SCIENCE, ENGINEERING, AND TECHNOLOGY OF DYE SENSITIZED SOLAR CELLS: A DIDACTICAL DESIGN BASED ON TECHNOCHEMISTRY EDUCATION

This research was conducted to build a view of the nature of science and technology (VNoST) chemistry education student’s ability through the didactical design reconstruction. The material taken is Dye-Sensitized Solar Cells (DSSCs) topic with technochemistry education model. It is a model that looked at education from the perspective of engineers and scientists who work not only on inquiry but also on a design perspective. Based on literature research, Indonesian students had low academic literacy performance as revealed in PISA (Program for International Student Assessment) study from 2000-2015. This problem can be caused by a weak teacher's abilities of the nature of science and technology (VNoST). This research's method is Research and Development (R&D) through the Model of Educational Reconstruction (MER). The instruments used were the VNoST questionnaire, interview guidelines, and content analysis guidelines. This study's subjects were 25 prospective chemistry education students in the 6th semester for pre-conception study and ten students for implementation study at one of State Universities in Indonesia. The didactical design of learning that has been developed had several advantages, including the prediction of student responses and the anticipation of educators as well as the essential material that is a barrier to student learning. Analysis of the VNoST understanding construction patterns is explored further so that the reasons that underlie students in defining science and technology and their relationship are obtained. The implementation study proved that understanding VNoST students after attending didactical design learning improved by changing students' views on science and technology to be more accurate.


INTRODUCTION
Today's demands bring around people that living in the 21 st century must be equipped with various thinking skills. PISA (Programme for International Student Assessment) have done a lot of research concerned with science literacy assessment. The result shows that Indonesian students did not in line with these demands.
Thus, between 2002-2015, Indonesian students are still at a low level in mastering science literacy. For instance, a study in 2015 showed that only 1.6% of students could work effectively with situations and problems involved explicit phenomena that require them to make conclusions about the role of science or technology (OECD, 2016).
That's problem needs to be seen as a serious problem and must be looking for a good and comprehensively solution. Vesterinen et al. (2013) and Tala (2013) propose that the solution can be started from teachers to be master like science and technology (Nature of Science and Technology, NoST) as the primary and vital element of science literacy. Science teachers who do not comprehend NoST will be challenging to teach and help learners gain a good understanding of science concepts (Tairab, 2011).
According to Tala (2013) and Chamizo (2013), in order to build a better comprehending of NoST, techno-science education activities can be applied. Techno-science provides an understanding of physical and chemical regularity phenomena and gives the ability to create a phenomenon and devise ways to control, manipulate, and engineer it.
In this study, the topic of Dye-Sensitized Solar Cells (DSSCs) was chosen as a technochemical model. Solar cells of DSSCs type can be engineered using organic dyes extracted from plants to mimic certain plants and algae's processes, converting sunlight into energy like photosynthesis processes. Although DSSCs are still in the early relative stages of development, it can promote solutions for obtaining electrical energy at low cost and relatively quick manufactured, compared to other electrical energy recovery alternatives such as cheap silicon solar cells. DSSC is also an attractive candidate as a new renewable energy source.
There are previous researches related to learning DSSCs. The first research was conducted by Chien et al. (2018). It is oriented towards learning DSSCs through laboratory work to provide visualization of changes in light energy into electrical energy and understand the working principles of solar cells add to the concept of plant use. The second study about DSSCs learning was discussed by Smith et al. (2013), it is oriented towards solar energy demonstrations using environmentally friendly household materials to demonstrate the ease of technology that is easy for learners to understand. The third, the DSSCs learning research, was exercised by Enciso et al. (2018); this relates to the applicative learning of basic chemistry through open-source microcontrollers and solar cells as a switch that depends on room lighting conditions. All the complete research above has not been implemented in the classroom and its relation to VNoST (View of Nature of Science and Technology). Also, the students of the chemistry department who become chemistry teacher candidates have not been studied. The present research is conducted to produce a didactical design based on a techno-chemical learning framework that has proven the strengths and weaknesses of VNoST that are completely done by experimental studies. The didactical design here means a lesson plan designed to solve and direct students in order to create an entirety comprehending, not only limited to one context.

