28-8-2014 25-8-2015

Please cite this article as: M.F. Al-Mudhaffer, A.Y. Al-Ahmad, Q.M.A. Hassan, C.A. Emshary, Optical characterization and all-optical switching of benzenesulfonamide azo dye, Optik - International Journal for Light and Electron Optics (2015), http://dx.doi.org/10.1016/j.ijleo.2015.08.176 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.

Optical characterization and all-optical switching of benzenesulfonamide azo dye Mohammed F. Al-Mudhaffer, Alaa Y. Al-Ahmad, Qusay M. Ali Hassan* and Chassib A. Emshary

Basrah, Iraq

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* Corresponding author

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Department of Physics, College of Education for Pure Sciences, University of Basrah,

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E mail: [email protected] ; Tel: 009647703156943

Abstract

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A film of benzenesulfonamide azo dye have been prepared by spray pyrolysis method onto BK7 glass substrate with average thickness of 2.7 µm. This azo dye was derived from

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sulfamethoxazole and chromotropic acid by the Fox method. The optical constants (refractive index, n, extinction coefficient, k, dielectric constant, ε, optical, σopt, and

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electrical, σe, conductivities) were calculated for azo dye film by using spectrophotometer measurements of the absorption, transmittance and reflectance at normal incidence in the

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spectral range 300–900 nm. Third order nonlinear properties has been characterized by calculating the effective thermal nonlinear refractive index, n2, and thermo-optic coefficient, dn/dT, of the azo dye solution using thermal lens technique. Furthermore the thermal lens effect was utilized to demonstrate all optical switching for the sample solution.

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Keyword: Azo dye; Optical properties; Thermal lens technique; Optical switching. PACS numbers: 42.65.-k; 42.65.Jx; 42.65.An; 78.20.N-

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1. Introduction In recent years, the search for novel optical materials has increased owe to their applications in optical devices such as optical modulation, optical information, optical data storage and imaging [1,2]. Detailed investigations of linear and nonlinear optical coefficients

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enable to fabricate materials, appropriately designed at the molecular level for specific applications such as optoelectronic devices [3,4]. Azo dyes have drawn considerable

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attention due to their optical characteristics such as optical data storage and nonlinear optics [5]. Although the optical parameters of thin films are of crucial importance, few researches

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have so far focused on optical parameters of azo dye films [6]. Optical tests giving

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transmittance and reflectance spectra provide the data to determine optical constants such as refractive index, n, extinction coefficient, k, and dielectric constant, ε [7]. The analysis of

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optical absorption could provide useful information to the elucidation of electronic structure of material [8]. Other analysis showed that optical absorption spectra could provide the

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necessary parameters to determine direct and indirect transitions occurring in the band gaps of the materials [9]. High-speed and high-sensitivity optical devices play important roles in

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optical information processing, optical computation and optical communication. Therefore, the study of all-optical switching characteristics is of importance. The optical switching property is closely concerned with the material of the device. Many materials for optical switching device have been reported, including rodamine-B-doped and Au(111)-doped

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PMMA film [10] ,2-(2'-hydroxy phenyl) benzoxazole [11], hydrogenated amorphons siliconsulfur alloy [12], Pt:ethynyl complex [13], photochromic dithienylethene derivatines [14], ethyl red doped polymer film [15], bromophenol blue solutions [16], antiferroelectric liquid crystals [17], congo red in solution [18], dye doped liquid crystal gel [19], liquid crystal cells [20],ytterbium doped fiber [21-23], etc. The optical switches based on organic materials are superior to traditional ones based on inorganic materials due to their higher sensitivities and 2

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easier fabrication process. Especially, the azo polymer offers great potential applications ranging from optical data storage [24], to optical switching, due to the flexibility [25], the compatibility in fabrication [26] and the reversible trans-cis- trans photoisomerization[27]. Optical switching have been studied extensively in azo materials such as azobenzene

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containing polymer films [28],in azo-dye doped polymer waveguide [29], azo polymer material [24,27] and azo polymer waveguide[18]. In these studies the switching process is

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attributed to trans-cis photo isomerzation of azo dyes followed by cis-trans thermal or optical

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relaxation [29].

