Aggregation induced convertible third-order nonlinear optical absorptions of the phenoxazinium containing films prepared by sol-gel method

Article abstract of DOI:10.1016/j.dyepig.2014.09.022

The preparation and optical properties of phenoxazinium dye containing optical films by a sol-gel method are reported. The monomer of the phenoxazinium dye substituted with a hydroxyl group, prepared from 3-methoxyaniline by a five-step sequence, can be directly converted to the sol-gel precursor. The preparation and optical properties of phenoxazinium dye containing optical films are reported by in situ sol-gel spin coating with different mole ratios of the precursor to tetraethylorthosilicate. The UV-visible absorption spectra of the films were recorded and the dye aggregation phenomena were discussed. The third-order nonlinear optical properties of the films were measured by a picosecond Z-Scan method at 532 nm. The results indicate that the third-order nonlinear optical absorptions of the films are turned from the reverse saturation absorption with lower dye doping ratios to saturation absorption with higher doping ratios, which induced by the dye aggregation.

Full text of DOI:10.1016/j.dyepig.2014.09.022

Dyes and Pigments 113 (2015) 496e501
Contents lists available at ScienceDirect
Dyes and Pigments
journal homepage: www.elsevier.com/locate/dyepig
Aggregation induced convertible third-order nonlinear optical
absorptions of the phenoxazinium containing films prepared by
solegel method
,
Fei Zhang a, Jia-Tao Miao a, Yu Fang b, Ru Sun a *, Xiao-Zhi Guo a, Ying-Lin Song b,
, c, *
Jian-Feng Ge a
a College of Chemistry, Chemical Engineering and Material Science, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow
University, 199 Ren'Ai Road, Suzhou 215123, China
b School of Physical Science and Technology, Soochow University, 1 Shizi Street, Suzhou 215006, China
c Jiangsu Key Laboratory of Medical Optics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 13 July 2014
Received in revised form
10 September 2014
Accepted 13 September 2014
Available online 20 September 2014
The preparation and optical properties of phenoxazinium dye containing optical films by a solegel
method are reported. The monomer of the phenoxazinium dye substituted with a hydroxyl group,
prepared from 3-methoxyaniline by a five-step sequence, can be directly converted to the solegel pre-
cursor. The preparation and optical properties of phenoxazinium dye containing optical films are re-
ported by in situ solegel spin coating with different mole ratios of the precursor to
tetraethylorthosilicate. The UVevisible absorption spectra of the films were recorded and the dye ag-
gregation phenomena were discussed. The third-order nonlinear optical properties of the films were
measured by a picosecond Z-Scan method at 532 nm. The results indicate that the third-order nonlinear
optical absorptions of the films are turned from the reverse saturation absorption with lower dye doping
ratios to saturation absorption with higher doping ratios, which induced by the dye aggregation.
© 2014 Elsevier Ltd. All rights reserved.
Keywords:
Optical film
Solegel method
Phenoxazinium
Absorption spectrum
Third-order NLO property
Dye aggregation
1. Introduction
crucial because several key requirements must be satisfied such as
high optical and thermal stability, excellent compatibility, and
Functional dyes containing optical films have great importance
for application [1e8]. The optical films are usually prepared by spin
coating of the polymers from functional monomers [9e12], func-
tional dye doped polymers [13e15] and solegel hybrid inorganic-
organic materials [16e20]. The in situ solegel spin coating films
have attracted much attention because of their linkage reaction
between the solegel precursors and the glass [21e24]. Generally,
the preparation of functional dye containing solegel materials in-
volves two distinct steps: the chromophore was covalently bonded
onto an alkoxysilane, and an amorphous silica network was pre-
pared through hydrolysis and condensation of the alkoxysilane dye
[25e27]. In the hybrid system, the choice of the chromophores is
possibility of chemical functionalization for coupling.
