**3. Results and discussion**

It should be noticed that previously, we demonstrated [5,6,8] the formation of barrier-free charge transfer pathways, increased dipole moment, and increased specific (per unit vol‐ ume) local polarizability in some organic matrices doped with fullerenes, carbon nanotubes and quantum dots, where the formation of intermolecular complexes predominated over the intramolecular donor–acceptor interaction. The possible schemes of charge transfer between matrix organic molecule donor fragment and different efficient nanosensitizers including the additional graphene and shungites nanostructures are schematically shown in Fig. 4.

Analyzing the Fig.4, one can say that it is necessary to take into account that the charge transfer between matrix organic molecule donor fragment and nanasensitizers can be organ‐ ized due to their high electron affinity energy (for example, electron affinity energy is close to 2 eV for shungites [9], to 2.65 eV for fullerenes [5,8] and to 3.8-4.2 eV for quantum dots [10]) that is more than the ones for intramolecular acceptor fragments (for example, electron affinity energy of COANP acceptor fragment is close to 0.54 eV [11] and to 1.14-1.4 eV for polyimide one [12]). Regarding graphenes it is necessary to take into account the high sur‐ face energy and planarity of the graphenes plane which can provoke to organize the charge transfer complex (CTC) with good advantage too. Regarding the CNTs it should be drawn the attention on the variety of charge transfer pathways, including those along and across a CNT, between CNTs, inside a multiwall CNT, between organic matrix molecules and CNTs, and between the donor and acceptor fragments of an organic matrix molecule.

The second harmonic of pulsed Nd-laser at wave length of 532 nm has been used. The laser energy density has been chosen in the range of 0.005-0.9 J×cm-2. The nanosecond laser re‐ gime with the pulse width of 10-20 ns has been applied. The amplitude-phase thin gratings have been recorded under Raman-Nath diffraction conditions according to which Λ-1 ≥ *d*, where Λ–1 is the inverse spatial frequency of recording (i.e., the period of the recorded gra‐ ting) and *d* is the film thickness. In the experiments the spatial frequency was in the range of

The spectral characteristics have been tested using Perkin Elmer lambda 9 spectrophotome‐ ter. Dynamic features of nanoobjects-doped LC films have been studied via the four-wave mixing technique and the Frederick's scheme one. Atomic force microscopy (AFM) method using equipment of "NT-MDT" firm, "Bio47-Smena" in the "share-force" regime has been applied to analyze the diffraction relief into the solid conjugated nanostructured thin film.

It should be noticed that previously, we demonstrated [5,6,8] the formation of barrier-free charge transfer pathways, increased dipole moment, and increased specific (per unit vol‐ ume) local polarizability in some organic matrices doped with fullerenes, carbon nanotubes and quantum dots, where the formation of intermolecular complexes predominated over the intramolecular donor–acceptor interaction. The possible schemes of charge transfer between matrix organic molecule donor fragment and different efficient nanosensitizers including the additional graphene and shungites nanostructures are schematically shown in Fig. 4.

**Figure 4.** Schematic diagram of possible intermolecular charge transfer domination under intramolecular ones.

Analyzing the Fig.4, one can say that it is necessary to take into account that the charge transfer between matrix organic molecule donor fragment and nanasensitizers can be organ‐

90-150 mm-1.

**3. Results and discussion**

400 Syntheses and Applications of Carbon Nanotubes and Their Composites

**Figure 5.** The rate of release of C70 molecules on heating of systems: (*1*) COANP with 5 wt % of C70 and (*2*) polyimide with 0.5 wt % of C70

