CC BY
33
UDC 678.046:535.372
A. E. Ivanitskiy, V. S. Raida, A. S. Minich, G. A. Ivlev
RESEARCH OF PROPERTIES OF PHOTOLUMINESCENT FILMS AT EXCITATION
BY A SOLAR RADIATION
The fluorescen properties of polyethylene photoluminescent films connected with injecting to their composition of photoluminophor on the basis of linkings of europium in excitation of UV by radiation of the sun are investigated. For the first time experimental measurement of rates of fluorescent radiation of a photoluminescent film at its exploitation in natural conditions are carried out. The maximum values of fluorescence intensity of films in investigated conditions make near to 8 mW/m2, average day from 0.5 to 2 mW/m2. For the first time the received results have allowed to make a quantitative estimation of fluorescent radiation intensity of photoluminescent films at effective cultivation under them plants in natural conditions. Reproducing of such indices can allow transferring effect studying to controllable laboratory conditions.
Key words: the polymeric, fluorescent, agricultural films; optical properties.
Introduction
The polymeric films possessing photofluorescent properties, are widely used for protection constructions of the sheltered ground in agriculture [1]. The polyethylene films modified by additives of organic and inorganic photoluminophors on the basis of linkings of europium (photoluminescent), have been produced by Russian industry from the middle of 90th years. Intensive increase of industrial output of such films is defined by unique consumer properties of photoluminescent films. At the beginning of 80th years it was shown [2], that using of such films in order to protect constructions of the sheltered ground allowed to considerable increase productivity, to reduce terms of cultivation of cultures in comparison with films of other classes. Numerous testing in various regions of Russia and other countries on the areas to 100 hectares on a wide range of agricultural and decorative cultures [1-4] are conducted. Test data show, that the specified effect termed “polisvetan”, is enough universal.
The use of photoluminescent films allows to increase productivity of the sheltered ground by 1090 % and to reduce terms of plants cultivation to 1-3 weeks. However the effect can be negative and it’s defined by specific and varietal accessories of grown plants, photophysical properties of photoluminescent films, climatic conditions and many other factors [1, 2]. Successful realization of this effect is defined by composition and fluorescent properties of films and, in not a less degree, meteorological conditions in operating period (first of all, intensity of UV radiation of the sun and intensity of fluorescent radiation of films dependent on it). At this time in literature there are no data of intensity values of fluorescent radiation of films in natural conditions and procedures of their direct experimental measuring in conditions of the sheltered ground in plants cultivation under them.
Previously we have undertaken an attempt of definition of fluorescent radiation intensity of photoluminescent films. It is made with using of transformation
coefficients by films UV radiation, received in laboratory requirements, and to values of UV radiation intensity of the sun, spotted in the middle of the day by means of UV radiometer to clear sunny days [5]. Such approach has allowed to obtain data on the order of fluorescent radiation intensity of a photolumi-nescent film in natural conditions, typical for Tomsk region. The further development of operation in this direction is related to comparison of fluorescence intensity of films and efficiencies of cultivation under them plants for the purpose of definition of its quantity, optimum for plants development. The solution of this problem is obstructed by impossibility of direct experimental definition of quantity against the background on three orders of more intensive and continuously chaotic changing sunlight of the same spectral range.
In the present paper we offer an approach to definition of quantities of fluorescent radiation intensity of photoluminescent films which consists in continuous measuring of values of UV radiation intensity of the sun, definition of film fluorescence intensity by the instrumentality of them daily all through cultivation of plants under a film in natural conditions.
Experimental
In the capacity of experimental photoluminescent film of polyethylene of high pressure (LDPE) with the additive of an organic photoluminophor most typical for such films on the basis of a complex of europium nitrate with 1,10-fenantrolin (FE), with a maximum in a luminescent spectrum 617 nm is used. Film was made of polyethylene of high pressure of the mark 15303-003 by standard method of blown extrusion by procedure [6].
Quantities of diurnal intensity of solar radiation in UV region are determined with use of values of two devices of Station of high-rise sounding of Institute of optics of atmosphere of the Siberian Branch of Russian Academy of Science (TOR station, Tomsk): ultraviolet pyranometer UVB-1 of firm YES (Yankee
environmental system, inc. USA) with range from 280 to 320 nm, giving out integrated value in range B and spectrophotometer Brewer MKIV (Canada), which scans total radiation with a step of 0.5 nm in range from 290 to 325 nm. Restoration of a spectrum of UV radiation in range from 325 to 400 nm was carried out on a procedure used for ultra-violet and ozonemetric stations on the basis of devices Brewer taking into account a spectral window on a wave length 324 nm and the assignment of a model spectrum to 400 nm. The obtained data of UV radiation intensity of the sun allow to calculate film fluorescence taking into account transformation coefficients of radiation. Thus, maximum values of intensity of fluorescent radiation of photoluminescent film for each day and average day intensities as an arithmetic means are received during the test operation [5].