This work reports the optical properties of azo dye (1.8-Dihydroxynaphthalene-3,6-

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disulfonic acid -[2-(4-Azo)]-N-(5-methyl-3-isoxazolyl) benzenesulfonamide) film prepared by spray pyrolysis method onto BK7 glass substrate by using spectrophotometer

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measurements of the absorbance, transmittance and reflectance to determine the type of optical transition responsible for optical absorption. Also we have investigated the nonlinear

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optical properties of the azo dye solution sample using thermal lens technique and optical

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switching based on thermal lens (TL).

2. Experimental

2.1. Preparation of the azo dye

The azo dye (1.8-Dihydroxynaphthalene-3,6-disulfonic acid -[2-(4-Azo)]-N-(5-

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methyl-3-isoxazolyl) benzenesulfonamide) was prepared by a method similar to that described by Fox [30]. 6 mM (1.5197 g) of the sulfamethoxazole (C10H11N3O3S) was dissolved in 2 ml of concentrated HCl then, 10 ml of distilled water was added. 0.456 g of NaNO2 was dissolved in about 5ml of distilled water. Diazonium salt was prepared by adding sodium nitrite solution previously prepared to cold solution of amine. 6 mM (2.4017 g) of chromotropic acid disodium salt dehydrate was dissolved in distilled water with the 3

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addition of a solution of 8 gm of sodium hydroxide of 100 ml of distilled water. The dye was kept in a refrigerator for 24 h, then the prepared dye was neutralized by the addition of dilute hydrochloric acid to convert the azo dye from the sodium salt formula to the hydrogenic one. The product was recrystallized, yield is blood red azo dye was 94%. The melting point of the

and UV spectra, with spectral resolution of the order of 0.1 nm.

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dye was below 300 °C. The azo dye has been characterized by the elemental analysis, the IR

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The IR spectrum of the prepared dye as shown in Fig1(b) . As could be seen from

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Fig.1 the spectrum is characterized by a broad and strong band at (3450 ) cm-1 which could be attributed to the hydrogen bonded hydroxy1 group . These bands obscures relatively

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weaker bands that are expected for the NH bands which are ordinarily occurs within the same region. The elemental analysis of C20H16N4O11S3 calculated: C 41.09, H 2.76,N 9.58 ;

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found :C 41.75, H 2.25, N 10.15. The chemical structure and molecular formula of the azo

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dye are shown in Fig 1(a).

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(a)

(b)

Fig. 1. (a) The chemical structure and molecular formula and(b) IR-spectrum of azo dye.

The stretching vibration of the O=H groups appeared in the region of (3448.49) cm-1 while the one belonging to the N=H group supposed to overlapped with H-O bond at (3448.49) cm-1. The stretching vibration band of C=N appeared at (1616.24) cm-1 while the 4

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one belonging to the C=C bond of the aromatic structure appeared at (1496.66) cm-1. The azo group band (N=N) appeared at (1461.94) cm-1. At last the bending vibration of the O=H bonding appeared at (829.33) cm-1. 2. 2. Film preparation

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The spray pyrolysis method used here is basically a chemical deposition method in which fine droplets of the desired material are sprayed onto a heated substrate. Continuous

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films are formed on the hot substrate by thermal decomposition of the material droplets.

The azo films were deposited onto BK7 glass slides, chemically cleaned, using the

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spray pyrolysis method at 170 oC substrate temperature. Concentration of 0.2 mM of azo dye

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in dimethylsulfoxide (DMSO) solvent was used for all the films. The nozzle to substrate distance was 30 cm and during deposition, solution flow rate was held constant at 2 ml/min.

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The substrate temperature was measured using an iron-constantan thermocouple. The thickness of the azo dye film was measured by weight difference method using a sensitive

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microbalance is found to be 2.7 µm.