It should be noticed that some supporting CTC results for PIs and COANP systems sensi‐ tized with nanoobjects can be presented via mass-spectrometry experiments. It is easy to show the organization of CTC using fullerenes acceptor. Really, the mass spectroscopy data point to the effective CTC formation between fullerene and donor part of PI (triphenyla‐ mine) and between fullerene and the HN group of COANP systems, respectively. For the 5 wt.% C70-COANP film, mass spectrometry curve contains two peaks. The first one at 400 C corresponds to the release rate of fragments with free fullerene masses. The second one is shifted to the temperature range of 520 °C and associated with the decomposition tempera‐ ture of the fullerene-HN group complex. For the 0.5 wt.% C70-PI film, curve contains three peaks. The first one is observed also close to 400 C. The second peak is located at 560 °C and associated with the decomposition of fullerene- triphenylamine complex. It should be no‐ ticed that the melting temperature of these PIs is 700-1000 °C, thus, the third peak at the temperature higher 700 °C corresponds to the total decomposition of PI. Figure 5 presents the mass-spectrometry data.

manifested by a difference in the distribution of diffraction orders along the horizontal and vertical axes (see Fig.6). Thus, the grating displacement takes place in a three dimensional (3D)

Carbon Nanotubes Influence on Spectral, Photoconductive, Photorefractive and Dynamic Properties of the Optical

Some atomic force microscopy data are supported the realization of 3D-media via develop‐ ment of complicated diffraction relief into the solid thin conjugated films after transfer from the reversible regime to the irreversible one. Figure 7 demonstrates this fact. Two types of diffraction replica, namely due to interference of laser beams onto the thin films surface and due to the diffraction of these beams inside the body of the nanostructured media have

Using the obtained results, the nonlinear refraction *n* <sup>2</sup> and nonlinear third order optical sus‐ ceptibility (cubic nonlinearity) χ(3) for all systems have been calculated using a method de‐ scribed in [13,18]. In the current experiments using four-wave mixing technique, the nonlinear refraction coefficient and cubic nonlinearity (third order susceptibility) have been

where *I* – is the irradiation intensity, *n* <sup>o</sup> – is the linear refractive index of the media, *с* – is the

Moreover, it should be remained, that optical susceptibility χ(n), from fundamental point of view, directly connected with the dipole system polarizability (n) via equation (3) written in

*n*<sup>2</sup> =*Δn*i/ *I* (1)

/W and χ(3) = 10–10–10–9 cm3

/erg.

Materials

403

http://dx.doi.org/10.5772/50843

*<sup>χ</sup>* (3)=*n*2*n*0*<sup>c</sup>* / <sup>16</sup>*<sup>π</sup>* <sup>2</sup> (2)

medium formed as a result of the nanostructirization (rather than in a 2D medium).

**Figure 7.** Demonstration of AFM evidence of new 3D-media development.

It was found that these parameters fall within *n* 2 = 10–10–10–9 cm2

estimated via equations (1) and (2):

speed of the light.

the paper [19]:

been presented.

By monitoring the diffraction response manifested in the laser scheme (see Fig.6); it is possi‐ ble to study the dynamics of a photo-induced change in the refractive index of a sample and to calculate via [13] the nonlinear refraction and nonlinear third order optical susceptibility (cubic nonlinearity). An increase in the latter parameter characterizes a change in the specif‐ ic (per unit volume) local polarizability and, hence, in the macroscopic polarization of the entire system.

**Figure 6.** The visualization of the diffraction response in the organic films doped with nanoobjects.

The main results of this study are summarized in the Table 1 (Ref. 5,6,9,14-18) in compari‐ son to the data of some previous investigations. An analysis of data presented in the Table 1 for various organic systems shows that the introduction of nanoobjects as active acceptors of electrons significantly influences the charge transfer under conditions where the intermolec‐ ular interaction predominates over the intramolecular donor–acceptor ones. Moreover, redis‐ tribution of the electron density during the recording of gratings in nanostructured materials changes the refractive index by at least one order of magnitude in comparision to that in the initial matrix. The diffusion of carriers from the bright to dark region during the laser record‐ ing of the interference pattern proceeds in three (rather than two) dimensions, which is manifested by a difference in the distribution of diffraction orders along the horizontal and vertical axes (see Fig.6). Thus, the grating displacement takes place in a three dimensional (3D) medium formed as a result of the nanostructirization (rather than in a 2D medium).