Biological trials were made with using early procedures of biological testing of light adjusting films developed by us, consisting in cultivation of white cabbage seedling in conditions of the sheltered ground in spring time [7, 8]. After 30 days of plants cultivation (from 1st till 31st of May,) morphometric rates of plants, grown under light adjusting films were compared with similar rates of plants, grown under not modified polyethylene films with the same technological parameters by procedures [7, 8].
In the work data of observations of meteorological conditions (cloudiness) of a local hydrometeorological station of Tomsk also are used.
Results and discussion
The photoluminescent film used in this work has typical for such class of materials photophysical properties (Tab. 1).
Table 1
Some properties of a polyethylene photoluminescent film (from a LDPE of a brand 15803-020) thickness of 0.120 mm with the additive of 0.1 % mass a luminophore
Lumino- phore type Spectral distribution of luminescent radiation, nm Breadth at semialtitude of the basic peak, nm Coefficient of specific conversion [5]
FE 597;617; 685 3.05 ± 0.05 5.2-10-5
* - the basic strip in a luminescent spectrum is emphasized.
For definition of fluorescent radiation intensity of a photoluminescent film in natural conditions we use coefficients of transformation defined earlier in laboratory conditions [5]. Intensity of UV radiation of the sun exciting fluorescence is defined within each day during the period from 1st till 31st of May, 2003 in region of Tomsk. As an example on Fig. 1 data on change of UV radiation intensity within several days are presented.
UV radiation intensity of the sun has typical daily changes (uniform increase since morning in the forenoon and reduction by the evening) [5] and also has local changes during the day which conform with cloudiness level. At cloudy weather intensity of UV radiation reduces and increases during fair weather.
Data on intensity of UV radiation of the sun have allowed to find the maximum day values and calculate average day values of intensity of UV radiation as arithmetic mean.
Time, hour
Fig. 1. Day change of intensity of a UV of radiation (290-400 nm) in May, 2003 (numbers of curves correspond to dates of May, 2003)
On Fig. 2 data on change of intensity of UV radiation of the sun and meteorological conditions in region during all period of carrying out of test are presented.
1 6 11 16 21 26 31
Days of month
Fig. 2. Values of intensity of solar radiation of UV area and meteorological conditions in test carrying out (May, 2003): 1 - overcast;
2 - a day maximum; 3 - average day intensity
Use of the got values of day intensity of a UV of radiation of the sun, allows to calculate maximum and midday intensity of fluorescent radiation of a photoluminescent film, for each day of carrying out of tests.
As an example on Fig. 3 data on day dependence of fluorescent radiation intensity of photoluminescent film with luminophore FE with a maximum in the region of 617 nm for several days of May, 2003 (data correspond to intensity of an exciting UV radiation on Fig. 1) are presented.
mass luminophore FE and meteorological conditions during the tests are presented (May, 2003).
Fig. 3. Intensity of fluorescent radiation of a photoluminescent film with the additive of 0.1 % mass luminophore FE during the day in May, 2003 (numbers of curves correspond to calendar dates)
Earlier it was shown, that in exploitation of photo-luminescent films in natural conditions significant reduction of fluorescence intensity of luminophores in films proportional to their life time is observed and it’s connected with photochemical destruction of lu-minophore in a film [9] and result in regular reduction of fluorescent radiation intensity of a film at identical intensities of excitant UV radiation. Such regularity of service of an investigated film requires introduction of correction coefficients into values of fluorescence intensity of a photoluminescent film. Such coefficients are proportional to degree of photochemical decomposition of luminophores in film and for an investigated film they are defined earlier by us [1G].
As an example in Fig. 4 data on change of value of day intensity of fluorescent radiation of a photolumi-nescent film with luminophore FE, corresponding to data of Fig. З, calculated taking into account transformation ratio reduction are presented.