In previous work, phenoxazinium and phenothiazinium chloride
were found as new third-order nonlinear optical (NLO) candidates
with good thermal stability, excellent solubility, high third-order
NLO susceptibility (10ꢀ11 esu) and second hyperpolarizability
(10ꢀ29 esu) in acetonitrile solution [28,29]. The third-order NLO
properties of these dyes doped with poly(methyl methacrylate)
(PMMA) in films can be adjusted from the reverse saturable ab-
sorption to the saturable absorption with the increasing dye content
[30,31]. Compared to the films doped with PMMA, films prepared
by the solegel method are more stable due to their reaction with
the glass surface. To improve the stability of the optical film, the
precursors with a hydroxyl group was synthesized with phenox-
azinium as the functional parent structure in this paper. The solegel
precursors were prepared through a bond forming reaction be-
tween 3-isocyanatopropyltriethoxysilane and the heteroaromatic
chromophore 3-(diethylamino)-7-((2-hydroxyethyl)(methyl)amino)
phenoxazin-5-ium perchlorate; the homogeneous hybrid films
were obtained by spin coating of the alkoxysilane dye. The design
* Corresponding authors. College of Chemistry, Chemical Engineering and Ma-
terial Science, Collaborative Innovation Center of Suzhou Nano Science and Tech-
nology, Soochow University, 199 Ren'Ai Road, Suzhou 215123, China. Tel.: þ86 (0)
512 6588 4717; fax: þ86 512 6588 0367.
E-mail addresses: sunru924@hotmail.com (R. Sun), ge_jianfeng@hotmail.com
(J.-F. Ge).
http://dx.doi.org/10.1016/j.dyepig.2014.09.022
0143-7208/© 2014 Elsevier Ltd. All rights reserved.

F. Zhang et al. / Dyes and Pigments 113 (2015) 496e501
497
and synthesis of the structure as well as linear and third-order NLO
properties of the resulting films are discussed in detail.
atmosphere for 1 h, and then 2-iodoethanol (16.50 g, 96.2 mmol)
was added to the reaction. After the mixture was allowed to 60 ꢂ
C
and stirred for 48 h, water (80 mL) was added to the reaction, and
the solution was extracted with ethyl acetate (40 mL ꢁ 5). The
organic layer was combined and washed with brine (15 mL ꢁ 3) and
dried over MgSO4. The solvent was removed by evaporation to
obtain the crude product, which was purified by column chroma-
tography (n-hexane/ethyl acetate ¼ 3:1) to give compound 3. Pale
2. Experimental section
2.1. Materials
All reagents and solvents (analytical grade) were purchased
from TCI Development Co., Ltd. (Tokyo, Japan) or Sinopharm
Chemical Reagent Co., Ltd. (Shanghai, China) and used directly.
Chromatography was performed with silica gel (300e400 mesh).
The quartz glass (25 ꢁ 25 ꢁ 1 mm3) was sequentially washed with
distilled water, acetone and ethanol in an ultrasonic bath.
yellow oil, yield: 50.8%; 1H NMR (400 MHz, DMSO-d6)
d 7.04 (t,
J ¼ 8.4 Hz, 1H, AreH), 6.29 (d, J ¼ 8.2 Hz, 1H, AreH), 6.20e6.18 (m,
2H, 2 ꢁ AreH), 4.67 (t, J ¼ 4.9 Hz,1H, OH), 3.70 (s, 3H, OCH3), 3.53 (q,
J ¼ 5.7 Hz, 2H, CH2), 3.42e3.34 (m, 2H, CH2), 2.90 (s, 3H, CH3);
HRMS(ESIþ) m/z: calcd for [C10H16NO2]þ: 182.1181, found:
[M þ Hþ]þ 182.1176.
2.2. Instruments
2.3.3. 2-((3-Methoxy-4-nitrosophenyl)(methyl)amino)ethanol (4)
A mixture of 3 (16.00 g, 88.3 mmol) and 36% HCl (35.80 g,
353.4 mmol) in H2O (3.0 mL) was stirred in an ice bath. NaNO2
(7.31 g, 106.0 mmol) was slowly added to the mixture within
60 min; then the resulting mixture was stirred in an ice bath for 1 h.
The reaction was adjusted to pH 9.0 by K2CO3 powder. The solid was
ultrasonicated in Et2O and filtrated to give nitroso compound 4.
Green powder, yield: 64.7%; mp: 127.9e128.9 ꢂC; 1H NMR
UVevisible spectra were recorded on a Shimadzu UV-3600
spectrometer. 1H NMR and 13C NMR spectra were recorded on a
Varian 300 or 400 MHz spectrometer. High resolution mass spectra
were recorded on a Finnigan MAT 95 mass spectrometer (ESIþ). The
thickness of the films was obtained by a Hitachi S-4700 scanning
electron microscope (SEM). Atomic force microscope (AFM) images
were tested with a Bruker dimension icon system.