Some atomic force microscopy data are supported the realization of 3D-media via develop‐ ment of complicated diffraction relief into the solid thin conjugated films after transfer from the reversible regime to the irreversible one. Figure 7 demonstrates this fact. Two types of diffraction replica, namely due to interference of laser beams onto the thin films surface and due to the diffraction of these beams inside the body of the nanostructured media have been presented.

**Figure 7.** Demonstration of AFM evidence of new 3D-media development.

mine) and between fullerene and the HN group of COANP systems, respectively. For the 5 wt.% C70-COANP film, mass spectrometry curve contains two peaks. The first one at 400 C corresponds to the release rate of fragments with free fullerene masses. The second one is shifted to the temperature range of 520 °C and associated with the decomposition tempera‐ ture of the fullerene-HN group complex. For the 0.5 wt.% C70-PI film, curve contains three peaks. The first one is observed also close to 400 C. The second peak is located at 560 °C and associated with the decomposition of fullerene- triphenylamine complex. It should be no‐ ticed that the melting temperature of these PIs is 700-1000 °C, thus, the third peak at the temperature higher 700 °C corresponds to the total decomposition of PI. Figure 5 presents

By monitoring the diffraction response manifested in the laser scheme (see Fig.6); it is possi‐ ble to study the dynamics of a photo-induced change in the refractive index of a sample and to calculate via [13] the nonlinear refraction and nonlinear third order optical susceptibility (cubic nonlinearity). An increase in the latter parameter characterizes a change in the specif‐ ic (per unit volume) local polarizability and, hence, in the macroscopic polarization of the

**Figure 6.** The visualization of the diffraction response in the organic films doped with nanoobjects.

The main results of this study are summarized in the Table 1 (Ref. 5,6,9,14-18) in compari‐ son to the data of some previous investigations. An analysis of data presented in the Table 1 for various organic systems shows that the introduction of nanoobjects as active acceptors of electrons significantly influences the charge transfer under conditions where the intermolec‐ ular interaction predominates over the intramolecular donor–acceptor ones. Moreover, redis‐ tribution of the electron density during the recording of gratings in nanostructured materials changes the refractive index by at least one order of magnitude in comparision to that in the initial matrix. The diffusion of carriers from the bright to dark region during the laser record‐ ing of the interference pattern proceeds in three (rather than two) dimensions, which is

the mass-spectrometry data.

402 Syntheses and Applications of Carbon Nanotubes and Their Composites

entire system.

Using the obtained results, the nonlinear refraction *n* <sup>2</sup> and nonlinear third order optical sus‐ ceptibility (cubic nonlinearity) χ(3) for all systems have been calculated using a method de‐ scribed in [13,18]. In the current experiments using four-wave mixing technique, the nonlinear refraction coefficient and cubic nonlinearity (third order susceptibility) have been estimated via equations (1) and (2):

$$m\_2 = \Delta m\_i / I \tag{1}$$

$$
\chi^{(3)} = n\_2 n\_0 c \left/ 16\pi^2 \right. \tag{2}
$$

where *I* – is the irradiation intensity, *n* <sup>o</sup> – is the linear refractive index of the media, *с* – is the speed of the light.

It was found that these parameters fall within *n* 2 = 10–10–10–9 cm2 /W and χ(3) = 10–10–10–9 cm3 /erg.

Moreover, it should be remained, that optical susceptibility χ(n), from fundamental point of view, directly connected with the dipole system polarizability (n) via equation (3) written in the paper [19]:

$$
\alpha \chi^{(\mathfrak{n})} = \alpha^{(\mathfrak{n})} / \upsilon
\tag{3}
$$

In addition, the barrier free charge transfer will be influenced by competition between the diffusion and drift of carriers during the creation of diffraction patterns with various peri‐ ods and, hence, differing charge localization at the grating nodes and antinodes. Indeed, in the case of a nanocomposite irradiated at small spatial frequencies (large periods of record‐ ed grating), a drift mechanism of the carrier spreading in the electric field of an intense radi‐ ation field will moist probably predominate, while at large spatial frequencies (short periods of recorded grating) the dominating process is diffusion. This also naturally accounts for the aforementioned discrepancy of published data on photoinduced changes in the refractive in‐ dex of nanocomposites, greater values of which were observed (see, e.g., data presented in the table for systems doped with CNTs and MIG nanofibers) at smaller spatial frequencies. Lower values of photoinduced changes in the refractive index of nanocomposites were ob‐ served at high spatial frequencies. This evidence predicts the strong correlations between