Fig. 4. Day changes of fluorescent radiation intensity of a photoluminescent film with the additive of 0.1 % mass luminophore FE corrected on coefficient of photochemical decomposition of luminophore in May, 2003 (numbers of curves correspond to calendar dates)
On Fig. 5 values of fluorescent radiation intensity of a photoluminescent film with the additive of G.1 %
Days of month
Fig. б. Values of fluorescent radiation intensity of a photoluminescent film with the additive of 0.1 % mass luminophore FE and meteorological conditions in test carrying out (May, 2003): 1 - overcast; 2 - a day
maximum of fluorescent radiation; 3 - average day intensity of fluorescent radiation
Thus, for the first time experimental measurement of rates of fluorescent radiation of a photoluminescent film at its exploitation in natural conditions are carried out. The maximum values of fluorescence intensity of films in investigated conditions make near to 8 mW/ m2, average day from G.5 to 2 mW/m2.
Biological testing of photoluminescent film was made at the same season (May, 2GG3) by cultivation of white cabbage seedling of a kind “Nadezhda” and definition of morphometric rates- the areas of leaves, green and dry mass for 3G-day plants [7]. Rates of control plants cultivated in the same conditions under not modified polyethylene films were used as comparison.
In 2GG3 for the plants cultivated under trial film, substantial increase of these indexes in comparison with indexes of control plants is noted. So, the area of plants leaves is more by 9G %, green mass - 113 %, dry mass - 85 % under trial films than under control.
In May, 2GG3 daily measurements of fluorescent radiation intensity of a photoluminescent film were carried out and significant acceleration of growth and development of test plants was observed.
Thus, for the first time experimental data by direct definition of values of fluorescent radiation intensity of a photoluminescent film are received in natural conditions giving the chance of successful realization of “polisvetan” effect.
Conclusion
The technique of definition of day fluorescent radiation intensity of photoluminescent films in the conditions of a sheltered ground is offered.
On an example of cultivation of cabbage seedling comparison of data of fluorescent radiation intensity of a photoluminescent film in concrete meteorological conditions and efficiency of film influence on growth
and plants development is made in spring time of tion intensity of photoluminescent films at effective
2003. cultivation under them plants in natural conditions.
For the first time the received results have allowed Reproducing of such indices can allow transferring ef-
to make a quantitative estimation of fluorescent radia- fect studying to controllable laboratory conditions.
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Ivanitskiy A. E.
Tomsk State Pedagogical University.
Ul. Kievskaya, 60, Tomsk, Russia, 634061.
Raida V. S.
Tomsk State Pedagogical University.
Ul. Kievskaya, 60, Tomsk, Russia, 634061.
Minich A. S.
Tomsk State Pedagogical University.
Ul. Kievskaya, 60, Tomsk, Russia, 634061.
Ivlev G. A.
Institute of Atmospheric Optics SB RAS
Pl. Academician Zuev, 1, Tomsk, Russia, 634012.
E-mail: [email protected]
Received 14.03.2011.
А. Е. Иваницкий, В. С. Райда, А С. Минич, Г. А Ивлев ИССЛЕДОВАНИЕ СВОЙСТВ ФОТОЛЮМИНЕСЦЕНТНЫх ПЛЕНОК ПРИ ВОЗБУЖДЕНИИ СОЛНЕЧНЫМ ИЗЛУЧЕНИЕМ
Исследованы флуоресцентные свойства полиэтиленовых фотолюминесцентных пленок, связанные с введением в их состав фотолюминофора на основе комплексного соединения европия при возбуждении УФ излучением солнца. Впервые экспериментальным путем проведено измерение показателей флуоресцентного излучения фотолюминесцентной пленки при ее эксплуатации в естественных условиях. Максимальные значения интенсивности флуоресценции пленок в исследованных условиях составляют около 8 мВт/м2, среднедневная от 0.5 до 2 мВт/м2. Полученные результаты позволили впервые провести количественную оценку интенсивности флуоресцентного излучения фотолюминесцентных пленок при эффективном выращивании под ними растений в естественных условиях. Воспроизведение таких показателей может впервые позволить перенести изучение эффекта в контролируемые лабораторные условия.
Ключевые слова: пленки полимерные, флуоресцентные, сельскохозяйственные; оптические свойства.
Иваницкий А. Е., кандидат технических наук.
Томский государственный педагогический университет.
Ул. Киевская, 60, Томск, Россия, 634061.
Райда В. С., кандидат технических наук.
Томский государственный педагогический университет.
Ул. Киевская, 60, Томск, Россия, 634061.
Минич А. С., кандидат химических наук, доцент.
Томский государственный педагогический университет.
Ул. Киевская, 60, Томск, Россия, 634061.
Ивлев Г А.
Институт оптики атмосферы им. В. Е. Зуева СО РАН.
Пл. академика Зуева, 1, Томск, Россия, 634012.
E-mail: [email protected]
