rus
Issue #2/2021
O.A.Farus
Antireflective coatings based on polymer films with silver nanoparticles for solar cells
Antireflective coatings based on polymer films with silver nanoparticles for solar cells
DOI: 10.22184/1993-8578.2021.14.2.120.126
The work is devoted to obtaining and evaluating the effectiveness of film antireflection coatings for solar cells based on silver nanoparticles. The development aim of antireflection coatings is to reduce reflection of electromagnetic waves of visible and infrared light. The illumination effect is achieved by applying a polymer solution containing silver nanoparticles on the surface of the solar battery, which turns into a thin film in 24 hours. The coating was synthesized by the sol-gel method. The advantage of the considered coatings lies in the simple hardware design of their production. The comparative analysis of the solar cells efficiency showed that the modification of the solar battery with an antireflection coating increases its efficiency by 9.5%.
The work is devoted to obtaining and evaluating the effectiveness of film antireflection coatings for solar cells based on silver nanoparticles. The development aim of antireflection coatings is to reduce reflection of electromagnetic waves of visible and infrared light. The illumination effect is achieved by applying a polymer solution containing silver nanoparticles on the surface of the solar battery, which turns into a thin film in 24 hours. The coating was synthesized by the sol-gel method. The advantage of the considered coatings lies in the simple hardware design of their production. The comparative analysis of the solar cells efficiency showed that the modification of the solar battery with an antireflection coating increases its efficiency by 9.5%.
Теги: anti-reflection coating efficiency polymer films silver nanoparticles solar battery sol-gel technology volt-ampere characteristic вольт-амперная характеристика золь-гель-технология коэффициент полезного действия наночастицы серебра полимерные пленки просветляющее покрытие солнечная батарея
ANTIREFLECTIVE COATINGS BASED ON POLYMER FILMS WITH SILVER
NANOPARTICLES FOR SOLAR CELLS
O.A.Farus*, Cand. of Sci. (Chemical), Docent
DOI: 10.22184/1993-8578.2021.14.2.120.126
Получено: 08.04.2021 г.
The work is devoted to obtaining and evaluating the effectiveness of film antireflection coatings for solar cells based on silver nanoparticles. The development aim of antireflection coatings is to reduce reflection of electromagnetic waves of visible and infrared light. The illumination effect is achieved by applying a polymer solution containing silver nanoparticles on the surface of the solar battery, which turns into a thin film in 24 hours. The coating was synthesized by the sol-gel method. The advantage of the considered coatings lies in the simple hardware design of their production. The comparative analysis of the solar cells efficiency showed that the modification of the solar battery with an antireflection coating increases its efficiency by 9.5%.
INTRODUCTION
Traditional energy sources, such as gas, oil or coal deplete year by year while energy consumption is growing due to increased human population. As the energy reserve of the Earth reduces at an ever increasing rate, the price of 1 kW is growing every year. That leads to a necessity to look for new renewable energy resources, i.e. alternative energy sources. One of the most promising alternative energy sources is the Sun light. The high competitiveness of the Sun light as a source of energy is due to its universal accessibility in any point of the Earth’s surface [1, 2]. According to literary data, 1 m2 area accounts for 1,367 W / m2 of solar radiation [4].
The solar battery performance is based on the photovoltaic effect, which was discovered by Alexander Edmond Becquerel in 1839. The first solar battery module was constructed by Charles Fritz 44 years later. There are various types of solar panels. Nowadays, photocells based on thin silicon plates are most popular. Currently, solar panels are used in many areas, for example, in medicine, space industry, telecommunications and others [7].
It is necessary to understand that many processes lead to decreasing of the solar cells efficiency. One of the greatest losses occurs due to reflection of light from the semiconductor surface. One way to reduce losses is to apply an interference enlightening cover on the solar battery glass surface. The enlightening coating is a special kind of coatings which refractive index is lower than the refractive index of glass [4].