Carbon Nanotubes Influence on Spectral, Photoconductive, Photorefractive and Dynamic Properties of the Optical

To support the evidence on correlation between photorefractive and photoconductive fea‐ tures of the materials studied, the volt-current characteristics for nanoobjects-doped solid thin films and pure ones has been measured. After that charge carrier mobility has been esti‐ mated using the Child–Langmuir current–voltage relationship [20] following the formula (5)

For example, one can calculate the absolute values of the charge carrier mobility in pure and fullerene-modified PI samples. The results of these calculations show that the introduction of fullerenes leads to a tenfold increase in the mobility. The absolute values were estimated for a bias voltage of 10 V, a film thickness of *d* = 2 µm, a dielectric constant of ε ~ 3.3, a fuller‐ ene content of about 0.2 wt % C70, and an upper electrode contact area with a diameter of 2 mm. Under these conditions, the carrier mobility in a fullerene-modified polyimide PI film

/(V s), while the analogous value for pure PI is ~0.17 × 10–5 cm2

values well agree with the data reported in [21], where it was demonstrated that the carrier

(5) used for the estimation of charge carrier mobility is valid in the case of currents limited by the space charge. This situation is characteristic of most of the conjugated organic struc‐ tures (in particular, PIs) in which the charge transfer processes are additionally determined by traps, although formula (5) contains no terms dependent on the illumination intensity. However, taking into account the aforementioned equality of the activation energies of con‐ ductivity and mobility in PIs, the results of calculations of the relative changes in the carrier mobility probably adequately reflect the general trends in mobility variations. This behavior does not contradict the pattern of changes in the mobility observed for the other conjugated

We have also calculated the relative values of the charge carrier mobility µ and estimated that two orders of magnitude differences of charge carrier mobility for the pure and nanoob‐

*V* <sup>−</sup><sup>1</sup> (5)

/(V s). These

Materials

405

http://dx.doi.org/10.5772/50843

/(V s). Relationship

µ = 1013*I d* <sup>3</sup> × *ε* <sup>−</sup><sup>1</sup>

mobility in pure PI films ranges in the interval from 10–7 to 0.5 × 10–5 cm2

organic systems, for example, for the fullerene–carbazole one [22].

photorefractive and photoconductive parameters.

shown below:

is ~0.3 × 10–4 cm2

where α(n) – dipole polarizability and υ – local volume.

Therefore, using the fact that polarizability of all structures can be accumulated from local volumes, it can be found that increased micropolarization of system (see eq.4) will predict the dynamic properties improvement and high electro-optical response speed.

$$P \stackrel{\circ}{\simeq} = \stackrel{\circ}{\chi} \chi^{\langle 1 \rangle} E^{\circ} + \stackrel{\circ}{\chi} \chi^{\langle 2 \rangle} E^{\circ 2} + \stackrel{\circ}{\chi} \chi^{\langle 3 \rangle} E^{\circ 3} + \dots + \stackrel{\circ}{\chi} \chi^{\langle \text{nb} \rangle} E^{\circ \text{n}^{\circ}} + \dots \tag{4}$$

It should be mentioned (see Table 1) that the larger nonlinear optical parameters have been found for CNTs-doped organic systems or CNTs-nanofibers-doped ones. It is natural to sug‐ gest (see Fig.8) that variations of the length, of the surface energy, of the angle of nanoobject orientation relative to the intramolecular donor can significantly change the pathway of charge carrier transfer, which will lead to changes in the electric field gradient, dipole mo‐ ment (proportional to the product of charge and distance), and mobility of charge carriers.