The optical measurements of azo dye film were carried out at room temperature using

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Cecil ReflectaScan Reflectance Spectrophotometer CE 3055 in the wavelength range (300 – 900) nm. The substrate absorption is corrected by introducing an uncoated cleaned BK7 glass substrate in the reference beam. 2. 3. Surface analysis

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Characterization of surface topography is important in optical devices. In general, it

has been found that diffusion transmission increases with average roughness. Roughness parameters have important applications in linear and nonlinear optics such as linear electrooptical effect, optical filters and optical storage devices. The surface morphology of the azo dye film is characterized by image processing using Origin Lab program. It is employed to simulate an optical procedure to measure surface roughness. The surface profile of the azo 5

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dye film is displayed in Figs. (2-3). As can be seen, two typical morphological features are recognized readily by visual inspection of Figs. (2-3). The first is that the granular features of various scales exist in the film and are distributed almost evenly in some ranges. In addition, the granular features possess different irregular shapes, sizes, and separations. No obvious

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aggregation was observed in the sample. Table.1 shows statistical calculation of film

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thickness.

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Fig. 2. Three-dimensional microscopic image surface profile scan of azo dye film.

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Fig. 3. One-dimensional microscopic image surface profile scan of azo dye film. Inset is the histogram curve of the azo dye film surface.

Table 1. The statistical values of the film thickness (µm) using Origin Lab program. Mean Standard Deviation Minimum Median Maximum 2.706

0.16649

2.16832

2.702

3

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3. Results and Discussions 3.1. Determination of the optical properties of the azo dye film The optical absorbance (A), transmittance (T) and reflectance (R) spectra in the (300-900) nm wavelength range for the azo dye film are depicted in Figs. (4,5). A close examination of the absorption band in the UV region reveals that the Soret (B) band appears

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near 300 nm Fig (4) . The other well-known band of the azo dye, namely Q-band, appears in

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the region 450 and 600 nm. The Q-bands generally interpreted in terms of π-π* excitations between bonding and anti-bonding molecular orbital while the Soret(B) band involves π-d

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transition since absorption occurs near 300 nm. The maximum absorption observed at wavelength region (450-600 nm) then it decreases to zero at wavelength >750 nm. The

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absorption edge of the film occurs at wavelength 620 nm corresponding to a photon energy

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(2 eV). The transmittance spectrum increases in the wavelength range (550-730 nm) and the curve reaches saturation above 730 nm and the average transmittance of the film is 93%. The

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reflectance decreases in the wavelength range (300-325 nm) and gradually rises until it reaches its maximum value of 10.5% at 450 nm. At wavelength >450 nm the reflectance

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decreases rapidly and approaches 5% around 820 nm.

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Fig. 4. The optical absorbance (A) spectrum vs. wavelength of the azo dye film.

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Fig. 5. Transmittance (T) and reflectance (R) spectral vs. wavelength of the azo dye film.

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3.2. Determination of optical constants

The relation between the optical band gap energy, absorption coefficient and energy

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(hv) can be written as[31]:

hv  B(hv  E g ) m

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(1)

where  is the absorption coefficient , E g the band gap energy, constant B is different for

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different transitions, ( hv ) is energy of photon where h is Planck’s constant and v is the frequency of the incident radiation. The magnitude of the exponent m characterizes the type

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of transition, and takes the values 1/2, 3/2, 2 and 3 for direct, allowed forbidden, indirect allowed and indirect forbidden transitions respectively. The absorption coefficient,  , is given by [32]

 1  (1  R) 2 (1  R) 4 ln    R2  2 d  2T 4T 

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

(2)

where d is the thickness of the sample. To understand the nature of energy band gap transition in this material, a graph of ln(hv) vs ln( hv  Eg ) is obtained for the case of the sample as shown in Fig (6) . The plot in the figure

is a straight line, the slope of which gives m =3. This confirms that the transition is a forbidden indirect transition in these materials. When a graph is plotted between (hv)1/ 3 8

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and hv , the result is the curve shown in Fig (7) . By extrapolating of the straight parts of the curve to meet the hv axis, the intersection points gives the band gap energies of the sample as it is shown in the Fig.7. The two gaps energies are Eg1=1.73 eV and Eg2=2.88 eV are

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belong to the Q and Soret (B) bands respectively.

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Fig. 6. Plot of ln(hv) vs ln( hv  E g ) of the azo dye film.

Fig.7. Plot (hv)1/ 3 as a function of photon energy of the azo dye film.