RESEARCH METHOD
Design of research used in this study is the Model of Educational Reconstruction (MER). According to Duit et al. (2012) and Niebert & Gropengiesser (2013), MER is a model with a relevant research framework in science education to improve the quality of the learning process rearrange the concepts which have been presented.  (Duit et al., 2012) MER consists of three main components: clarification and concepts analysis, investigation of the learning process, and evaluation of the learning process. In the early stages, clarification and analysis of the concepts will be taught, and the learning process will be carried out. At the investigative stage, the learning process is carried out to find out the views of learners and the conception of educators during the learning process. The evaluation stage is carried out to find out the problems that occur during the learning process. The relationship of the three MER components can be seen in Figure 1. This research was conducted by involving students of the chemistry education department in one of the State Universities in Indonesia as respondents who have studied basic chemistry, inorganic chemistry, and organic chemistry. Twenty-five student respondents attended the pre-conception study (learning barriers).
Implementing the DSSCs learning didactical design was carried out in a limited experiment involving ten student respondents. The didactical design was validated by four experts in the field of chemistry and chemical education, and the results were given in an expert judgment. The instruments used in this study are shown in Table 1.

Scientific Conception of DSSCs, Related Chemical Content and The Relationship Between The Two
There are following monographs and journal articles used in the content analysis to obtain scientific conceptions of DSSCs, chemical concepts related, and both relationships.
c. Journal Article "Sub-Micrometer-Sized Graphite As a Conducting and Catalytic Counter Electrode for Dye-sensitized Solar Cells" (Veerappan et al., 2011).
Based on the text's content analysis, there were two basic texts from element-tarization: The Components of DSSCs and The Principles of DSSCs. The results of this content analysis are presented in Table 2 and Table 3.

Aspects of VNoST and Related Chemical Concepts
The DSSC structure consists of materials glued to two conductive oxides (TCO) transparent glass that acts as anode and cathode.
Anodes/electrodes are conductive glass coated with mesoporous semiconductors that are coated with organic dyes.
The cathode or electrode comparison is a conductive glass coated with inert metal.
There is an electrolyte solution among the conductive glass, usually the electrolyte pair of redox iodide/triiodide (I -/I3 -).
The components that make up the DSSCs are:

VNOST Aspects
Characteristics of science and technology, objectives of science and scientific research, characteristics of scientific knowledge and scientific theory, and relationships of science and technology.

Related Chemical Content
Aromatic compounds (electron delocalization), atomic theory of quantum mechanics, covalent bonds, London dispersion force, periodic elemental properties (semiconductors), electrolyte solutions, and ion bonds.

Aspects of VNoST and Related Chemical Concepts
The principle of solar cells can be explained by changing chemical reactions of sunlight radiation into electrical energy. The DSSC device consists of electrodes/anodes and cathode electrodes. In electrodes/anodes occur the oxidation process/occurrence of electron transfer, while in the electrodes, comparison/cathode occurs electron reception.
When sunlight radiation hits the DSSC device, photons are absorbed by color molecules (D). Photons that hit color molecules interfere with π bonds and cause their electrons to be excited from the ground state (HUMO) to the excited state (LUMO).

Aspects of VNoST and Related Chemical Concepts
Electrons in the TiO2 conduction band then move to the SnO2 conduction band on the conductive glass and towards the external trajectory, resulting in an electric current.

Student Pre-Conception of DSSCs, Related Chemical Content, and Relationship
An interview method between interviewers and students can be used to investigate mental construction and get a glimpse of various aspects of learner conception to obtain the full aspect (Holbert et al., 2015). This methodology has been successful and can widely used to test conceptual learning in science, either a formal or informal context. The results of pre-conception interviews of prospective chemistry teachers are showed in Table 4. The third category explains that from the analysis results can be interpreted all students answered the benefits obtained through the context of DSSCs based on their views after they have obtained information about the composition, working principles, tools with DSSCs application, and video creation. As for the chemical content in the DSSC itself, students can only associate 2-3 electrochemical content, redox reactions, and chemical reactions.
Analysis of student pre-conception study results is shown in Table 5.  Table 6 shows how students' scientific and pre-conception of DSSCs, related chemical concepts, and relationships are integrated to get a basic picture of their didactical design. Metal where reduction is an occurrence 7.

