Form 1

2018 Report Form for Collaboration with
Research Center for Biomedical Engineering

Year/month/date
NumberDate /Month/Year
date: 2019/03/12

To Chairman, Board of Directors, Research Center for Biomedical Engineering

Affiliation
Title

ApplicantMoldova State University
Dr. Assoc. Profesor

Name
Address

Tamara Potlog
Chisinau, MD 2009 Moldova

Phone
Fax
E-mail373 69953854
373 22 244248
tpotlog@gmail.com
Report Form for Collaboration Research

Research Theme

Research Area

Research Period

Development of metal-phthalocyanine-perylene diimide derivates composite
materials for photodynamic therapy and photon harvesting in bulk
heterojunction photovoltaic devices
1. Biomaterials
2. Bioengineering
3. Functional molecules
4. Chemistry/Electrical Engineering/Mechanical Engineering/Materials Science

From:

Date/month/Year
19/10/2018

To: Date/month/Year
23/12/2019

Applicant Organization
Name
Tamara Potlog

Department
Department of Physics and Engineering

Collaboration Partners
Research Center

in

Title
Assoc. Prof.

theProfessor Hidenori Mimura RIE, Shizuoka University

Role
Experiments
and analysis

Research Results (Including Purpose, Results, Figures, etc.)
Synthesis of multifunctional zinc oxide (ZnO) thin films
1. Purpose of Research
Wide band gap ZnO II-VI compound semiconductor can be used in the development of several optoelectronic device
applications, such as ultraviolet (UV) light emitters, spin functional devices, gas sensors, transparent electronics, andsurface acoustic wave devices. ZnO crystallizes in a cubic zinc blende and/or hexagonal wurtzite structure with lattice
parameters a = 3.2495 Å and c = 5.2069 Å, and the density 5.605 g/cm3. ZnO films with cubic structure growperpendicular to the (111) plane, while the hexagonal structure is textured in the [002] orientation. In addition to theintrinsic dopants, ZnO can be doped with Al, Ga and In to obtain an enhanced n-type conductivity and/or with N, Mn
and Li to obtain the p-type conductivity. Therefore, studies focused on:1) preparation of ZnO thin films doped with Al and Ga from chemical solution by spray pyrolysis method in neutral
and oxidizing atmosphere; 2) annealing in vacuum; 3) investigation and analysis of the physico-chemical processes
responsible for the change of the doped ZnO thin film properties as a result of the effect of carrier gas atmosphere andannealing.
2. Results
For the synthesis of ZnO thin films, zinc acetate (Zn (CH3COO)2·2(H2O)) with a concentration of 0.2 M dissolved inacetic acid-methanol-water solution in the ratio 10:25:65 was used. As the dopant source, aluminum nitrate was used.
The concentration of Al was varied between 1% and 5% in the initial solution. Al-doped ZnO thin films were depositedon glass substrates by spray pyrolysis technique. Details of the deposition system and method are described in paper.
The equipment allows the deposition of ZnO layers on the area up to 80 cm2. The furnace temperature is kept constantat an accuracy of ± 5°C. The oxygen and argon gases were used as the carrier gas. Spray rate of the solution was 30
ml/min. The temperature of the substrate and the carrier gas pressure were 450◦C and 2 bar, respectively. The distance
between the substrate and solution source was 30 cm. Glass substrates were, preventively, cleaned in toluene, isopropyl
alcohol, corroded in + 5% Br methanol solution for 10 min and then dried in isopropyl alcohol vapors. First set of
Al-doped ZnO films was synthetized in O2 atmosphere and then vacuum annealed at 430°C for one hour in thedeposition chamber, under a pressure of 4.0 ∙10 −5 mbar. A second set of Al-doped thin films was synthetized in Ar
atmosphere and then annealed in the same
condition like the first set.
TABLE 1. Structural parameters of as deposited Al-ZnO thin films obtainedin O2 atmosphereO2 atm.

Nr.

