Cathode luminescence properties of organic Lengmuir-Blodgett films
Some investigation results of the b-sensitivity of organic Lengmuir-Blodgett (LB) films irradiated with an electron beam are described. The dependences of the integral luminescence (Δλ=380-450nm) on the electron energy (0.2...6kV) with a constant density (0.05...4.0μA/cm2) are represented. The possi...
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| Дата: | 2001 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2001
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| Назва видання: | Вопросы атомной науки и техники |
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| Цитувати: | Cathode luminescence properties of organic Lengmuir-Blodgett films / N.I. Voronkina, Yu.G. Zaleskiy, A.N. L’vov, V.I. Skibin, E.G. Taller, A.V. Tolmachyov, N.G. Shulika // Вопросы атомной науки и техники. — 2001. — № 3. — С. 173-174. — Бібліогр.: 3 назв. — англ. |
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irk-123456789-792332015-03-31T03:02:10Z Cathode luminescence properties of organic Lengmuir-Blodgett films Voronkina, N.I. Zaleskiy, Yu.G. L’vov, A.N. Skibin, V.I. Taller, E.G. Tolmachyov, A.V. Shulika, N.G. Some investigation results of the b-sensitivity of organic Lengmuir-Blodgett (LB) films irradiated with an electron beam are described. The dependences of the integral luminescence (Δλ=380-450nm) on the electron energy (0.2...6kV) with a constant density (0.05...4.0μA/cm2) are represented. The possible spheres of LB films application as scintillator detectors of ionizing radiation are discussed. 2001 Article Cathode luminescence properties of organic Lengmuir-Blodgett films / N.I. Voronkina, Yu.G. Zaleskiy, A.N. L’vov, V.I. Skibin, E.G. Taller, A.V. Tolmachyov, N.G. Shulika // Вопросы атомной науки и техники. — 2001. — № 3. — С. 173-174. — Бібліогр.: 3 назв. — англ. 1562-6016 PACS numbers: 29.17. +w http://dspace.nbuv.gov.ua/handle/123456789/79233 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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English |
| description |
Some investigation results of the b-sensitivity of organic Lengmuir-Blodgett (LB) films irradiated with an electron beam are described. The dependences of the integral luminescence (Δλ=380-450nm) on the electron energy (0.2...6kV) with a constant density (0.05...4.0μA/cm2) are represented. The possible spheres of LB films application as scintillator detectors of ionizing radiation are discussed. |
| format |
Article |
| author |
Voronkina, N.I. Zaleskiy, Yu.G. L’vov, A.N. Skibin, V.I. Taller, E.G. Tolmachyov, A.V. Shulika, N.G. |
| spellingShingle |
Voronkina, N.I. Zaleskiy, Yu.G. L’vov, A.N. Skibin, V.I. Taller, E.G. Tolmachyov, A.V. Shulika, N.G. Cathode luminescence properties of organic Lengmuir-Blodgett films Вопросы атомной науки и техники |
| author_facet |
Voronkina, N.I. Zaleskiy, Yu.G. L’vov, A.N. Skibin, V.I. Taller, E.G. Tolmachyov, A.V. Shulika, N.G. |
| author_sort |
Voronkina, N.I. |
| title |
Cathode luminescence properties of organic Lengmuir-Blodgett films |
| title_short |
Cathode luminescence properties of organic Lengmuir-Blodgett films |
| title_full |
Cathode luminescence properties of organic Lengmuir-Blodgett films |
| title_fullStr |
Cathode luminescence properties of organic Lengmuir-Blodgett films |
| title_full_unstemmed |
Cathode luminescence properties of organic Lengmuir-Blodgett films |
| title_sort |
cathode luminescence properties of organic lengmuir-blodgett films |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2001 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79233 |
| citation_txt |
Cathode luminescence properties of organic Lengmuir-Blodgett films / N.I. Voronkina, Yu.G. Zaleskiy, A.N. L’vov, V.I. Skibin, E.G. Taller, A.V. Tolmachyov, N.G. Shulika // Вопросы атомной науки и техники. — 2001. — № 3. — С. 173-174. — Бібліогр.: 3 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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| fulltext |
CATHODE LUMINESCENCE PROPERTIES OF ORGANIC
LENGMUIR-BLODGETT FILMS
N.I. Voronkina1, Yu.G. Zaleskiy, A.N. L’vov, V.I. Skibin, E.G. Taller,
A.V. Tolmachyov1, N.G. Shulika
NSC Kharkov Institute of Physics & Technology
1 Institute of Single Monocrystals NAS of Ukraine
Some investigation results of the β-sensitivity of organic Lengmuir-Blodgett (LB) films irradiated with an electron
beam are described. The dependences of the integral luminescence (∆λ=380-450nm) on the electron energy
(0.2...6kV) with a constant density (0.05...4.0µA/cm2) are represented. The possible spheres of LB films application
as scintillator detectors of ionizing radiation are discussed.