The third-order NLO properties were measured by the Z-scan
technique [32]. An Nd:YAG 532 nm laser (EKSPLA) with a pulse
width of 21 ps (fwhm) and repetition rate of 10 Hz was used for
picosecond Z-scan measurements.
(400 MHz, CD3OD)
d
6.82 (d, J ¼ 9.7 Hz, 1H, AreH), 6.43 (d,
J ¼ 9.6 Hz, 1H, AreH), 6.30 (s, 1H, AreH), 4.10 (s, 3H, OCH3), 3.80 (t,
J ¼ 5.2 Hz, 2H, CH2), 3.72 (t, J ¼ 5.1 Hz, 2H, CH2), 3.26 (s, 3H, CH3);
HRMS(ESIþ) m/z: calcd for [C10H15N2O3]þ: 211.1083, found:
[M þ Hþ]þ 211.1077.
2.3. Synthesis
2.3.4. 3-(Diethylamino)-7-((2-hydroxyethyl)(methyl)amino)
phenoxazin-5-ium perchlorate (5)
2.3.1. N-(3-methoxyphenyl)formamide (1) and 3-methoxy-N-
methylaniline (2)
Compounds 1 and 2 were synthesized using reported methods
[33,34].
The mixture of 3-(diethylamino)phenol (1.34 g, 8.5 mmol) and
90% i-PrOH, 10% water (20 mL) was stirred at 70 ꢂC in a 50 mL two-
neck bottle with distilling apparatus filled with argon. A suspended
solution of 4 (1.78 g, 8.5 mmol) and 72% perchloric acid (1.22 g,
8.5 mmol) in 90% i-PrOH (20 mL) were injected with syringe to the
above mixture in four portions during 45 min. The temperature
rose to reflux. When about 20 mL solvent was distilled out, 90% i-
PrOH (20 mL) was added to the reaction mixture; this procedure
was repeated three times during 3e4 h. The dark blue solution was
evaporated and the residue was purified by column chromatog-
raphy with silica gel, eluting by CHCl3/MeOH from 10:1 to 10:3 (v/v)
to obtain 5. Dark green powder, yield: 67.3%; mp: 197.3e199.5 ꢂC;
3-Methoxyaniline (11.08 g, 90.0 mmol) and formic acid (150 mL)
was heated at 120 ꢂC overnight. The reaction was cooled to room
temperature, saturation NaHCO3 solution was added to make the
mixture neutral. Then, the solution was extracted with ethyl ace-
tate. The organic layer was combined and washed with brine and
dried over MgSO4. The solvent was removed by evaporation to
obtain the crude product, which was purified by column chroma-
tography (n-hexane/ethyl acetate ¼ 2:1) to give compound 1. Yield:
73.6%;1H NMR (300 MHz, DMSO-d6)
d 10.16 (s, 1H), 8.25 (s, 1H), 7.22
(t, J ¼ 8.1 Hz, 1H), 7.10 (d, J ¼ 7.9 Hz, 1H), 6.66 (d, J ¼ 7.0 Hz, 1H), 3.73
(s, 3H); HRMS(ESIþ) m/z: calcd for [C8H10NO2]þ: 152.0703, found:
[M þ Hþ]þ 152.0706.
1H NMR (300 MHz, CD3OD)
d
7.79 (d, J ¼ 10.0 Hz, 1H, AreH), 7.77 (d,
J ¼ 9.5 Hz, 1H, AreH), 7.44 (d, J ¼ 12.0 Hz, 1H, AreH), 7.40 (dd,
J ¼ 10.0 Hz, 1H, AreH), 7.01 (s, 1H, AreH), 6.97 (d, J ¼ 1.8 Hz, 1H,
AreH), 3.89 (br, 4H, 2 ꢁ CH2), 3.78 (q, J ¼ 7.1 Hz, 4H, 2 ꢁ CH2), 3.42
(s, 3H, CH3), 1.35 (t, J ¼ 7.1 Hz, 6H, 2 ꢁ CH3); 13C NMR (75 MHz,
LiAlH4 (5.03 g,132.3 mmol) and dry ether (100 mL) was added to
a 250 mL round-bottomed flask. And compound 1 (10.0 g,
66.16 mmol) dissolving in dry ether (20 mL) was slowly added to
the stirring solution at 0 ꢂC. The mixture was gradually raised to
room temperature and stirred for 6 h. Then, saturation NH4Cl so-
lution was added to the mixture and the solution was extracted
with ether. The organic layer was combined and washed with brine
and dried over MgSO4. The solvent was removed by evaporation to
obtain the crude product, which was purified by column chroma-
tography (n-hexane/ethyl acetate ¼ 3:1) to give compound 2. Yield:
CD3OD)
d 159.61, 157.95, 151.02, 150.59, 135.94, 135.72, 135.53,
135.08, 118.92, 98.01, 97.55, 60.59, 56.85, 47.92, 41.13, 13.24;
HRMS(ESIþ) m/z: calcd for [C19H24N3O2]þ: 326.1869, found: [M-
ClOꢀ4 ]þ 326.1869.
