ISSS（TJ-SSFタイ政府主催科学フェア）参加報告
2015年度は国際交流事業ISSSとして、タイで開催されたサイエンスフェアである
TJ-SSF（Thailand-Japan StudentScience Fair 2015 “Seeding Innovations throughFostering Thailand-Japan Youth Friendship”）にサイエンス研究会4, 5年生5名が参加しました。化学班がサイエンス研究会を代表して、ポスター発表「Dye-sensitized solar
battery experiment」を行いました。
期間2015年12月20日(日)～24日(金)会場

Princess Chulabhorn Science High School Phetchaburi（以下、PCSHS-P）

参加校

日本25校、タイ41校

参加者

５年Ａ組

稲石大義、西本４年Ｃ組

出水明日香、中谷有里、４年Ｂ組

山田莉彩、駿介

日程（タイでの活動）
月日

訪問先等(発着)

時刻

実施内容

宿泊地

12/21

関西国際空港発

深夜TG673バンコク行き

生徒(月)

バンコク国際空港着早朝

バンコク到着寄宿舎

PCSHS-P

午後

PCSHS-P到着

教員

文化交流

ホテル

オープニングセレモニー

同上

12/22

PCSHS-P

午前

(火)
12/23

講演会
PCSHS-P

午後

ポスタープレゼンテーション

全日

口頭発表会（グループ別）

(水)

同上

ポスタープレゼンテーション
夜

天体観測

12/24

環境研究所

午前

フィールドトリップ(木)

PCSHS-P

午後

まとめ・発表12/25

PCSHS-P

3:40発

先方手配送迎車にて移動(金)

バンコク国際空港発

11:00発TG672関西空港行き直行便

関西空港着

18:10着帰国

このサイエンスフェアで化学班がポスター発表を行った「Dye-sensitized solar battery experiment」の概要が次ページにあります。英語でのプレゼンテーションを堂々と行い、タイの生徒とも積極的に交流しました。

同上Thailand – Japan Student Science Fair 2015
“Seeding Innovations through Fostering Thailand – Japan Youth Friendship”

Dye-sensitized solar battery
experimentIntroduction
Since the Great East Japan earthquake occurred,
nuclear power plants in Japan have been stopped
due to safety concerns, causing shortages ofpower in many regions. These days we have tosecure energy sources, and we realized that solar
power may be a solution.

NISHIMOTO Yuri
INAISHI Tomoki
Instructor MUSO Tomoko
Instructor KOSHINO Shozo
Nara Women’s University Secondary School,
Nara, 630-8305, Japan

Abstract
The organic dye-sensitized batteries werestudied. These batteries make voltage by titaniumoxide’s ability to absorb ultraviolet rays which
excites electrons to create charges. It is said that it
becomes possible to generate power by not only
ultraviolet rays but also by light whose
wavelength is longer than ultraviolet by mixing
organic dye with titanium oxide. By changing
how to make the titanium oxide paste and using
these properties, we expected to generate morevoltage. When we made the sample, we added
only Polyethylene glycol into the titanium oxide
paste and then heated the mixture, which changed
the thickness. To study the relationship between
the thickness and electromotive force, we heatedthem. However, the surface of the paste of thesample which contained only Polyethylene glycol
cracked and peeled off from the glass substrate
when it absorbed the dye, so it did not work as
expected. Then, we had doubts about themethodology of adding only Poly-ethylene glycol
to the paste and continued our research by
studying other methods of making the paste. So,
we decided that instead of focusing on the old wayof making the paste by using Polyethylene, wedecided to use acetic acid.
Keywords: dye-sensitizedtitanium oxide, acetic acidsolarbattery,

Solar batteries can generate semi-permanent
power in any location if there are the facilities
which are required. Solar power is different fromthermal power or nuclear power generation, and it
is good for the environment because it does notproduce any toxic gases or liquids. On the other
hand, current solar batteries are said to be
dangerous if the building in which it is locateddoes not meet the earthquake resistance standards,
so many wooden buildings are not suitable sites.
Furthermore, the color is dark, so places in whichthese can be located is limited. So we thought that
if we could produce a small, light, clear battery we
could position them in different places such as on
windows or walls and produce more electricity.
One type of solar battery, that we studied, that canachieve this purpose are dye-sensitized solar
batteries. Dye-sensitized solar batteries don’t
require expensive materials, can be made at low
cost, and plastic can be used as a base, so we canmake them lighter and smaller. With theseadvantages we can also place them where we can’t
place them now. In addition, we can make semitransparent or change its color, through altering
the pigments, some groups are investigating
alternative designs. For example, with a clear
solar battery, they can be placed on widows,
without impacting the view.
Last year we studied about the relationshipbetween a paste’s thickness and the electricity
which is generated. This year we changed thematerials of the paste, and determined that the best
condition is that of using fine crystals of TiO₂
which become a porous structure and the surface
area becomes larger which can absorb the pigment
better. This time we mixed Polyethylene glycol
which is a type of polymeric material into the TiO
₂ paste.