2θ

d (ang)

(deg)

FWHM

D

ɛ

(rad)

(ang)

(latticestrain)x10-3As-dep.

undoped34.46

2.60150.0057281.994.61

Al- ZnO1%

34.48

2.60040.0053301.60

4.31

thin

2%

34.48

2.60030.0052

312.23

4.16

films

3%

34.49

2.59980.0056289.07

4.5

5%

34.48

2.60030,0056286.88

4.53

TABLE 1. Structural parameters of as deposited Al-ZnO thin films
Figure 1. The XRD patterns of the as deposited undoped
and
Al-doped ZnO thin films in O2 atmosphereobtained in O2 atmosphere
The diffraction patterns for the first set of the as-deposited undoped and Al-doped ZnO thin films synthetized in O2
atmosphere are shown in Fig. 1. As can be seen in Fig. 1, the films’ peak intensities of (100), (101) and other planesof diffraction are very small in comparison with the intensity of (002) plane. The all films exhibited a preferred (002)orientation. Fig. 1. The XRD patterns of the as deposited undoped and Al-doped ZnO thin films in O2 atmosphere

Therefore, the interplanar distance (d) value of the all ZnO films indicated in the table 1 is presented only for themost intensive position peak situated at about 2θ = 34.5° that corresponds to the (002) crystallographic diffraction
plane. The intensity of this peak slightly decreases with increasing the Al concentration up to 3 %. At thisconcentration it`s observed the highest intensity of the 2θ = 34.5° peak. This suggests good crystalline quality of Al3% ZnO film in comparison with the undoped sample. However, the (002) peak intensity decreases with further
increase of Al content up to 5% in the film. The diffractograms of the second set of the as-deposited undoped andAl-doped ZnO thin films synthetized in Ar atmosphere are shown in Fig. 2. The diffractograms show another type of
behavior for the most intensive peak situated at 2θ = 34.5°. The intensity of (100), (101) and (002) planes for the asdeposited undoped thin film are about the same. The most intensive peak is depicted for the 1% Al-doped ZnO film.
The average strain and crystal grain sizes of (002) crystal plane for this set of ZnO thin films are presented in Table
2. The value of grains size of the as-deposited Al-ZnO thin films in Ar atmosphere reveal that the crystalline quality
with Al doping is weakened less in comparison with of that synthetized in oxygen atmosphere (See tables 1 and 2 forcomparison). For the sample obtained in Ar atmosphere with Al-doping concentration of 1 at%, grains tend toincrease in size because of the lower strain of the crystal lattice in the film in comparison with the undoped ZnO thinfilm. However, when Al-doping concentration is 2 at%, and 3 at%, grains size decrease because of greater strain of
the crystal lattice.
TABLE 2 structural parameters of as-deposited Al-ZnO thin films

in Ar atmosphere
Ar atm.

Nr.

2θ

d (ang)

(deg)

FWHM

D

ɛ

(rad)

(ang)

(latticestrain)x10-3As-dep.

undope

Al-

d

34.49

2.59960.0055292.56

4.44

ZnO

1%

34.48

2.60020.0055294.46

4.42

thin

2%

34.49

2.59990,0057284.27

4.57

films

3%

34.50

2.59900,0055291.08

4.44

5%

34.47

2.60110.0053305.58

4.26

Figure 2. The XRD patterns of the asdeposited undoped andAl-doped ZnO thinfilms in O2 atmosphere
In the case of higher doping 5 at%, the grains size increase due to lower strain, leading to better crystallinity. Other isthe situation with the Al-doped ZnO thin films obtained in the O2 atmosphere. The biggest grain size for 2 at%
Al-doped ZnO film, but the smallest grain size for the higher doped 5 at% Al film are observed. This illustrates that the
crystalline structure is influenced by the nature of gas atmosphere in which the films are synthetized. The slightly
shifting of the position of the peaks in comparison with tabular data indicates the presence in them of various kinds ofdefects.
The effect of thermal annealing in the vacuum onthe structural properties of Al-doped ZnO thin films is investigated.
Figures 3 and 4 show the XRD spectra of the thermal annealed undoped ZnO and Al-doped thin films in O2 and Ar
a35tZnO_Al5%_Ar_vac._anneal
atmospheres.
a34tZnO_Al3%_Ar_vac._anneal

Intensity, arb.un.