2.3.5. 3-(Diethylamino)-7-((2-(1-imino-4-(triethoxysilyl)
butylperoxy)ethyl)(methyl)amino)phen-oxazin-5-ium perchlorate
(6)
65.6%; 1H NMR (300 MHz, DMSO-d6)
d
6.96 (t, J ¼ 8.0 Hz, 1H), 6.12
To the mixture of compound 5 (425.9 mg, 1.0 mmol) and dry
CH2Cl2 (30 mL) in flask, 3-isocyanatopropyltriethoxysilane
(247.4 mg, 1.0 mmol) and dibutyltin laurate (126.5 mg, 0.2 mmol)
were added. After the reaction mixture was stirred for overnight at
50 ꢂC under a nitrogen atmosphere, the dark blue solution was
evaporated and the residue was purified by column chromatog-
raphy (CH2Cl2/MeOH ¼ 20:1) to give 6. Dark green powder, yield:
(d, J ¼ 4.7 Hz, 2H), 6.06 (d, J ¼ 1.7 Hz, 1H), 5.59 (s, 1H), 3.66 (s, 3H),
2.64 (d, J ¼ 3.7 Hz, 3H); HRMS(ESIþ) m/z: calcd for [C8H12NO]þ:
138.0841, found: [M þ Hþ]þ 138.0913.
2.3.2. 2-((3-Methoxyphenyl) (methyl)amino)ethanol (3)
Compound 2 (12.00 g, 87.5 mmol) was added slowly to a solu-
tion of 60% sodium hydride (3.50 g, 87.5 mmol) in DMF (200 mL).
The solution was stirred at room temperature under nitrogen
41.8%; mp: 142.6e144.0 ꢂC; 1H NMR (400 MHz, CDCl3)
d
7.76 (s, 1H,
AreH), 7.74 (s, 1H, AreH), 7.24 (br, 1H, AreH), 7.22 (br, 1H, AreH),

498
F. Zhang et al. / Dyes and Pigments 113 (2015) 496e501
Scheme 1. Synthetic route of the monomer of the phenoxazinium dye with hydroxyl group.
6.99 (s, 1H, AreH), 6.95 (s, 1H, AreH), 5.40 (s, 1H, NH), 4.38 (t,
J ¼ 4.9 Hz, 2H, CH2), 3.97 (t, J ¼ 4.9 Hz, 2H, CH2), 3.82e3.70 (m, 10H,
5 ꢁ CH2), 3.41 (s, 3H, CH3), 3.12 (q, J ¼ 4.0 Hz, 2H, CH2), 1.61e1.54 (m,
2H, CH2), 1.41 (t, J ¼ 7.1 Hz, 6H, 2 ꢁ CH3), 1.26e1.18 (m, 9H, 3 ꢁ CH3),
The solegel precursors a, b, c and d indicate different reaction ratio
of compound 6 to TEOS (1/10, 1/60, 1/100, 1/200 respectively).
2.4.2. Preparation of the organic-SiO2 hybrid films
0.58 (m, 2H, CH2); 13C NMR (75 MHz, CDCl3)
d 157.52,156.43,156.07,
The solegel precursors were filtrated with a syringe through a
149.32, 148.71, 134.79, 134.14, 133.75, 117.71, 116.93, 97.14, 96.70,
61.08, 58.42, 52.81, 47.17, 43.52, 40.63, 23.14, 18.29, 12.99, 7.52, 1.02;
HRMS(ESIþ) m/z: calcd for [C29H45N4O6Si]þ: 573.3108, found:
[M þ Hþ] 573.3088.