How to Produce Electricity

Figure 1
As shown in Figure 1, dye-sensitized solar
batteries are constructed by using a transparent
electrode organic pigment which absorbs visible
rays. The TiO₂’s porous structure which connects
the organic pigment electrolyte solution contains
I- and the opposite cathode which is covered bya black lead. This dye sensitive solar battery
principle of power generating occurs like this:
1. The organic pigment absorbs visible rayscausing the electronics which is in thepigment to excite and go into the TiO ₂coating.
2. The electrons on the transparent electrode
move to the opposite cathode through theoutside circuit.
3. I3- which is the electrode solution gets
additional electrons which have reached to theopposite cathode and change into I-.
4. On the other hand, the organic pigment whichlost electrons becomes oxidized and getselectrons from I- which are in the electrolyte
solution and regenerates.
When these reactions are constant, direct current
is produced. Because of these processes, dyesensitized solar batteries produce electricity fromlight.

Materials and Methods
The first step is to establish the best way toproduce TiO₂ crystals. The other factors, suchas the color of paste, should be considered afterthat.
The objective of the following three experiments
is to find the best TiO₂ crystal construction.
Overview
Experiment I
In the experiment I, the focus is to be put on thethe thickness of TiO ₂ paste coating thetransparent electrode.
We tested the pastes of three different thickness
with the three different heating powers.
We also used two different
temperaturesapprox.80 ℃ and 120℃ when baking the paste.
However we couldn’t collect reliable data. That’s
because we couldn’t make exact measurement of
the heating power .
Experiment II
In the experiment II, the focus is put on toestablish how the differences in thickness of thepaste and heating power used in making the paste
affect the amount of generated power. We
measured how much power is generated from thesix different batteries A to E with six different
pastes in thickness and heating power. Cracks on
the surface of the paste is to be examined.
Experiment III
After Experiment II, we realized the need of anadditional experiment, which is Experiment III.
That is because the result of Experiment II istotally different from our expectations. In
Experiment III, we tested three different
substances to be put in the paste. We measured thethree different batteries and measured how much
power is generated.
Experiment I
ObjectiveTo find the best thickness of the paste under somedifferent conditions
Hypothesis
The thinner paste has the less number of cracks.
Materials
The powder of TiO ₂ (8g), PEG(4g), Purewater(16g), Detergent (including 42% surface
active agent), Ethanol
Preparation(1) Produce TiO₂ paste[1.]Melt PEG in water[2.]
Make20% PEG solution.
[3.]
Churn TiO₂ and PEG for 30minutes.
[4.]
Put the mixture in the bottle with asyringe.
(2) Cleanse conducting glass with three kinds ofliquid: a) five fold dilution of detergent b)purewater c) ethanol•Pick the conducting glass with a tweezer andwash it by shaking it in the liquid.
•In the same way, cleanse the tweezer and theglass stick.

Thailand – Japan Student Science Fair 2015
“Seeding Innovations through Fostering Thailand – Japan Youth Friendship”

Procedure(1) Coat conducting glass
1. After washing the glass, stick tape as shownin Figure 2 on the conducting side.

Figure 2
2. After shaking the bottle, put the paste on theglass.
3. Make the thickness even and remove thebubbles by sliding the glass stick.
(2) Bake TiO₂ paste
1. Put the glass with the paste on the stainlessboard not to be heated directly. In addition,
put the windshield around the glass.
2. Bake it by Gus burner for 20 minutes.
3. Cool it to normal temperature for 15
minutes.
Below is the tale to indicated the combination of
the different thicknesses and the different heating
powers.

Table 1
Observation
Several cracks were spotted on the surface ofevery paste.

Figure 3
We observed the size and condition with an
optical microscope. Below is the sketch of themon Figure 3, and the graph about crack’s size onFigure 4.

Figure 4
Experiment II
Objective
To confirm that the paste with the fewer cracks
produces the larger amount of electricity
Hypothesis
The paste with the fewer cracks produces thelarger amount of electricity.
Materials
Pentax of mallow blue (0.5g), Pure water (20ml),
Electrolyte solution which include Iodide ion,Pencil (6B)
Preparation(1) Dye extraction
1. Added water 20ml to Pentax of mallow blue
and left it for 10minutes.
2. Take out the Pentax with squeezing.
(2) Adsorption
Take the pigment by a tweezer , put it on the TiO
₂ coat 3 or 4 drops and left it for 10 minutes.
(3) Making of electrodes
Coat the conduction surface by painting with apencil, holding the glass with a tweezer.
(4) Building batteries
1. Put the glass with black lead on the glass
covered with TiO ₂ paste and absorbed
pigment.
2. Hold an edge with a clip.
3. Add a couple of drops of electricity solutions
from the other edge and hold the other end
with a clip fasted.
Procedure1. Measure the amount of the power generated
by the batteries from A to B. We measured
their reverse voltage and resistance in twosituations, without light and with LED’s lightfrom the distance.
2. Measure the amount of electricity generated
from the pairs of the batteries. Because of thelack of equipment, we couldn’t measure thesix different batteries simultaneously, so wemeasured the three different pairs(AB,CD,EF) at the same time on differentdays.
3. In addition we grouped the six batteries into
two groups in terms of the sun light angles:
ABEF and CD. They have the totally opposite
angles.
4. We also made a difference between ABCD
and EF in terms of the timing to measure after
pouring electrolyte solution.
5. We measured batteries A, B, C and D incouple of hours after pouring it. On the other
hand we measured batteries E and F threedays after pouring it.
Observation
Measuring the batteries individuality
The table shows that the resistance value isn’t
stable. We recorded the maximum and theminimum. In the left side is the minimum, and in
the right side is maximum.
Date：A～D 12/25 12:30 cloudy
E,F 12/22 15:30