a33tZnO_Al2%_Ar_vac._anneal
a36tZnO_Al1%_Ar_vac._anneal
a21tZnO_Al5%_vac._anneal

30

40

50

60

70

80

2, degree

Figure 3. The XRD patterns of the vacuum annealed
undoped and Al-doped ZnO thin films in O2 atmosphere

Figure 4. The XRD patterns of the vacuum annealedand Al-doped ZnO thin films in Ar atmosphereAfter annealing at 450◦C, the broad band covering the whole spectrum in all samples obtained in O2 atmospheredisappears, but in the samples obtained in Ar are kept. This indicate an overall improvement of the crystal quality of the
Al-doped synthetized in O2 atmosphere. The XRD patterns for the thermal annealed 1 at% Al- and 2 at% Al-doped
ZnO thin films synthetized in O2 atmosphere reveal a very lowest intensity peak situated at 2θ = 32.95° that corresponds
to Al2O3 phase, oxidized from the Al in the ZnO films. For the undoped ZnO film obtained in Ar atmosphere the latticestrain increases after annealing, but for those obtained in O2 decreases. The value of grains size for all Al
concentrations in ZnO films obtained in Ar atmosphere after annealing decreases with the increases of the Alconcentration. Generally, the Al-doped ZnO obtained by spray pyrolysis in the present paper show growth of the films
oriented along the (002) plane as in the most publications. The crystalline quality of the Al-doped ZnO films enhances
after thermal annealing irrespective of the Al doping and it is in good agreement with results obtained by researchteams.
The gallium chloride (GaCl) was used for the doping of ZnO. Also, two sets of Ga-doped ZnO thin films were preparedin the same conditions. XRD patterns for obtained ZnO thin films in argon (Ar) and oxidizing atmosphere (O 2) before
and after vacuum annealing at 450oC illustrated in Fig.1 show no evidence of secondary phases, except a crystalline
ZnO phase. The revealed main high intensity (002) peak in all films, with exception of as-deposited and undoped ZnO
thin films located at approximately 34.45 o has been assigned in the literature as corresponding to hexagonal
modifications textured in the [002] direction. From this it follows that these films are polycrystalline with hexagonal
structure and the predominant orientation of the c axis perpendicular to the plane of the substrate. This result is in good
agreement with the literature data. A shifting of the (002) peak is observed for the ZnO thin films doped with 2% Ga
and annealed at 450oC in vacuum from 2θ = 34.45° to 34.50° for all doped samples. For the obtained film in theoxidizing atmosphere and non-annealed, the more intensive peak is located close to 36.25o with ZnO phase textured inthe [101] orientation. thermal annealing of the samples leads to a decrease in the size of the crystallites (see more
intensive (002) plane) in the case of the O2 gas atmosphere, while in the case of the Ar gas leads to an increase in thegrain size. It can, also, be argued that annealing and nature of the gas atmosphere did not change the nature of the
texture but resulted in the appearance of additional low intensity reflections of the hexagonal lattice in some samples.
The (110) plane has a very small intensity. The undoped ZnO and ZnO:Ga thin films had compressive strains becauseof different values of thermal coefficient of glass and material or may be due to a slight increase in relative strain
originating from the substitution of Zn2+ ions with relatively smaller Ga3+ ions. Doping was observed to haveinsignificant effects on the strain as evidenced by almost similar (002) peak positions and about equal interplanar
distances for all films at this peak position. The intensity of the diffraction peaks decreases after doping and annealing
at 723 K and their width at half-height slightly changes. The shifting of the position of the peaks in comparison withtabular data [16] indicates the presence in them of various kinds of defects. On the other hand, the annealing of ZnO
thin films in vacuum at 723 K decrease the interplanar distance for both types of gas atmospheres in comparison with
ZnO pure. This shows that Ga managed to substitute Zn and can reasonably reside on zinc site in the hexagonal lattice.
This may be due to the fact that Ga3+ ions replace the Zn2+ ions in the ZnO lattice in the case of doping with 2 at% Ga.

(103)

(002)
(002)
(101)
(101)

(103)
(103)

(110)

(100)

(110)

(102)

2

5,0x10

(103)

(102)

(101)

(100)
(100)

3

1,0x10

(002)

(100)

3

1,5x10

(002)
(101)

Intensity, arb.un.