**Figure 8.** Schematic diagram of possible charge transfer pathways depending on the arrangement of introduced in‐ termolecular acceptor relative to the intramolecular donor

In addition, the barrier free charge transfer will be influenced by competition between the diffusion and drift of carriers during the creation of diffraction patterns with various peri‐ ods and, hence, differing charge localization at the grating nodes and antinodes. Indeed, in the case of a nanocomposite irradiated at small spatial frequencies (large periods of record‐ ed grating), a drift mechanism of the carrier spreading in the electric field of an intense radi‐ ation field will moist probably predominate, while at large spatial frequencies (short periods of recorded grating) the dominating process is diffusion. This also naturally accounts for the aforementioned discrepancy of published data on photoinduced changes in the refractive in‐ dex of nanocomposites, greater values of which were observed (see, e.g., data presented in the table for systems doped with CNTs and MIG nanofibers) at smaller spatial frequencies. Lower values of photoinduced changes in the refractive index of nanocomposites were ob‐ served at high spatial frequencies. This evidence predicts the strong correlations between photorefractive and photoconductive parameters.

*χ* (n) =*α* (n)

the dynamic properties improvement and high electro-optical response speed.

*Е* <sup>2</sup> ° + *χ* (3)

Therefore, using the fact that polarizability of all structures can be accumulated from local volumes, it can be found that increased micropolarization of system (see eq.4) will predict

It should be mentioned (see Table 1) that the larger nonlinear optical parameters have been found for CNTs-doped organic systems or CNTs-nanofibers-doped ones. It is natural to sug‐ gest (see Fig.8) that variations of the length, of the surface energy, of the angle of nanoobject orientation relative to the intramolecular donor can significantly change the pathway of charge carrier transfer, which will lead to changes in the electric field gradient, dipole mo‐ ment (proportional to the product of charge and distance), and mobility of charge carriers.

**Figure 8.** Schematic diagram of possible charge transfer pathways depending on the arrangement of introduced in‐

termolecular acceptor relative to the intramolecular donor

*Е* <sup>3</sup> ° +…+ °*χ* (n)

where α(n) – dipole polarizability and υ – local volume.

404 Syntheses and Applications of Carbon Nanotubes and Their Composites

*Е* ° + °*χ* (2)

*Р* °= °*χ* (1)

/ *υ* (3)

*Е* n° + ... (4)

To support the evidence on correlation between photorefractive and photoconductive fea‐ tures of the materials studied, the volt-current characteristics for nanoobjects-doped solid thin films and pure ones has been measured. After that charge carrier mobility has been esti‐ mated using the Child–Langmuir current–voltage relationship [20] following the formula (5) shown below:

$$
\mu = 10^{13}Id^3 \times \varepsilon^{-1} V^{-1} \tag{5}
$$

For example, one can calculate the absolute values of the charge carrier mobility in pure and fullerene-modified PI samples. The results of these calculations show that the introduction of fullerenes leads to a tenfold increase in the mobility. The absolute values were estimated for a bias voltage of 10 V, a film thickness of *d* = 2 µm, a dielectric constant of ε ~ 3.3, a fuller‐ ene content of about 0.2 wt % C70, and an upper electrode contact area with a diameter of 2 mm. Under these conditions, the carrier mobility in a fullerene-modified polyimide PI film is ~0.3 × 10–4 cm2 /(V s), while the analogous value for pure PI is ~0.17 × 10–5 cm2 /(V s). These values well agree with the data reported in [21], where it was demonstrated that the carrier mobility in pure PI films ranges in the interval from 10–7 to 0.5 × 10–5 cm2 /(V s). Relationship (5) used for the estimation of charge carrier mobility is valid in the case of currents limited by the space charge. This situation is characteristic of most of the conjugated organic struc‐ tures (in particular, PIs) in which the charge transfer processes are additionally determined by traps, although formula (5) contains no terms dependent on the illumination intensity. However, taking into account the aforementioned equality of the activation energies of con‐ ductivity and mobility in PIs, the results of calculations of the relative changes in the carrier mobility probably adequately reflect the general trends in mobility variations. This behavior does not contradict the pattern of changes in the mobility observed for the other conjugated organic systems, for example, for the fullerene–carbazole one [22].