PACS numbers: 29.17. +w
1 INTRODUCTION
Now alongside with a traditional radiation sensitive
monocrystal scintillator a good prospect of practical ap-
plication can have thin organic LB films, activated by
organic luminophore. Scintillators, made on base of LB
films, can appear especially effective at the registration
not only of UV radiation but also of low-energy elec-
trons, soft X-rays, heavy particles and low-energy fis-
sion fragments. The increased sensitivity of these films
at registration of a short-range of particle paths and radi-
ation is caused by the dense packing of the luminophore
molecules in monomolecular layers [1]. Depending on
the order of alternation of these monolayers containing
donor-acceptor pairs, it is possible to raise a sensitivity
of the all structure for registration of β-radiation [2].
This report contains description of experiments on exci-
tation of the LB film samples by UV radiation and the
low- energy electron flow.
2 LUMINESCENCE MATERIAL AND
MESUREMENT TECHNIQUES
The experiments were carried out on the film sam-
ple, consisting 1000 monolayers of polymer
tetraphenylbutadiene dope with 10% concentration of
gram-molecules and overall thickness of 1.0 µm. For
formation on a water surface of stable two-component
monolayers and transference them on a glass substrate
with thickness of 1mm and diameter of 13 mm we used
a two-bath installation NIOPIK checked by a computer.
The UV absorption spectra were measured on a spec-
trophotometer SPECORD M-40. The photolumines-
cence was raised by a guartz flashtube DKSSH-150,
from which by a monochromator the light with a wave-
length of 350 and 260 nm has been cut out. The typical
luminescence spectrum of the sample described is given
in Fig. 1.
For measurements of the radioluminescence intensi-
ty from the sample irradiated with an electron flow the
installation was assembled. Its diagram is shown in
Fig. 2. The presence in a design of electrostatic deflect-
ing plates allows not only to decrease a light noise from
the filament of the electron gun but also to direct onto
the target an electron beam with a small disorder in
speeds. A tungsten wire filament provided the current
density up to 4.0µA/cm2 with variation of the anode
voltage (Ua) from 0.2 to 6 kV. The pulse length was
20ms with an operating frequency of 50 Hz. A dimen-
sion of the spot on the target was near 7 mm. In the
chamber a vacuum of 10-5 Torr was provided by a crio-
getter pump [3].
λ , nm
350 500 550 600450400 650
500
0
1000
1500
2000
2500
3000
I, a.u
Fig. 1. The photoluminescence spectrum of the sam-
ple described.
Fig. 2. The installation for irradiation of samples
with electrons.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №3.
Серия: Ядерно-физические исследования (38), с. 173-174.
173
The relative luminous emmitance of samples was
measured at a current of the photomultiplier (Ph.M.-68).
One operated in the current regime in the range of its
maximum spectral response (∆λ=380-480 nm).
3 EXPERIMENTAL RESULTS AND DIS-
CUSSION
During investigations we measured the target current
and Ph.M. current as a function of the electron gun Ua at
the constant current on the target equal to 2 µA. The
typical oscillogram of the electron current on the sample
and the Ph.M. signal are shown in Fig. 3.
Fig. 3. Oscillograms of the electron current on the
sample (a) and the Ph. M current (b).
The average value of Ph.M. current versus anode
voltage is presented in Fig. 4.
U a , kV
0 3.0 4.0 5.02.01.0
1.0
2.0
3.0
6.0
I Ph.M. , µ A
Fig. 4. Photocurrent versus anode voltage of the elec-
tron gun. It=2 µA; Uph.M=900 V.
As is seen on this plot the distinguished signal origi-
nates already near 200 V. Then there is approximately a
linear growth and after 3-4 kV it is set in saturation.
The minimal starting current density of the electron
beam for a luminous emitting from our sample is 0.05 µ
A/cm2. The linear growth of the glow intensity with the
current density is observed to 4 µA/cm2.
The results obtained may be explained as follows. If
to suppose that a number of excitation acts is directly
proportional to the range of an electron path in a lu-
minophore layer, then the luminance of glow must de-
pend linearly on a depth of the electron penetration into
the layer. The depth of penetration may be estimated as
x=Cv4 (C is the constant, v is the electron velocity.
Since v~
aU (Ua the anode voltage), it is possible to
suppose that the luminance is proportional to the square
of accelerating voltage.
However in the Fig. 3 one can see that this depen-
dence is nearer for the linear one.
The estimation shows that the electron path on
Ua = 4 kV becomes larger then a film thickness of (1.0 µ
m) and they do not meet the excitation centers. The
Ph.M. current in the Fig. 3 gets the saturation.
Thus, the obtained experimental results on the exci-
tation of cathode luminescence in LB films apparently
can form the basis for more detailed research of lumi-
nous output optimization.
However it is possible to assume now, that LB films
may be used as a detector of the low-energy electrons
(β-particles). The conventional organic molecular sin-
gle-crystal detectors are low-effective in the low-energy
region.
REFERENCES
1. N.I.Voronkina, V.M.Zuber, N.A.Popova, A.V.Tol-
machov // Funktsionalnye materialy. 1994, v. 1, №
2, p. 139-141.
2. Japan Patent 63-101787.
3. A.L.Donde and A.N.L’vov // CRYOGENICS. Octo-
ber 1971, p. 408-409.
174
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