32,0x10

(002)
(101)

3

2,5x10ZnO_L090917_ZnO_pure
ZnO_L120917_Ga_ Ar_treated vacuum
ZnO_L121217_Ga_Ar_untreated
ZnO_L080917_Ga_O2_treated_vacuum
ZnO_L070917_Ga_O2_untreated

0,0

25

30

35

40

45

50

55

60

65

70

2, degree

Figure 5 XRD patterns of pure ZnO thin films and prepared
2%Al-doped in argon (Ar) and oxidizing atmosphere (O2)
before andafter vacuum annealing at 450oC

Figure 6 AFM image of as-deposited
ZnO synthetized in Ar atmosphere.

For the comparison, Fig.6 shows the surface topography (as shown by the AFM imagistic) of the as-deposited 2
at% Al ZnO film synthetized in Ar atmosphere, while Fig.7 and Fig.8 show the AFM images of vacuum annealed at
450 °C for 1 hour of 2 at% Al doped ZnO thin films synthetized in Ar and O2 atmospheres.

Figure 7 AFM image of vacuum annealed

Figure 8 AFM image of vacuum annealed

2%Al-doped ZnO synthetized in Ar atmosphere.

2%Al-doped ZnO synthetized in O2 atmosphere.

The transmission and reflectance spectra for the first set of the as-deposited undoped and Al-doped ZnO thin films
synthetized in O2 are presented in Figure 8. For the undoped ZnO thin film the highest transmittance is observed.
Doping with Al slightly decrease the optical transmittance of the as deposited films, and the transmittance in the visible
region is still higher than 80% which is important for the applications in the field of photovoltaics. The film thickness isestimated from cross-sectional view of SEM and is 292 nm for undoped and 305 nm for Al-doped ZnO films. The
estimated Eg values of both, undoped and doped with different concentration of Al ZnO films in O 2 atmosphere show aslight decrease of the band gap, within the experimental errors (0.02 eV). From the Figure 9 can be observed that thetransmittance of the all thermal annealed Al-doped ZnO layers obtained in the O 2 atmosphere varies between 70% 90%, the maximum of 90% being reached at longer wavelength for the 5 at% Al-doped ZnO layer. The lowest
transmittance shows the 2 at% Al-doped ZnO thin film.

80

80

40
20
0
300

400

500

600

l, nm

700

T, %

60

T_a32_ZnO_O2_atm_as_dep
T_a28_ZnO_O2_atm_1%Al
T_a29_ZnO_O2_atm_2%Al
T_a30_ZnO_O2_atm_3%Al
T_a31_ZnO_O2_atm_5%Al
R_a28_ZnO_O2_atm_1%Al
R_a30_ZnO_O2_atm_3%Al
R_a31_ZnO_O2_atm_5%Al

40

20

20

0

0
300

Figure 9 The transmission and reflectance spectra
for the as deposited undoped and Al-doped ZnO thinfilms synthetized in O2 atmosphere80
T_a30t_ZnO_O2_Al3%_vac_anneal
T_a31t_ZnO_O2_Al5%_vac_anneal

60

40

800

100

80

R,%

60

100

T_a32t_ZnO_O2_undoped_vac_anneal
T_a28t_ZnO_O2_Al1%_vac_anneal
T_a29t_ZnO_O2_Al2%_vac_anneal

60
40

R_a32t_ZnO_O2_undoped_vac_anneal
R_a28t_ZnO_O2_Al1%_vac_anneal
R_a29t_ZnO_O2_Al2%_vac_anneal
R_a30t_ZnO_O2_Al3%_vac_anneal
R_a31t_ZnO_O2_Al5%_vac_anneal

400

500

600

l, nm

700

R, %

100

T,%

100

20

0
800

Figure 10 The transmission and reflectance spectra forthe thermal annealed undoped andAl-doped ZnO thinfilms in O2 atmosphereWith the increasing concentration of Al, the value of band gap (Eg) slightly varied and displays a growing trend with theincreasing concentration of Al from 3.25 eV for undoped and to 3.32 eV for 5 at% Al-doped ZnO thin films. The
estimated values of the band gap agree well with the data literature values for Al-doped ZnO thin films. Also, all spectraof as deposited and thermal annealed ZnO thin films show a decrease of transmission near the fundamental absorption,
which identifies a good crystallinity of the obtained layers. Figure 10 illustrates the transmission and reflectance spectra
for the second set of the as-deposited undoped and Al-doped ZnO thin films synthetized in Ar atmosphere.