We have also calculated the relative values of the charge carrier mobility µ and estimated that two orders of magnitude differences of charge carrier mobility for the pure and nanoob‐ jects-doped films has been found. Moreover, the following relation for the charge carrier mobility has been proposed:

$$
\mu\_{\text{pure organic systems}} < \cdot \mu\_{\text{C70,C60}} < \cdot \mu\_{\text{CNT,QD}} \tag{6}
$$

PI+quantum dots based on CdSe(ZnS)

PI + doublewalled carbon nanotube powder

PI + doublewalled carbon nanotube powder

PI+ mixture of CNT and nanofibers (type MIG)

PI+ mixture of CNT and nanofibers (type MIG)

Polymerdispersed LC based on PI– C70 complex

> COANP+ TCNQ\*\*

Polymerdispersed LC 0.003 532 0.2-0.3 100 10 2.0x10-3 [10]

Materials

407

http://dx.doi.org/10.5772/50843

Carbon Nanotubes Influence on Spectral, Photoconductive, Photorefractive and Dynamic Properties of the Optical

0.1 532 0.1 100 10 9.4x10-3 [15]

0.1 532 0.1 150 10 7.0x10-3 [15]

0.1 532 0.3-0.6 90-100 10 11.7x10-3 [15]

0.1 532 0.3-0.6 150 10 11.2x10-3 [15]

0.2 532 0.1 90-100 10 1.2x 10-3 [10]

0.1 676 2.2 Wсm-2 2x10-5 [16]

0.5 532 30×10−3 100 10 1.2×10-3 present

COANP 0 532 0.9 90-100 10-20 10-5 [14]

COANP+C60 5 532 0.9 90-100 10-20 6.21x10-3 [14] COANP+C70 0.5 532 0.6 100 10 5.1x10-3 present COANP+C70 5 532 0.9 90-100 10-20 6.89x10-3 [14]

PI+CNTs 0.1 532 0.5-0.8 90-100 10-20 5.7x10-3 [6] PI+ CNTs 0.05 532 0.3 150 20 4.5x10-3 [6,14] PI+ CNTs 0.07 532 0.3 150 20 5.0x10-3 [6,14] PI+ CNTs 0.1 532 0.3 150 20 5.5x10-3 [6,14]

The observation of the increase of charge carrier mobility, high refractive index and high value of cubic nonlinearities predicts that the nonlinear optical and the dynamic feature of the nanostructured conjugated materials can be optimized via nanostructurization with good advantage. It should be noted that classical inorganic nonlinear volume media (includ‐ ing BSO, LiNbO3, etc.) exhibit significantly lower nonlinearity, while bulk silicon based ma‐ terials have nonlinear characteristics analogous to those of the organic thin film nanoobjectsdoped materials under consideration.


Carbon Nanotubes Influence on Spectral, Photoconductive, Photorefractive and Dynamic Properties of the Optical Materials http://dx.doi.org/10.5772/50843 407

jects-doped films has been found. Moreover, the following relation for the charge carrier

The observation of the increase of charge carrier mobility, high refractive index and high value of cubic nonlinearities predicts that the nonlinear optical and the dynamic feature of the nanostructured conjugated materials can be optimized via nanostructurization with good advantage. It should be noted that classical inorganic nonlinear volume media (includ‐ ing BSO, LiNbO3, etc.) exhibit significantly lower nonlinearity, while bulk silicon based ma‐ terials have nonlinear characteristics analogous to those of the organic thin film nanoobjects-

> **Energy density, Jсm-2**

NPP 0 532 0.3 100 20 0.65x10-3 [14] NPP+C60 1 532 0.3 100 20 1.65x10-3 [14] NPP+C70 1 532 0.3 100 20 1.2x10-3 [14]

PNP+C60 1 532 0.3 100 20 0.8x10-3 [14] PI 0 532 0.6 90-100 10-20 10-4-10-5 [5]