0.22 mm filter before use. The films were obtained by spin-coating
at 2000 rpm for 1 min at room temperature, and film a, b, c, and
d indicate the different reaction ratios of compound 6/TEOS (1/10,
1/60, 1/100, 1/200, respectively). All the films were dried in vacuum
at 40 ꢂC for ten hours.
2.4. Preparation of the films
3. Results and discussion
2.4.1. Synthesis of the hybrid solegel materials
Tetraethylorthosilicate (TEOS) was slowly added to a solution of
6 (67.3 mg, 0.1 mmol) in CH3CN (2.0 mL), and then the reaction was
adjusted to pH ¼ 3 with slight excess amount of 72% perchloric acid.
After stirring for 3 days at room temperature, a homogeneous so-
lution (or solegel; a hybrid precursor) was obtained (Scheme 2).
3.1. Synthesis of the phenoxazinium dye with hydroxyl group
The synthesis of the hydroxyl group containing phenoxazinium
dye (5) is shown in Scheme 1. 3-Methoxy-N-methylaniline (2) was
synthesized from m-methoxyaniline by formylation [33] and
reduction reaction [34] according to the reported methods. Then, 2-
((3-methoxyphenyl)(methyl) amino)ethanol (3) was obtained by
alkylation with 2-iodoethanol from compound 2 under basic con-
ditions. The 3-(diethylamino)phenol and nitro compound (4),
which is derivate from compound 3 by nitrosation, can be
condensed to the phenoxazinium dye 5 under acidic conditions.
The hydroxyl group in compound 5 acts as the key reactive func-
tional groups in the next stage. The synthesis of a vinyl terminated
phenoxazinium monomer was attempted; however, the free radical
polymerization of this species failed in all cases. So the in situ sol-
egel method was selected for the preparation of the optical films in
next stage.
Fig. 1. Normalized absorption spectra of films aed and compound 6 in DMF. The re-
action mole ratios of compound 6 to TEOS: film a: 1/10, film b: 1/60, film c: 1/100 and
film d: 1/200.
Scheme 2. Synthetic route of the hybrid material with phenoxazinium chromophore
by solegel method.

F. Zhang et al. / Dyes and Pigments 113 (2015) 496e501
499
Fig. 2. The open-aperture Z-scan signals of the spin coating solegel films (points are tested data and lines are fit curves). The reaction mole ratios of compound 6 to TEOS: film a: 1/
10, film b: 1/60, film c: 1/100 and film d: 1/200.
3.2. Optical properties of the phenoxazinium containing solegel
films
film a was obtained by spin coating at 2000 rpm for 1 min. The
normalized absorptions of the film a and compound 6 in DMF are
shown in Fig. 1. The UVevisible spectrum of film a shows a strong
absorption maximum at 601 nm with a shoulder peak at 671 nm,
while the monomer of the phenoxazinium 6 in DMF has absorption
maximum at 651 nm with a shoulder peak around 600 nm, which is
clearly indicate that the aggregation of the phenoxazinium in film a
leads to the enhancement of the peak at 601 nm [35]. Therefore, the
increasement mole ratios of TEOS for the solegel precursors were
prepared to avoid this aggregation. Film b, c and d were made by the
The in situ solegel procedure is shown in Scheme 2. Compound
6 was synthesized by the reaction of compound 5 with isocyanate,
and subsequently reacted with TEOS under acidic conditions to
form the solegel precursors 7, which can react with the surface of
the quartz glass after spin coating.
The solegel precursors was firstly explored with the 1:10 mol
ratios of compound 6 and TEOS in acetonitrile, the corresponding
Fig. 3. Z-scan data of refractive parts of the spin coating solegel films (points are tested data and lines are fit curves). The reaction mole ratios of compound 6 to TEOS: film a: 1/10,
film b: 1/60, film c: 1/100 and film d: 1/200.