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The refraction index of the azo dye film, n, is given by the following relation [33]

1 R 4R n( ) (  k2) 2 1 R (1  R)

(3)

where k   / 4 is the extinction coefficient, its dependence on λ is shown in Fig (8). It can be seen that the refractive index has a maximum value of 1.95 at wavelength 450 nm as shown in the Fig.8, which is due to interactions takes place between photons and electrons. 9

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Fig. 8. Plot of refractive index, n, (dotted line) and extinction coefficient, k,(solid line)

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as function of wavelength of the azo dye film.

The refractive index changes with the variation of the wavelength of the incident light beam

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due to these interactions, i.e. the optical loss caused by absorption and scattering, which

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decreases the amplitudes of the transmission intensity oscillations at shorter wavelengths. The behavior of refractive index is due to behavior of the reflectance.

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The optical conductivity,  opt , is a measure of frequency response of material when irradiated with light which is determined using the following relation[34]

 opt 

nc 4

(4)

where c is the light velocity.

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The electrical conductivity,  e , can be estimated using the following relation [35]

e 

2 opt

(5)



where λ is the light wavelength. The high magnitude of optical conductivity (1013 sec-1) confirms the presence of very high photo-response of the film. The increase of optical conductivity at high photon energies is due to the high absorbance of azo dye film and may be due to electron excitation by 10

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photon energy. The variation of optical and electrical conductivities as a function of photon energy are plotted in Fig (9) . It is seen that the electrical conductivity decreases with increasing photon energy. The high value of electrical conductivity (105 Ω.cm)-1 indicates

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the semiconducting nature of the material .

Fig. 9. Optical ,  opt , (solid line) and electrical,  e ,(dotted line) conductivities as a

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function of photon energy for azo dye film.

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The real,  1 , and imaginary,  2 , parts of the dielectric constant are determined from the following relations [36,37]:

1  n 2  k 2

(6)

 2  2nk

(7)

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Fig (10) shows the real and imaginary parts of dielectric constant as a function of

photon energy. They have two peaks at 2.55 eV and 2.4 eV respectively ; the values of the real part of dielectric constant are higher than imaginary ones.

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Fig.10. Imaginary ,  2 , (dotted line) and real ,  1 ,(solid line) of the dielectric constant as a function of photon energy. 3.3. Thermal lens and optical switching

When a beam having a Gaussian intensity distribution illuminate a sample, part of

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the incident radiation is absorbed by the sample and a subsequent nonlinear decay of excited

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population result in local heating of the medium. The temperature distribution in the medium will be the same as the profile of the photo inducing beam and hence a refractive index

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gradient is created in the medium. Due to this modification in refractive index, the medium mimics a lens called thermal lens (TL) [38]. The thermal lens generally has negative focal length which causes beam divergence and the signal detected as a time dependence decreases in power at the center of the photo inducing beam at the far field with the aid of another

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beam called the probe beam [39]. If the incident intensity on axis is I(0), the variation of the probe beam intensity on axis I(t) can be written as follows [40]:      2mV 1 I (t )  I (0) 1  tan ( ) t  2 [(1  2m) 2  V 2 ]( c )  1  2m  V 2  2t  

2

(8)

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In which m  ( V 

p ) ;  p and e are the probe and photo inducing beams radii at the sample ; e

z1 ; z1 is the distance between the sample and the waist of the probe beam and z c is the zc

confocal distance of the probe beam, t c is the characteristic TL time constant

 e2 4D

,D 

k is the thermal diffusivity , k is the thermal conductivity,  is the sample C P

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(

density and C P is the specific heat ) [41]. Pe Leff dn ) k p dT

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  (

(9)

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 is the optical absorption coefficient at the photo inducing wavelength ( e ) ,

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Leff  (1  e L ) /  is the effective sample thickness, L it’s thickness,  p is the probe beam wavelength and dn / dT is the thermo-optic coefficient.

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The transient measurements were carried out using the mode matched dual beam (photo inducing and probe) near collinear geometry [42] shown in Fig (11). A solid state cw laser

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(  p  635 nm ) was used as the probe beam and an solid state cw laser ( e  532 nm) TTL

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modulated as the photo inducing beam was used. The photo inducing and probe beams radii at the sample were measured as e  38.56 m and  p  0.5 mm , respectively. The TTL modulation of pump beam allowed for time-resolved measurement. The absorption of photo inducing beam generate the TL heat profile and induced a phase shift  proportional to  .