RESEARCH METHODS
During the study, an antireflective coating was developed on the basis of an artificial water-soluble polymer – polyvinyl alcohol (PVA) and silver nanoparticles. The coatings were obtained by sol-gel technology [8].
The coating was made on the basis of a dry polyvinyl alcohol ((C2H4O)x, where x is the degree of polymerization), silver nitrate (AgNO3) and ascorbic acid (C6H8O6). The polyvinyl alcohol was diluted with water and heated while being constantly stirred until the transparent liquid is formed. After that, a solution of silver nitrate was introduced into the resulting liquid and the ascorbic acid solution was added while constant stirring.
C6H8O6 + 2AgNO3 =
= 2Ag + C6H6O6 + 2HNO3.
A part of the resulting solution was transferred to Petri dishes for the formation of films, which were further studied using a spectrophotometer, and another part was applied to the solar battery glass cover. To obtain films of the same thickness, the solutions were selected with the aid of measuring pipettes.
Evaluation of the optical properties of the resulting coating was carried out using the two-bearing Area 303UV spectrophotometer. The spectra of transmission and absorption were obtained in the range from 190 to 900 nm with step of 5 nm (Fig.1).
A comparative analysis of the obtained absorption and transmission spectra shows their mirror and presence of two small maxima at wavelengths 220 and 470 nm correspondingly. This indicates the ability of applied coating to reduce percentage of the reflected light [3, 9].
RESULTS AND THEIR DISCUSSION
To assess efficiency of the obtained coating, the basic parameters of the solar battery were evaluated before and after applying the antireflective coating.
As an object of study, the "Blooma" solar battery for garden lighting was chosen. At the initial stage of the experiment with permanent illumination (was determined using a luxmeter), a load volt-ampere characteristic (VAC) was determined. In so doing, the current (In) in the photocell circuit was measured while the resistance (Rn) was being changed (Table 1).
The volt-ampere diagram was constructed on the basis of the experimental data obtained (Fig.2).
Analysis of the diagram shows that the solar element before the modification has the following parameters:
The resulting volt-ampere characteristic allows of calculating the maximum power of the solar battery, which is equal to the area of the dashed rectangle in Fig.1. The area of this rectangle can be found according to formulas 1, 2:
W =Im ∙ Um; (1)
W = 11.3 ∙ 10–3 ∙ 2 = 0.0226 W. (2)
Also, at the first stage of the experiment the dependencies of voltage and current produced by the solar battery versus illumination were constructed (Fig.3).
Analysis of the obtained graphs shows that with an increase of power there is an increase in the current and voltage. The obtained data based on the VAC enabling to calculate efficiency of the investigated solar battery (formulas 3–7).
, (3)
here η – solar battery efficiency;
Sphotocell = a ∙ b, m2; (4)
S= Sphotocell ∙ n, m2, (5)
where n – quantity of photo cells;
Sphotocell = 4 ∙ 4 = 16 (см2) =
= 0.0016 m2; (6)
. (7)
Thus, we have assessed the initial parameters of the solar battery used in everyday life for garden lighting. The efficiency of this battery lies within 20-23%, which is well consistent with the literal data [2].
Similar parameters were determined for the solar battery after applying an antireflective coating. The obtained experimental data have been entered in Table 2.
Based on the obtained experimental data the VAC of the modified solar battery was constructed (Fig.4).
Analysis of the obtained graph indicates that the solar element after modification is characterized by the following parameters:
Float voltage (Uxx) – 5.5 V;
Short circuit current (Isc) – 14.5 mA
Maximum capacity (power) voltage (U) – 2.4 V
Maximum power current (I) – 13.2 mA
The resulting volt-ampere characteristic enables to calculate the maximum power of the solar battery (formula 8), which is equal to the area of the dashed rectangle in Fig.4:
W = 13.2 ∙ 10-3 ∙ 2.4 = 0.03168 W. (8)
In accordance with the obtained data, the efficiency of the solar battery after modification was calculated:
. (9)
The obtained results allowed of making a comparative analysis of the battery power before and after modification (Fig.5).