80

80

80

80

T_a21_ZnO_as_dep_Ar_atm.
T_a36_ZnO_Al1%_Ar_atm.
T_a33_ZnO_Al2%_Ar_atm.
T_a34_ZnO_Al3%_Ar_atm.
T_a35_ZnO_Al5%_Ar_atm.
R_a21_ZnO_as_dep_Ar_atm.
R_a36_ZnO_Al1%_Ar_atm.
R_a33_ZnO_Al2%_Ar_atm.
R_a34_ZnO_Al3%_Ar_atm.
R_a35_ZnO_Al5%_Ar_atm.

60
40
20
0
300

400

500

600

l, nm

700

60
40
20

0
800

60

T_a21t_ZnO_Ar_vac anneal
T_a36t_1%al_ZnO_Ar_vac_anneal
T_a33t_2%al_ZnO_Ar_vac_anneal
T_a34t_3%al_ZnO_Ar_vac_anneal
T_a34t_5%al_ZnO_Ar_vac_anneal
R_a36t_1%al_ZnO_Ar_vac_anneal
R_a33t_2%al_ZnO_Ar_vac_anneal
R_a34t_3%al_ZnO_Ar_vac_anneal
R_a35t_5%al_ZnO_Ar_vac_anneal

40
20
0
300

60
40

R, %

100

T, %

100

R, %

100

T, %

100

20
0

400

500

600

700

800

l, nm

Figure 11 The transmission and reflectance spectra for

Figure 12 The transmission and reflectance spectra forthe as deposited undoped andthe thermal annealed undoped andAl-doped ZnO thin

Al-doped ZnO thinfilms in Ar atmospherefilms in Ar atmosphere

The transmittance of as deposited undoped and Al-doped ZnO thin films in Ar atmosphere in the visible region isslightly higher in comparison with of as deposited undoped andAl-doped ZnO thin films in O2 atmosphere. The
value of Eg for all ZnO thin films synthetized in Ar atmosphere reaches the same values as in the case of the set of ZnO
thin films synthetized in O2 atmosphere. The transmittance and reflectance of thermal annealed undoped andAl-doped ZnO thin films in Ar atmosphere are presented in Figure 12. The thermal annealed undoped ZnO thin films
show the lowest transmittance. The transmittance of the all thermal annealed Al-doped ZnO thin films in the visible
region are higher than 85% and it is modified in the limit of 10%. The Eg for the undoped film is 3.26 ev, while for the
Al-doped ZnO thin films reaches the value of 3.29 eV and it vary in the limit within the experimental errors (0.03 eV).
The value of the reflectivity over measured wavelengths for both sets of ZnO thin films vary from about 80% to about
85%. For photovoltaic application of transparent conducting oxide thin films, not only high transparency over thevisible light region is essential, but also high conductivity is required. The resistivity of as deposited Al-doped ZnO thinfilms, for both sets synthetized in O2 and Ar atmospheres, measured at room temperature is highly and does not presentinterest for photovoltaic applications.

d, W-1cm-1

40

Ar
O2

30
20

Figure 13 The conductivity vs. Al content of ZnO thinfilms synthetized in Ar atmosphere

10
0
1

2

3

4

5

Al content, (at%)