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The probe and photo inducing beams powers were respectively 1 mW and 35 mW . The TL developed over period of time governed by the rise time of the photo inducing exciting beam and also characteristic of the thermal time constant of the medium. During this time, if the probe beam is allowed to pass the irradiated region and observes the spot size at the far field a hollow disc appeared in the central part of the beam an indication of the occurrence of thermal lens. Fig. 12 shows the relation of normalized thermal lens signal calculated using 13

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equation (9) via Matlab program, where  and t c are obtained. Thermo-optic coefficient, dn / dT , and the effective nonlinear refractive index, n2, caused by a phase shift due to the

thermal lens effect, can be estimated by [43,44] dn 2 n2  dT 4k

(10)

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Table .2 gives the various parameters calculated and used in the fitting shown in Fig(12),

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together with the effective nonlinear refractive index , n2, and the thermo-optic coefficient , dn / dT . Fig (13) shows the temporal progress of the probe beam spot size (TTL frequency

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of excitation beam =300 mHz). A small hole appears after 350 msec suddenly in the spot size

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which grew in size as time lapse and reaches full size after another 500 msec then it dies-out and disappear at time ≤ 950 msec.

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The pump probe experiment can be utilized in the demonstration of optical switching which is based on linear and nonlinear propagation which may be explained as follows:

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The cw probe beam passes through the sample, the output intensity is in the switch-on states because of the linear propagation and higher transmittance. When the sample is pumped by

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the strong, TTL modulated, laser beam the nonlinear propagation dominates so that output intensity would be switched off. Fig (14) shows an oscilloscope trace of transient optical switching (below) together with the input TTL modulated pump signal (above).

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Table .2: Various parameters calculated and used in the fitting of TL signal and nonlinear

Solvent

DMSO

parameters.

k (W m−1

α (cm-

tc

K−1)

1

)

(ms)

0.1567

16.09

3.56

θ (rad)

0.7156

n2

dn/dT (K-

(cm2/Watt)

1

8.13×10-8

2.13×10-6

D (cm2/s)

) 10.44×104

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Photo inducing Laser

Fig.11. Schematic diagram of the thermal lens experimental apparatus, where M’s are

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mirrors, P’s are photodetectors and L’s are convergent lenses. The angle between the

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excitation and probe beams is indicated by α = 5o.

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Fig.12. Typical normalized thermal lens signal for a probe beam as a function of time (dots), the solid line corresponds to the data fitting to equation (8) leaving θ and tc as adjustable parameters. The values obtained were θ= (0.7156 ±0.01243) and tc= (3.56 ± 0.057) ms.

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Fig.13. A photograph show the temporal progress of probe beam spot size for one second interval .

Fig.14. Optical switching effect :pump beam ( upper trace) and probe beam (lower trace).

The measured switch-on time ≤100 ms using TTL modulated laser input beam in the

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studied material is comparable to that measured in 2-(2’-hydroxyphyenyl)benzoxazole [11]. Conclusions

The reflectance spectra of azo dye film prepared by spray pyrolysis method on BK7 \ glass substrates are studied. The complex dielectric function and optical parameters of the film has been obtained. The absorption spectra show that the film has a broad and strong absorption band in the region of 450–600 nm. The refractive index has anomalous behavior 16

Page 16 of 40

in the wavelength range 420–600 nm, this behavior is due to the nature of the sharp absorption of dye material that leads to an electronic transmission at the absorption edge of 2eV. The optical gap energy was estimated from absorption coefficient. The optical transition responsible for optical absorption found to be forbidden indirect transition with

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optical gap energies of Eg1=1.73 eV and Eg2=2.88 eV for azo dye sample. We have reported the nonlinear optical properties of azo dye solution obtained using thermal lens technique

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under cw laser photo inducing at 532 nm. The observed effective nonlinearities were large

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and negative in nature. The reported nonlinearities are primarily thermal in nature owing to the cw excitation. The effective thermal nonlinear refractive index, n2, and thermo-optic

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coefficient, dn/dT has been measured for the azo dye solution. The thermal lens effect was utilized to demonstrate all optical switching. Optical switching based on TL experiment is

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ed

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recorded in azo dye solution.