500
F. Zhang et al. / Dyes and Pigments 113 (2015) 496e501
Table 1
The third-order NLO properties of the spin coating solegel films (aed).a
Film
Dye 6/TEOS
Film thickness
(nm)b
Linear
transmission (%)
b
(m wꢀ1
)
n2 (m2 wꢀ1
)
c(3)R (esu)
c(3)I (esu)
(10ꢀ10
c
(3) (esu)
c(3)
/
R
c(3)
g0 (esu)
I
(10ꢀ8
)
(10ꢀ14
)
(10ꢀ9
)
)
(10ꢀ9
)
(10ꢀ31
)
a
b
c
1/10
1/60
1/100
1/200
79
345
759
657
67
50
63
76
ꢀ7.5
ꢀ4.5
2.5
3.30
1.30
0.79
1.10
13.10
3.70
3.98
5.57
ꢀ12.60
ꢀ5.42
5.33
13.20
3.74
4.02
5.89
10.4
6.8
7.5
5.48
1.55
1.67
2.45
d
8.9
19.1
2.9
a
Data were obtained by picosecond Z-Scan at 532 nm with 0.18
Tested by SEM.
mJ.
b
same way as film a with the mole ratios of compound 6 to TEOS to
be 1:60, 1:100 and 1:200, respectively. The absorption intensities of
film b and c are slight higher than film a, while the one of film d is
lower than that of film a (Fig. 1). Meanwhile, the absorption bands
around 600 nm of film b and c are reduced, and the film d shows the
weakest peak at 600 nm. These indicate the increasement of the
TEOS ratios will reduce the dye aggregation in the solegel films.
The Z-scan measurements were carried out using reported
method [30]. Third-order NLO responses of the films a-d are shown
in Fig. 2. The third-order NLO property of film a shows a saturation
absorption (Fig. 2, film a), which is different to the third-order NLO
reverse saturation absorption properties for phenoxazinium dyes in
solution. Considering the above discussed UVevis absorption fea-
tures of film a, the dye aggregation phenomenon would be the
reason for the opposite third-order NLO absorption between their
films and solution. In accordance with expectation, film b and c
show the phenomena of transition from saturation to reverse
saturation absorption, and a reverse saturable absorption is found
in film d. The results indicate the aggregation of phenoxazinium
dyes will influence the third-order NLO properties of their films.
The Z-scan data of refractive parts of the spin coating solegel
films under picosecond laser beam irradiation (0.18 mJ) are shown
in Fig. 3. The nonlinear refractive data were obtained from the ratio
of the closed aperture transmittance divided by the open aperture
transmittance. The valley-to-peak configuration of the curve sug-
gests that the refractive index change is positive, indicating a self-
focusing effect.
The detailed parameters of the NLO properties of the films aed
were collected in Table 1. The films exhibit a larger nonlinear ab-
sorption coefficient (b
up to 10ꢀ8 m wꢀ1) and nonlinear refractive
Fig. 4. The AFM images of the spin coating solegel films. The reaction mole ratios of compound 6 to TEOS: film a: 1/10, film b: 1/60, film c: 1/100 and film d: 1/200.

F. Zhang et al. / Dyes and Pigments 113 (2015) 496e501
501
index (n2 up to 10ꢀ14 m2
diation at 0.18 J. The third-order NLO susceptibility
(aed) are up to 10ꢀ9 esu. As is known, the larger the
w
ꢀ1) under picosecond laser beam irra-
(3) of the films
(3) value, the
[10] Yao Y, Ma YZ, Qin M, Ma XJ, Wang C, Feng XZ. Nhs-ester functionalized pol-
y(pegma) brushes on silicon surface for covalent protein immobilization.
Colloids Surf B Biointerfaces 2008;66(2):233e9.
[11] Grande CD, Tria MC, Jiang G, Ponnapati R, Advincula R. Surface-grafted
polymers from electropolymerized polythiophene raft agent. Macromolecules
2011;44(4):966e75.
[12] Ouyang Q-Y, Chen Y-J, Li C-Y. The fabrication and enhanced nonlinear optical
properties of electrostatic self-assembled film containing water-soluble chiral
polymers. Mater Chem Phys 2012;134(1):80e6.
[13] Tekin S, Yaglioglu HG, Elmali A, Kürüm U, Yanık H, Tekdas¸ DA, et al. The effect
of aggregation on the nonlinear optical absorption performance of indium and
gallium phthalocyanines in a solution and co-polymer host. Mater Chem Phys
2013;138(1):270e6.
[14] Sun S-S, Zhang C, Dalton LR, Garner SM, Chen A, Steier WH. 1,3-bis(dicya-
nomethylidene)indane-based second-order NLO materials. Chem Mater
1996;8(11):2539e41.