The ZnO films conductivity vs. Al content show that by increasing the Al concentration the conductivity decreases indifferently trends, in function of the synthetized gaseous atmosphere. Probably, the conductivity is reduced withincreasing of the Al concentration due to distortion of the ZnO lattice and formation of the defects or neutral complexes[26, 27]. The Al-doped ZnO thin films in the O2 atmosphere showed increased resistivity in comparison with thoseobtained in Ar gas ambient. The 1.0 at % Al –doped ZnO thin film synthetized in Ar atmosphere exhibit the highest
value of conductivity. The origin of the increasing conductivity is the generation of free charge carriers which are
influenced by the oxygen vacancies and Zn interstitials, that in our case is influenced by the nature of gaseousatmospheres. Both structural defects provide extra electrons as free charge carriers.
Finally, have been investigated structure, optical and electrical properties of Al-doped ZnO thin films synthetized byspray pyrolysis in Ar and O2 atmospheres. The XRD analysis shows, that indifferently of the nature of gas atmosphereused in the preparation, the undoped and Al-doped ZnO films are polycrystalline and show the [002] preferredcrystallite orientation. Also, it is observed that higher structural distortion can be related to lower crystallite size. After
thermal annealing both sets of Al-doped ZnO films exhibit a better crystallization, however the XRD patterns of thethermal annealed 1 at% - and 2 at% Al-doped ZnO thin films synthetized in O2 atmosphere reveal the formation of
Al2O3 phase. For all Al-doped ZnO thin films deposited in both atmospheres an increase of film roughness after vacuum
annealing is noted. The transmittance of the as deposited and thermal annealed first set of ZnO thin films deposited in
Ar atmosphere in the visible region is slightly higher in comparison with of second set synthetized in O2 atmosphere,
but still higher than 75% which is important for the applications in the field of photovoltaics. The band gap values of
ZnO films synthetized in Ar atmosphere show a slight decrease of the band gap values (within the experimental errors(0.02-0.03 eV)) compared with that synthetized in O2 atmosphere. The best conductivity is noted for the thermal
vacuum annealed Al-doped ZnO thin films synthetized in Ar atmosphere. The highest conductivity is estimated for 1.0
at % Al –doped ZnO thin films synthetized in Ar atmosphere and vacuum annealed at 450oC.
Physico-chemical properties of self-assembled in solution of zinc phthalocyanine and perylene bismide
This research project gave possibility to develop a new photosensitizer for PDT therapy processed from solution basedon phthalocyanine- perylene diimide derivates higher quantum yield of the singlet oxygen generation and the singlet
oxygen population lifetime.
The more promising photosensitizers that are currently being evaluated for photodynamic therapy (PDT) applications
are the zinc phthalocyanine (ZnPc). ZnPc has strong absorbance at long wavelengths and emission, high extinction
coefficient beyond 630 nm, good singlet oxygen yield, low dark toxicity, but poor solution behavior. Thus ZnPc
requires chemical modification of Pc ring to enhance its bioavailability and photodynamic efficacy. Literature survey
show, that the synthesis of ZnPc complexes and donor-acceptor conjugated complexes based on ZnPc and N, N'-bis(3-pentyl) perylen-3,4,9,10-bis (dicarboximid) (Bis-3-Pentyl-PTCBI) derivative in formic acid (FA) solution, has notbeen reported. Fluorescence and phosphorescence characteristics have reported in different solvents but not studied informic acid solution. The fluorescence spectra were investigated at room temperature ca 22 °C using a Jasco
spectrofluorometer FP-8600 from 200 nm to 800 nm. UV-VIS absorption spectra of the as-deposited ZnPc by close
space sublimation (CSS) and chemical deposited from FA solution by drop casting methods grown on glass substrates
are presented in Fig. 1. The absorbance of ZnPc spectrum obtained by CSS in comparison with of ZnPc solubilized in
FA solution as it can be seen in Fig. 1, exhibit two main bands marked Q and B. The Q band arises due to the excitation
between the ground state a1u (π) HOMO to eg (π*) LUMO and splitting in three distinct peaks. The splitting in Q band islikely due to the vibronic coupling in the excited state. The peaks situated at 1.92 eV and 1.729 eV imply the a 1u to eg
and the 2a21 to 7eg transitions on the phthalocyanine macrocycle, while the 1.656 eV energy peak could have been
attributed to the excitonic transition or vibrational interval. The Soret or B band with two peaks situated at 3.386 eV and
3.727 eV could be attributed to the π–π* transition. The absorbance spectrum for the ZnPc thin films from FA solution
shows within the UV-Visible region of the solar spectrum about the same absorption as in the case of thermal
evaporated and exhibit two broad bands both shifted to longer wavelengths. The highest absorbance is observed within
the Visible-NIR region from 550 nm to 850 nm of the solar spectrum. The broadest Q band exhibits a red shift because
the excited state of the π→π* transition in ZnPc is polar and, thus, stabilized by a polar solvent. Therefore, the transitionenergy decreases and the corresponding band is red shifted. The absorption band can be red shifted due to a chargetransfer. A comparison of absorbance spectra of undoped and doped with iodine ZnPc thin films from chemical FA
solution is presented in the Figure 2. We can observe more representative phthalocyanine absorption B and Q bands inthe spectra. Both these bands arise due to a1u(π- π )to eg(π *) transitions with the dipole moment in the plane of themolecule. The B band is due to a2u( ) to eg(π *) together with b2u(π) to eg(π*) transitions. The Q band is due to a1u(π) toeg(π*) transitions. From figure we can see that the presence of iodine in the ZnPc thin film further increases absorbanceand mitigates more the transmittance region. In addition, the blend of ZnPc and Bis-3-Pentyl-PTCBI solubilized in thesolvent was studied by UV-VIS spectroscopy. Absorbance spectrum of undoped blend of ZnPc with
Bis-3-Pentyl-PTCBI in the weight ratio 2:1 show the same B and Q bands as in the case of the undoped and doped withiodine ZnPc thin films but with further increasing in absorption. The doping of ZnPc: Bis-3-Pentyl-PTCBI blend withiodine increases absorbance and spectrum exhibit three bands with many intensive peaks.