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References [1] M. Yin, H. P. Li., S. H. Tang , W. Ji, Determination of nonlinear absorption and

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refraction by single Z-scan method, Appl. Phys. B 70 92 (2000) 587-591. [2] P. N. Prasad, J. D. Williams, Introduction to Nonlinear Optical Effects in Molecules

cr

and Polymers, New York, Wiley, 1992.

[3] J. L. Bredas, C. Adant, P. Tackx, A. Persoons, B. M. Pierce, Third-Order Nonlinear

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Optical Response in Organic Materials: Theoretical and Experimental Aspects, Chem.

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Rev. 94 (1994) 243-278.

[4] D. Dorranian, Y. Golian, A. Hojabri, Investigation of nitrogen plasma effect on the

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nonlinear optical properties of PMMA, J. Theor. & Appl. Phys. 1 (2012) 1-8 . [5] A. G. Chen, D. J. Brady, Real-time holography in azo-dye-doped liquid crystals, Opt.

ed

Lett. 17 (1992) 441-443.

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ip t

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[20] K. Driesen, D. Moors, J. Beeckman, K. Neyts, C. Groller-Walrand, K. Binnemans, Near –infrared luminescence emitted by an electrically switched liquid crystal cell, J. Lumin., 127 (2007) 611-615. [21] Z. Zhigang, Yujun Zhang,Analysis of optical switching in a Yb3+-doped fiber Bragg

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determined using dual beam thermal lens method, Spectrochimica Act A 60 (2004) 10771083. [40]A.Lopez-Calvo,Vibrational spectroscopy in cryogenic solutions: Application of thermal lensing and Fourier transform techniques to the study of molecular C-H overtone

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Figure captions

Fig. 1. (a) The chemical structure and molecular formula and(b) IR-spectrum of azo dye. Fig. 2. Three-dimensional microscopic image surface profile scan of azo dye film.

22

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Fig. 3. One-dimensional microscopic image surface profile scan of azo dye film. Inset is the histogram curve of the azo dye film surface. Fig. 4. The optical absorbance (A) spectrum vs. wavelength of the azo dye film. Fig. 5. Transmittance (T) and reflectance (R) spectral vs. wavelength of the azo dye film.

Fig.7. Plot (hv)1/ 3 as a function of photon energy of the azo dye film.

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Fig. 6. Plot of ln(hv) vs ln( hv  E g ) of the azo dye film.

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Fig. 8. Plot of refractive index, n, (dotted line) and extinction coefficient, k,(solid line) as

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function of wavelength of the azo dye film.

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Fig. 9. Optical ,  opt , (solid line) and electrical,  e ,(dotted line) conductivities as a function of photon energy for azo dye film.

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Fig.10. Imaginary ,  2 , (dotted line) and real ,  1 ,(solid line) of the dielectric constant as a function of photon energy.

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Fig.11. Schematic diagram of the thermal lens experimental apparatus, where M’s are mirrors, P’s are photodetectors and L’s are convergent lenses. The angle between the

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excitation and probe beams is indicated by α = 5o. Fig.12. Typical normalized thermal lens signal for a probe beam as a function of time (dots), the solid line corresponds to the data fitting to equation (8) leaving θ and tc as adjustable parameters. The values obtained were θ= (0.7156 ±0.01243) and tc= (3.56 ± 0.057) ms.

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

Fig.13. A photograph show the temporal progress of probe beam spot size for one second interval . Fig.14. Optical switching effect :pump beam ( upper trace) and probe beam (lower trace).

23

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Table

Table 1 Mean

0.16649

Minimum

Median

Maximum

2.16832

2.702

3

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2.706

Standard Deviation

Page 39 of 40

Table

Table 2 k (W m−1 K−1)

α (cm-1)

tc (ms)

θ (rad)

n2 (cm2/Watt)

dn/dT (K-1)

D (cm2/s)

DMSO

0.1567

16.09

3.56

0.7156

8.13×10-8

2.13×10-6

10.44×10-4

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Solvent

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