On the basis of the obtained results, it is clear that modification of solar cells leads to decreasing of solar cells reflectivity and, as a result, to increasing of power by 0.5 W.
CONCLUSIONS
The presented method of synthesizing the antireflective coating is a profit-proved technology due to absence of the need in expensive equipment. Introduction of nanoparticles in the polymer matrix leads to appearance of the absorption band in the region of 470 nm, which corresponds to the plasmon resonance of silver nanoparticles. The analysis of the load volt-ampere characteristic and power of the solar battery before and after modification of the synthesized films demonstrates that the solar cells efficiency increases after modification which indicates its effectiveness. ■
Declaration of Competing Interest. The author declares that he has no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
NANOPARTICLES FOR SOLAR CELLS
O.A.Farus*, Cand. of Sci. (Chemical), Docent
DOI: 10.22184/1993-8578.2021.14.2.120.126
Получено: 08.04.2021 г.
The work is devoted to obtaining and evaluating the effectiveness of film antireflection coatings for solar cells based on silver nanoparticles. The development aim of antireflection coatings is to reduce reflection of electromagnetic waves of visible and infrared light. The illumination effect is achieved by applying a polymer solution containing silver nanoparticles on the surface of the solar battery, which turns into a thin film in 24 hours. The coating was synthesized by the sol-gel method. The advantage of the considered coatings lies in the simple hardware design of their production. The comparative analysis of the solar cells efficiency showed that the modification of the solar battery with an antireflection coating increases its efficiency by 9.5%.
INTRODUCTION
Traditional energy sources, such as gas, oil or coal deplete year by year while energy consumption is growing due to increased human population. As the energy reserve of the Earth reduces at an ever increasing rate, the price of 1 kW is growing every year. That leads to a necessity to look for new renewable energy resources, i.e. alternative energy sources. One of the most promising alternative energy sources is the Sun light. The high competitiveness of the Sun light as a source of energy is due to its universal accessibility in any point of the Earth’s surface [1, 2]. According to literary data, 1 m2 area accounts for 1,367 W / m2 of solar radiation [4].
The solar battery performance is based on the photovoltaic effect, which was discovered by Alexander Edmond Becquerel in 1839. The first solar battery module was constructed by Charles Fritz 44 years later. There are various types of solar panels. Nowadays, photocells based on thin silicon plates are most popular. Currently, solar panels are used in many areas, for example, in medicine, space industry, telecommunications and others [7].
It is necessary to understand that many processes lead to decreasing of the solar cells efficiency. One of the greatest losses occurs due to reflection of light from the semiconductor surface. One way to reduce losses is to apply an interference enlightening cover on the solar battery glass surface. The enlightening coating is a special kind of coatings which refractive index is lower than the refractive index of glass [4].
RESEARCH METHODS
During the study, an antireflective coating was developed on the basis of an artificial water-soluble polymer – polyvinyl alcohol (PVA) and silver nanoparticles. The coatings were obtained by sol-gel technology [8].
The coating was made on the basis of a dry polyvinyl alcohol ((C2H4O)x, where x is the degree of polymerization), silver nitrate (AgNO3) and ascorbic acid (C6H8O6). The polyvinyl alcohol was diluted with water and heated while being constantly stirred until the transparent liquid is formed. After that, a solution of silver nitrate was introduced into the resulting liquid and the ascorbic acid solution was added while constant stirring.
C6H8O6 + 2AgNO3 =
= 2Ag + C6H6O6 + 2HNO3.
A part of the resulting solution was transferred to Petri dishes for the formation of films, which were further studied using a spectrophotometer, and another part was applied to the solar battery glass cover. To obtain films of the same thickness, the solutions were selected with the aid of measuring pipettes.