ZnPc from chemical solution
ZnPc doped with iodine from chemical solution
ZnPc thermal evaporated

Absorbance, arb.un.

2,0
1,5

Q band

1,0
0,5
0,0
300

400

500

600

700

ZnPc:Bis-3-Pentyl_PTCBI doped with iodine
ZnPc:Bis-3-Pentyl_PTCBI
Bis-3-Pentyl_PTCBI

82,5

B bandAbsorbance, arb. un

3,0

800

6

4

2

0
300

400

l, nm

500

600

700

800

l, nm

Figure 1. UV-VIS absorption spectra of the as-deposited ZnPc

Figure 2.

by close space sublimation (CSS) and chemical deposited fromundoped and doped with iodine ZnPc and ZnPc:

UV-VIS absorption spectra of the

FA solution by drop casting methods grown on glass substrates

Bis-3-Pentyl-PTCBI thin films

1,0
0,8
0,6
0,4
0,2
0,0
330

335

340

345

l, nm

350

355

360

Em ZnPc doped with iodine
Ex l642 nm

1,0
0,8
0,6
0,4
0,2
0,0
630

635

640

645
l, nm

650

655

Fluorescence Intensity, normalized

Em ZnPc doped with iodine
Ex, 345 nm

Fluorescence intensity, normalized

Fluorescence intensity, normalized

Fluorescence Intensity, normalized

The presence of these well-defined intensive peaks demonstrates the formation of a well-defined supramoleculararchitecture by the self-assembly of ZnPc and Bis-3-Pentyl-PTCBI. The transmittance region of undoped and doped
ZnPc: Bis-3-Pentyl-PTCBI blends spectra became more pronounced in comparison with that of undoped and doped
ZnPc. The broadening and splitting of the Q and B bands indicating the presence of additional electronic levels of theaggregates due to non-covalent, π-π interactions between the conjugated Pc rings.
The measurements of fluorescence and synchronous fluorescence spectra were made using excitation in the wavelength
region 200-850 nm. Fluorescence is observed from all undoped and doped ZnPc and ZnPc:PDI in mixture of FA andDMF solvents. For example, in the Figure 3 are presented fluorescence spectra at different wavelengths for ZnPc thinfilm doped with iodine obtained from chemical solution.
Em ZnPc dpoed with iodine
Ex l535 nm

1,0
0,8
0,6
0,4
0,2
0,0
520

525

530

535
l, nm

540

545

550

Em ZnPc doped with I2
Ex l840 nm

1,0
0,8
0,6
0,4
0,2
0,0
830

835

840

845

850

l, nm

Figure 3. Fluorescence spectra of ZnPc doped with iodine at different excitation wavelengths in solvent mixture fromformic acid and DMF.