PI+shungites 0.1 532 0.6 150 10 3.1x10-3 present PI+shungites 0.2 532 0.063-0.1 150 10 5.3x10-3 [9,15] PI+С<sup>60</sup> 0.2 532 0.5-0.6 90-100 10-20 4.2x10-3 [5] PI+С<sup>70</sup> 0.2 532 0.6 90-100 10-20 4.68x10-3 [5] PI+С<sup>70</sup> 0.5 532 0.6 90-100 10-20 4.87x10-3 [5] PI+С<sup>70</sup> 0.1-0.5 1315 0.2–0.8 100 50 ~10-3 [14]

0.2 532 0.5-0.6 90-100 10-20 2.87x10-4 [5]

0.1 532 0.2 100 10 3.4x10-3 present

0.2 532 0.28-0.3 100 10 3.65x10-3 present

PNP\* 0 532 0.3 100 20 \*

**Spatial frequency, mm-1**

**Laser pulse duratio n, ns**

**Laserinduced change in the refractive index, (n**

**References**

*μ*pure organic systems< ⋅*μ*C70,C60 < ⋅*μ*CNT,QD (6)

mobility has been proposed:

doped materials under consideration.

**Structure Content of**

PI+malachite green dye

PI+graphene oxides

PI+graphene oxides

**dopants, wt.%**

406 Syntheses and Applications of Carbon Nanotubes and Their Composites

**Wavelength , nm**



**•** Special role of the dipole moment as a macroscopic parameter of a medium accounts for a relationship between the photorefraction and the photoconductivity characteristics.

Carbon Nanotubes Influence on Spectral, Photoconductive, Photorefractive and Dynamic Properties of the Optical

Materials

409

http://dx.doi.org/10.5772/50843

**•** The photorefractive parameters change can be considered as the indicator of following

As the result of this discussion and investigation, new area of applications of the nanostruc‐ tured materials can be found in the optoelectronics and laser optics, medicine, biology, tele‐ communications, display, microscopy technique, etc. Moreover, the nanostructured materials can be used for example, for development of 3D media with high density of re‐ cording information, as sensor in the gas storage and impurity testing, as photosensitive lay‐

The author would like to thank their Russian colleagues: Prof. N. M. Shmidt (Ioffe Physical-Technical Institute, St.-Petersburg, Russia), Prof. E.F.Sheka (University of Peoples' Friend‐ ship, Moscow, Russia), Dr.N.N.Rozhkova (Institute of Geology, Karelian Research Centre, RAS), Dr.A.I.Plekhanov (Institute of Automation and Electrometry SB RAS, Novosibirsk, Russia), Dr.V.I.Studeonov and Dr.P.Ya.Vasilyev (Vavilov State Optical Institute, St.-Peters‐ burg, Russia), as well as foreign colleagues: Prof. Francois Kajzar (Université d'Angers, An‐ gers, France), Prof. D.P. Uskokovic (Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, Belgrade, Serbia), Prof. I.Kityk (Politechnica Czestochowska, Czesto‐ chowa, Poland), Dr. R.Ferritto (Nanoinnova Technologies SL, Madrid, Spain) for their help in discussion and study at different their steps. The presented results are correlated with the work supported by Russian Foundation for Basic Researches (grant 10-03-00916, 2010-2012).

dynamic and photoconductive characteristics change.

**Acknowledgements**

**Author details**

**References**

Natalia V. Kamanina1\*

Address all correspondence to: nvkamanina@mail.ru

1 Vavilov State Optical Institute, 12, Birzhevaya Line, St. Petersburg, , Russia

C60 in toluene solution. *J. Phys. B: At. Mol. Opt. Phys.*, 8, 4537-4554.

[1] Couris, S., Koudoumas, E., Ruth, A. A., & Leach, S. (1995). Concentration and wave‐ length dependence of the effective third-order susceptibility and optical limiting of

er in the spatial light modulators, convertors, limiters, etc. devices.

**Table 1.** Laser-induced change in the refractive index in some organic structures doped with nanoobjects. \* The diffraction efficiency has not detected for these systems at this energy density. \*\* Dye TCNQ - 7,7,8,8, tetracyanoquinodimethane – has been used in the paper [16].