Evaluation of the optical properties of the resulting coating was carried out using the two-bearing Area 303UV spectrophotometer. The spectra of transmission and absorption were obtained in the range from 190 to 900 nm with step of 5 nm (Fig.1).
A comparative analysis of the obtained absorption and transmission spectra shows their mirror and presence of two small maxima at wavelengths 220 and 470 nm correspondingly. This indicates the ability of applied coating to reduce percentage of the reflected light [3, 9].
RESULTS AND THEIR DISCUSSION
To assess efficiency of the obtained coating, the basic parameters of the solar battery were evaluated before and after applying the antireflective coating.
As an object of study, the "Blooma" solar battery for garden lighting was chosen. At the initial stage of the experiment with permanent illumination (was determined using a luxmeter), a load volt-ampere characteristic (VAC) was determined. In so doing, the current (In) in the photocell circuit was measured while the resistance (Rn) was being changed (Table 1).
The volt-ampere diagram was constructed on the basis of the experimental data obtained (Fig.2).
Analysis of the diagram shows that the solar element before the modification has the following parameters:
- float voltage (Uxx) – 4.5 V;
- short circuit current (Isc) – 13.8 mA;
- maximum capacity (power) voltage (U) – 2.0 V;
- maximum power current (I) – 11.3 mA.
The resulting volt-ampere characteristic allows of calculating the maximum power of the solar battery, which is equal to the area of the dashed rectangle in Fig.1. The area of this rectangle can be found according to formulas 1, 2:
W =Im ∙ Um; (1)
W = 11.3 ∙ 10–3 ∙ 2 = 0.0226 W. (2)
Also, at the first stage of the experiment the dependencies of voltage and current produced by the solar battery versus illumination were constructed (Fig.3).
Analysis of the obtained graphs shows that with an increase of power there is an increase in the current and voltage. The obtained data based on the VAC enabling to calculate efficiency of the investigated solar battery (formulas 3–7).
, (3)
here η – solar battery efficiency;
Sphotocell = a ∙ b, m2; (4)
S= Sphotocell ∙ n, m2, (5)
where n – quantity of photo cells;
Sphotocell = 4 ∙ 4 = 16 (см2) =
= 0.0016 m2; (6)
. (7)
Thus, we have assessed the initial parameters of the solar battery used in everyday life for garden lighting. The efficiency of this battery lies within 20-23%, which is well consistent with the literal data [2].
Similar parameters were determined for the solar battery after applying an antireflective coating. The obtained experimental data have been entered in Table 2.
Based on the obtained experimental data the VAC of the modified solar battery was constructed (Fig.4).
Analysis of the obtained graph indicates that the solar element after modification is characterized by the following parameters:
Float voltage (Uxx) – 5.5 V;
Short circuit current (Isc) – 14.5 mA
Maximum capacity (power) voltage (U) – 2.4 V
Maximum power current (I) – 13.2 mA
The resulting volt-ampere characteristic enables to calculate the maximum power of the solar battery (formula 8), which is equal to the area of the dashed rectangle in Fig.4:
W = 13.2 ∙ 10-3 ∙ 2.4 = 0.03168 W. (8)
In accordance with the obtained data, the efficiency of the solar battery after modification was calculated:
. (9)
The obtained results allowed of making a comparative analysis of the battery power before and after modification (Fig.5).
On the basis of the obtained results, it is clear that modification of solar cells leads to decreasing of solar cells reflectivity and, as a result, to increasing of power by 0.5 W.
CONCLUSIONS
The presented method of synthesizing the antireflective coating is a profit-proved technology due to absence of the need in expensive equipment. Introduction of nanoparticles in the polymer matrix leads to appearance of the absorption band in the region of 470 nm, which corresponds to the plasmon resonance of silver nanoparticles. The analysis of the load volt-ampere characteristic and power of the solar battery before and after modification of the synthesized films demonstrates that the solar cells efficiency increases after modification which indicates its effectiveness. ■
Declaration of Competing Interest. The author declares that he has no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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