3,5

ZnPc from chemical solution, Exsingle, l=840 nm
ZnPc doped with iodine

Exsingle l nm
Emsingle ZnPc(I2):Bis-3-Pentyl-PTCBI from chemical solution

1,6x1033,02,5

1,2x1032,08,0x1021,5
1,04,0x102

0,5
0,0
830

Emsingle Intensity, arb.un.

Emsingle Intensity, arb.un.

Fluorescence emission peaks were observed in both Q and the Soret (B) absorption bands.
Energy transfer between the triplet state of photosensitizers and ground state molecular oxygen leads to the productionof singlet oxygen. There is a necessity of high efficiency of transfer of energy between excited triplet state of ZnPc andground state of oxygen to generate large amounts of singlet oxygen, essential for photodynamic therapy.

835

840

845

850

0,0
830

835

840

845

850

Exsingle wavelength, nm

Exsingle wavelength, nm

Figure 4 Singlet oxygen fluorescence spectra of doped ZnPc and ZnPc: Bis-3-Pentyl-PTCBI thin films
Because the conventional fluorescence technique, relying on recording of single emission or excitation spectra, areoften insufficient, the synchronous fluorescence spectra was measured. The technique is based on simultaneously
scanning of the excitation and emission wavelength with constant difference (Δλ) maintained between them.
Synchronous fluorescence intensities acquired for all samples as a function of excitation wavelength are shown in Fig.
1. In our experiment Δλ=60 nm.
.

Fluorescence Intensity, arb.un

ZnPc(I2):PDI from chemical solution
ZnPc:PDI from chemical solution
ZnPc doped with I2 from chemical solution
ZnPc from chemical solution

200

300

400

500

600

700

Excitation Wavelength, nm

Figure 5 Synchronous fluorescence spectra of undoped and doped ZnPc and ZnPc: Bis-3-Pentyl-PTCBI thin films
Zinc phthalocyanine is less soluble in only DMF. The mixture of DMF with formic acid improve solubility of ZnPc.
The presence of Bis-3-Pentyl-PTCBI and iodine substituents on ZnPc tends to make the ring more fluorescent.

List of Publications Related to the Collaboration Research1. Tamara Potlog, Ion Lungu, Vasile Botnariuc, Leonid Gorceac, Simion Raevschi, Miyake Taku Suchada Worasawat,
Hidenori Mimura. Synthesis and Properties of Al-doped ZnO Thin Films for Photovoltaics. Proceedings ofthe 4th International Conference on Nano Electronics Research Education (ICNERE 2018), Hamamatsu, Japan, 2018,978-1-5386-7553-3/18/$31.00 ©2018 IEEE.
2. T. Potlog, I. Lungu, V. Botnariuc, S. Raevschi, L.Gorceac, S. Worasawat, H.Mimura. Effect of carrier gas and vacuum
annealing on the physical properties of ZnO thin films doped with gallium by chemical spray pyrolysis. The 6thinternational conference on telecommunications, electronics and informatics, May 24-27, p.145-149, 2018.

List of Presentations ( Conference, Meeting, etc)
Tamara Potlog, Ion Lungu, Vasile Botnariuc, Leonid Gorceac, Simion Raevschi, Miyake Taku Suchada Worasawat,
Hidenori Mimura. Synthesis and Properties of Al-doped ZnO Thin Films for Photovoltaics. Proceedings ofthe 4th International Conference on Nano Electronics Research Education (ICNERE 2018), Hamamatsu, Japan, 2018.

List of Awards

Registration of research-theme continuation for next year
Prior consent from the collaboration partner in the Research Center is necessary.

Yes

No

Research plan for the next year (from April 1, 2019 to March 31, 2020), if the collaboration research is continued.
Objectives of the research activities will be:
1 Interface study of the one most suitable ITO/ZnO and ZnO/NiO interfaces fabricated by spray pyrolysis forphotovoltaic applications in solar cells based on ZnPc.
2. XPS depth profiling study of ITO/ZnO and ZnO/ZnPc interfaces.
3. Characterization by current-voltage characteristics at different illumination and measurement temperaturesof the photovoltaic devices with different configurations.