Without light, Most of their electromotive values
are near 0mV, and only in the battery wemeasured 5.0. There is a stark contrast between Fand the other batteries.
Under the LED light, most of them changed
positive cathode from the side of black lead to theside of TiO₂ coats .
Under the sun light, the side of black lead became
the active cathode. With LED light, theresistances inside the batteries became a littlesmaller, and with sunlight, it became very smaller.
Measuring in same date and time
Date:12/25 14:45～ cloudy

Figure 5

Figure 6

Thailand – Japan Student Science Fair 2015
“Seeding Innovations through Fostering Thailand – Japan Youth Friendship”

Figure 7

Figure 8
The graphs 5-8 show the amount of electricity
generated under several conditions. The battery
A produced electricity but the battery B produced
little. (Figure 5)Both of the batteries C and D
produced electromotive force and the battery D
produced more. (Figure 6)
The batteries of larger number of crackers
produced the less amount of electricity. Inaddition, when we shined from the side of blacklead, the active cathode changed from theoriginally side and became the TiO ₂side.(Figure7) The electromotive force of thebatteries E and F without the light was far from0mV.(Figure 8)
Experiment III
Overview
As shown in Figure 5-8, we measured the opposite
direction of electricity against our expectations.
So we decided to make an additional experiment.

We guessed that the temperature is closely relatedwith the peeling off. So we raised the heating
temperature to 450 ℃ . As a result of theexperiment it turned out that the temperature is notthe culprit. That’s because we couldn't see a big
difference
betweenthetwodifferent
temperatures. From this comes an inference thatother factors are involved.
Objective
To find the best substance to be put in the paste inorder to make the battery more effective
To confirm what is the best of the substances, suchas, acetic acid and PEG or the combination.
To confirm that TiO₂ peeled off when we poured
electrolyte solution, which adverse the electric
current.
Materials
7.5g of powdered TiO₂ , 15g of pure water, PEG
Preparation
Make three types of TiO₂ paste
1. The paste which includes only pure water.
Mix the 7.5g of powdered TiO₂ and purewater 15g for 30 minutes
2. The paste which includes only acetic acida. Make acetic acid 3% aqueous solution
b. Mix 15g of the Acetic acid solution and7.5g of the powdered TiO ₂ for 30
minutes
3. The paste which includes acetic acid andPEG. Mix 7.5g of powdered TiO₂ , 15g ofacetic acid 15g and 4g of PEG4g for 30
minutes.
Procedures
1. Put the paste on the glass
2. Put the paste in the same way as theexperiment I.
3. Bake TiO₂ paste
4. We heated the glass covered with TiO₂ paste
in electric furnace in 450c for 15 minutes.
5. Get together and absorb dye
6. We took them together like the experimentⅢ.
7. Power generation experiment
8. We measured electromotive force of threekinds under three situations; sunlight,
fluorescent lamp and no light
Observation
All of three batteries measured the biggest number
immediately after started measuring and kept thenumber around minimum number. The battery(1) took very different number from others, so
there might be something wrong when wemeasured.

effective battery, it is crucial to make the paste asthin as possible.
As for the substance to be used in making thepaste, the use of both acetic acid and PEG is themost effective.
The types of light are also a very important factor
to be considered. Under the fluorescent lamp, thebattery produces less electricity than under thesun. That’s because the fluorescent light includes
less shorter-wavelength under ultraviolet rays.

Further challenge
A stable and effective battery requires electrolyte
to exist as long as possible without evaporating. It
might be possible to lower the melting point ofelectrolyte but it is also important to devise a good
way of preventing electrolyte from evaporating.
We also need to establish what color of dye is themost effective and how the dye is put in the paste.
In these experiments we coat the solid paste withthe dye. Another alternative is to put the dye in thepaste material before it is put into a mold.

A cknowledgment
We are grateful to Mr. Koshino and Ms. Muso for
helpful advice and support.

Conclusions
From these results, we confirmed that thethinner paste produces the larger amount ofelectricity. At the same time we find that the mostimportant factor to make an effective battery is thenumber of cracks on the surface of the paste. The
thinner paste produces the fewer number of thecracks on the surface. In order to make an