Scientific Conception versus Student Pre-Conception
Electrolyte solution A solution consists of perfectly dissociated/partially dissociated ions in the solvent to conduct electrical current.
Solutions that can conduct electricity Figure 2 shows the main part of developed didactical design. This didactical design has been validated with the acquisition of average CVR (Content Validity Ratio) as follows: (a Effect of Didactical Design Implementation on VNoST Students Implementation of didactical design is carried out through a limited scale test. VNoST's ability was conducted on a limited scale, testing ten students who had attended basic chemistry, organic chemistry, and inorganic chemistry. The results of student VNoST data can be seen in Table 7. Table 7 shows that students' understanding of VNoST undergoes a more accurate change of view with the use of the design of didactic learning DSSCs. Sub aspects of the overall definition of science undergo more accurate changes from naïve (N) to has merit (HM), from naïve to realist (R), and from merit to realist. This shows that although students have long studied science, understanding the nature of science has not been meaningful in the knowledge they have (Novak, 2002). Therefore, it can be concluded that learning activities in the sub-definition of science can be applied to strengthen VNoST for chemistry teachers. The reason for choosing the answer to choose a realist statement on the definition of science is. The student explained through the reason they choose one of them is "science is held after seeing the phenomenon that is then investigated and produces facts, concepts, and laws further obtained the theory." The second sub-aspect defines technology that changes views to be more accurate realists than five from ten students. Jurnal Tadris Kimiya 5, 2 (December) 2020): 131-143

Didactical Design of Dysenterized Solar Cell Learning Dyes
This is an open access article under CC-BY-SA license (https://creativecommons.org/licenses/by-sa/4.0/) Students still find difficulties to distinguish between science and technology. Student 1 still choosen the has merit statement, which is "the application of useful science to improve the quality of life." based on the reason that "technology was created to help people in doing activities / various things in life." This didactical design is facilitating enough to strengthen VNoST students but needs to be developed again. The reasons expressed by these students are accurate, but what improves the quality of human life is not just the application of science.
In addition, some have understood that technology is an instrument used in human life. However, student 7 choose the has merit option, so students choose the has merit statement. There is an option to statement various human-made objects such as devices, tools, and instruments. The student explained, "the end product of technology is an instrument that can be used in human life." The third sub-aspect is relationship between science and technology. That's has changed the view of 5 from 10 students, with a total of 7 students already on the realist view. The designed didactical design situation can already change the view to be more accurate for almost half of students. This means that this didactical design is valid to strengthen VNOST students, mainly associating science and technology in the context of DSSC learning. Students argue that "science is used to develop technology, then technology can develop science through scientific research." The fourth sub-aspect, the scientific model's nature, changes the student's view to be more accurate, namely having a realist view. A total of 7 students experienced changes in the meantime. Three others have been on a realist view, which means that all students have an accurate view of the scientific model's nature. This didactical design means that it can facilitate students to view scientific model is different from the original object. The reason students in defining the scientific model are "the model is more easily for us to understand something that we find difficulties to see the details. With the model we can used estimates." The fifth sub-aspect, the nature of scientific classification, shows that 8 from 10 students accurately view the realist. Students can classify a compound in their group. The didactical design situation and anticipation of the researchers' design have been in accordance with the expected results. The reason students define scientific classification is "many indicators are used to classify such as physical properties or chemical properties, but it is necessary to use the same standards to classify them until the results are more valid." The sixth sub-aspect, the scientific decision, shows that 8 from 10 students have to change their accurate view. It is a realist. Six students experienced a changing view to be more accurate. Students can define that scientific decisions must be tested many times until no one disputes them. The didactical design situation and anticipation of the researcher's design have been in accordance with the expected results. The reason students define scientific decisions is "a decision must prove successful if it has been tested many times until it can be called true and can be used as an indisputable theory." In the seventh sub-aspect, technology decisions showed that 6 from 10 students were inaccurate view calling realists. Students can define that technological decisions hang on to the well-off condition of a person. The didactical design situation and anticipation of the researcher's design have been in accordance with the expected results. The reason students define scientific decisions is "decisions using technology pay attention not only to the impact but also to all aspects." The eighth sub-aspect, the relationship between science and technology, shows that as many as nine from ten students are, on an

CONCLUSION
Scientific conception study shows that on the topic of Dyes-Sensitized Solar Cells (DSSCs), several important chemical concepts can be applied to the lecture of Material Chemistry, such as Galvanized cells on working principles, the theory of quantum mechanics atoms on the excitation of color substances, electromagnetic radiation in the type of electronic spectrum, periodic properties of elements in semiconductors, aromatic compounds through electron de location in color substances, electrolyte solutions through electrolytes used in DSSCs, ion bonds in ionic fluids, covalent bonds in conductive glass, London, and reduction and oxidation reactions in reactions occurring in anodes and cathodes.
Students' pre-conception study through interviews shows that students still have different views with scientific conceptions, especially on related chemical content such as redox reactions, galvanized cell principles, semiconductors, and electron excitation in organic color substances.
Implementation studies show that didactical design has a significant effect, especially for sub-aspects of the definition of science and the nature of scientific models, by reinforcing the change of view in the realist category. Meanwhile, it is good enough for the subdefinition of technology and the nature of technology decisions.