[15] Macchi R, Cariati E, Marinotto D, Roberto D, Tordin E, Ugo R, et al. Stable SHG
from in situ grown oriented nanocrystals of [(E)-N,N-dimethylamino-N[prime
or minute]-methylstilbazolium][p-toluenesulfonate] in a PMMA film. J Mater
Chem 2010;20(10):1885e90.
m
c
c
better the NLO properties of the material. And the second hyper-
polarizabilities g0 of the adopted films (a-d) are up to 10ꢀ31 esu.
The surface morphologies of the films were characterized by
atomic force microscope (AFM) images. As can be seen from Fig. 4,
more uniform films were obtained by the solegel method, the
phase separation phenomena in phenoxazinium-TEOS films did not
occur in this case [30,31]. However, the film aggregation phenom-
enon was clearly exhibited from the higher doping ratio. With the
decreasing dye doping ratio, the films became more and more
homogeneous. The results also indicate the solegel method is a
preferred method for film preparation of this type of functional dye.
[16] Kim HK, Kang S-J, Choi S-K, Min Y-H, Yoon C-S. Highly efficient organic/
inorganic hybrid nonlinear optic materials via solꢀgel process: Synthesis,
optical properties, and photobleaching for channel waveguides. Chem Mater
1999;11(3):779e88.
[17] Wang S, Zhao L, Sun J, Cui Z, Zhang D. Preparation of stable second-order
nonlinear optical films by solegel technique. Polym Adv Technol
2011;22(5):759e62.
[18] Gao J, Cui Y, Yu J, Lin W, Wang Z, Qian G. Enhancement of nonlinear optical
activity in new six-branched dendritic dipolar chromophore. J Mater Chem
2011;21(9):3197e203.
[19] Gao J, Cui Y, Yu J, Wang Z, Wang M, Qiu J, et al. Molecular design and synthesis
of hetero-trichromophore for enhanced nonlinear optical activity. Macro-
molecules 2009;42(6):2198e203.
[20] Zhang D, Wang X, Qiao Z-a, Tang D, Liu Y, Huo Q. Synthesis and character-
ization of novel lanthanide(iii) complexes-functionalized mesoporous silica
nanoparticles as fluorescent nanomaterials. J Phys Chem C 2010;114(29):
12505e10.
[21] Cui Y, Qian G, Chen L, Wang Z, Wang M. Hybrid nonlinear optical materials
containing imidazole chromophore through the sol-gel process. Macromol
Rapid Comm 2007;28(20):2019e23.
4. Conclusions
The optical films of the functional dyes are very important for
real application. In this paper, phenoxazinium containing films
were reported by an in situ solegel method. Their absorption
properties and third-order optical properties were evaluated by
UVevisible spectroscopy and Z-scan technology with picosecond
laser beam at 532 nm. The third-order NLO saturation absorption
was found for the higher doping ratio films, while the reverse
saturation absorption was shown in the lower doping ratio films
due to the aggregation of phenoxazinium dye verified by AFM
images. The films containing the phenoxazinium have the larger
third-order NLO susceptibility, which implied the phenoxazinium
dye would be a good candidate for third-order NLO optical material.
[22] Hucknall A, Kim D-H, Rangarajan S, Hill RT, Reichert WM, Chilkoti A. Simple
fabrication of antibody microarrays on nonfouling polymer brushes with
femtomolar sensitivity for protein analytes in serum and blood. Adv Mater
2009;21(19):1968e71.
[23] García O, Sastre R, del Agua D, Costela A, García-Moreno I. New fluorinated
polymers doped with bodipy chromophore as highly efficient and photostable
optical materials. Chem Mater 2006;18(3):601e2.
[24] García-Moreno I, Costela A, Cuesta A, García O, del Agua D, Sastre R. Synthesis,
structure, and physical properties of hybrid nanocomposites for solid-state
dye lasers. J Phys Chem B 2005;109(46):21618e26.
Acknowledgments
The project is supported from the National Natural Science
Foundation of China (51273136) and the Project funded by the
Priority Academic Program Development of Jiangsu Higher Edu-
cation Institutions.
References
[25] Chaumel F, Jiang H, Kakkar A. Solꢀgel materials for second-order nonlinear
optics. Chem Mater 2001;13(10):3389e95.
[1] Sreejith S, Carol P, Chithra P, Ajayaghosh A. Squaraine dyes: a mine of mo-
lecular materials. J Mater Chem 2008;18(3):264e74.
[26] Innocenzi P, Lebeau B. Organic-inorganic hybrid materials for non-linear op-
tics. J Mater Chem 2005;15(35e36):3821e31.
[2] Alicante R, Cases R, Villacampa B, Blasco E. Matrix order influence on the non-
linear optical properties of dispersed chromophore-azopolymer systems.
Macromol Chem Phys 2012;213(7):776e83.
[27] Sanchez C, Lebeau B, Chaput F, Boilot JP. Optical properties of functional
hybrid organiceinorganic nanocomposites. Adv Mater 2003;15(23):1969e94.
[28] Ge J-F, Lu Y-T, Sun R, Zhang J, Xu Q-F, Li N-J, et al. Third-order nonlinear
optical properties of symmetric phenoxazinium chlorides with resonance
structures at 532 nm. Dyes Pigm 2011;91(3):489e94.
[3] Padilha LA, Webster S, Przhonska OV, Hu H, Peceli D, Rosch JL, et al. Nonlinear
absorption in a series of donor-p-acceptor cyanines with different conjugation
lengths. J Mater Chem 2009;19(40):7503e13.
[29] Lu Y-T, Ge J-F, Xu Q-F, Yang Y, Li N-J, Sun R, et al. Third-order nonlinear optical
properties of the phenothiazinium chlorides at 532 nm. Dyes Pigm
2011;89(1):70e5.
[30] Miao J-T, Sun R, Yan B-L, Wu X-Z, Song Y-L, Lu J-M, et al. Adjustable third-
order nonlinear optical properties of the spin coating phenox-
aziniumePMMA films. Mater Chem Phys 2014;147(1e2):232e7.
[31] Sun R, Lu Y-T, Yan B-L, Lu J-M, Wu X-Z, Song Y-L, et al. Third-order nonlinear
optical properties of the poly(methyl methacrylate)-phenothiazinium dye
hybrid thin films. Thin Solid Films 2014;551(0):153e7.
[4] Webster S, Fu J, Padilha LA, Przhonska OV, Hagan DJ, Van Stryland EW, et al.
Comparison of nonlinear absorption in three similar dyes: polymethine,
squaraine and tetraone. Chem Phys 2008;348(1e3):143e51.
[5] Su X, Guang S, Xu H, Yang J, Song Y. The preparation and optical limiting
properties of poss-based molecular hybrid functional materials. Dyes Pigm
2010;87(1):69e75.
[6] Srinivas K, Prabhakar C, Devi CL, Yesudas K, Bhanuprakash K, Rao VJ. Enhanced
diradical nature in oxyallyl derivatives leads to near infra red absorption: a
comparative study of the squaraine and croconate dyes using computational
techniques. J Phys Chem A 2007;111(17):3378e86.
[7] Miao J-T, Wu X-Z, Sun R, Song Y-L, Ge J-F. The third-order nonlinear optical
properties of charge flowable trimethine cyanine with quinolone groups. Dyes
Pigm 2014;105(0):41e6.
[8] Zhang T, Ma N, Yan L, Ma T, Su Z. Theoretical exploration on switchable NLO
response induced by photochromic properties of covalently connected un-
symmetrical spiropyranepolyoxometalate complex. Dyes Pigm 2014;106(0):
105e10.
[32] Niu Y, Song Y, Hou H, Zhu Y. Synthesis, structure, and large optical limiting
effect of the first coordination polymeric cluster based on an {I@[AgI(inh)]6}
hexagram block. Inorg Chem 2005;44(7):2553e9.
[33] Corrie JET, Craik JS, Munasinghe VRN. A homobifunctional rhodamine for la-
beling proteins with defined orientations of a fluorophore. Bioconjugate Chem
1998;9(2):160e7.
ꢀ
[34] Parisel SL, Adrio LA, Pereira AA, Perez MM, Vila JM, Hii KK. Reversal of aryl
bromide reactivity in pd-catalysed aryl amination reactions promoted by a
hemilabile aminophosphine ligand. Tetrahedron 2005;61(41):9822e6.
[35] Jose J, Ueno Y, Burgess K. Water-soluble Nile Blue derivatives: syntheses and
photophysical properties. Chem-Eur J 2009;15(2):418e23.
[9] Xu D, Yu WH, Kang ET, Neoh KG. Functionalization of hydrogen-terminated
silicon via surface-initiated atom-transfer radical polymerization and deriva-
tization of the polymer brushes. J Colloid Interf Sci 2004;279(1):78e87.