Dye-sensitized solar cells are a technology that uses dyes to absorb sunlight and convert it into electricity, with the advantages of low cost, a wide range of colors, and the ability to operate in low light levels. This technology has potential applications in various fields such as architecture, agriculture, and environmental protection, and commercial success is expected to be achieved by reducing research and production costs.
The last thing anyone wants to do on a sunny spring day is work hard at the office while listening to their boss nagging them. We’d all love to be out in the sunshine, wearing colorful clothes, and enjoying the spring in the sky. But alas, we have to work to earn money, and we need it to live. What if you could make money while having a fun spring break? You could get dressed up, have fun walking around the Han River, and call your boss and tell them you’re out of town. You might think this sounds crazy, but there is a technology that can make it happen. It’s called dye-sensitized solar cell technology. As the name suggests, this technology uses dyes to absorb light energy from the sun and convert it into electrical energy.
Dye-sensitized solar cells are primarily seen as a green energy solution. Compared to conventional solar cells, dye-sensitized solar cells can be produced at a relatively low cost and can be made in a variety of colors and transparencies, which is advantageous for the exterior design of buildings. They also have the advantage of being able to operate in low light levels, making them efficient in indoor environments. These advantages make dye-sensitized solar cells a sustainable future energy technology.
The dye-sensitized solar cell can be thought of as a three-part structure. The three parts are the part that receives the light, the part where electrons are transferred and energy is produced, and the part that returns the transferred electrons to the original state so that the cell can continue to work. Let’s look at the flow of light energy from the sun. First, sunlight is directed toward the dye molecules in the solar cell. When the dye molecules absorb the light energy from the sun, the electrons in the dye molecules absorb it and become highly energized, or “excited”. These excited electrons then travel through the circuitry of the solar cell, producing electrical energy. The excited electrons then travel to the metal oxide that is attached to the dye molecule. This collection of dye molecules and metal oxides is called the light absorber. Since this is an important part of the process that directly receives light, it has several characteristics. First of all, different materials have different energy absorption capacities, so we need to use dyes with unique energy bands that can absorb solar energy well. You’ll also need to increase the surface area of the metal oxide covered by the dye molecules to receive more sunlight. This is why we use a structure with many microscopically small grains rather than a flat surface.
Now let’s follow the energy flow again. The excited electrons transferred to the metal oxide above are directed to an electrode that is adjacent to the metal oxide. You can think of these electrodes as the + and – sides of a cell, similar to the ones we see in a regular cell. The electrons that make it to the working electrode travel through a circuit that is connected to the outside of the electrode and travel along the circuit to the counter electrode on the other side of the cell. As it travels through this circuit, it creates a potential difference between the two electrodes and reduces the energy of the electron by the amount of work it has done, creating electrical energy equal to that reduced energy. You can think of this as being similar to the cells you see around you that have a potential difference of a few volts across the ends. Since these electrodes are also involved in the movement of electrons, they can be made of what we would normally think of as highly electrically conductive materials, namely metals.
Now, the final step. When the electrons finally arrive at the other electrode, the dye molecule will need to be supplied with electrons again. To do this, there is an electrolyte layer between the counter electrode and the metal oxide. This electrolyte layer supplies electrons to the dye molecules to fill the vacancies left by the electrons of the dye molecules that have traveled away. In the electrolyte layer, the electrons that are negatively charged become unoccupied and are paired with virtual + particles, called holes, in the electrolyte layer. It’s convenient to think of it as the electron with the – charge escaping, leaving the + charge behind. The hole combines with an electron that has reached the other electrode and returns to its original position, i.e., neutral. The electrolyte layer that is suitable for this process is usually iodine, a substance that makes it easy for electrons and holes to move and combine. This sequence of events allows for the continuous production of electrical energy, provided that light energy is continuously supplied.
Dye-sensitized solar cells are not yet efficient enough to be useful in real life. The efficiency of the light received and the electricity produced is not high enough. However, what makes this dye-sensitized solar cell stand out from other solar cells is that it uses dyes to absorb light, which means that the cell itself takes on the color of the dye, so if it is used in the construction of buildings and other structures, it will be a breakthrough technology that can generate solar power while beautifying the exterior. This technology will be useful as human society evolves, and as more and more structures cover the ground. Also, if the electrode part mentioned above is not made of metal, but of a special plastic material that is flexible and capable of electron transfer, it will be possible to embed the cells in the colorful clothes we wear, as mentioned at the beginning of this article. In other words, even when we are enjoying a leisurely stroll, the electrons in our clothes will continue to travel and generate energy.
Advances in dye-sensitized solar cell technology open up new possibilities for many people. For example, this technology can be of great help in the agricultural sector. By installing dye-sensitized solar cells in a greenhouse for growing crops, you can not only efficiently utilize sunlight to power the inside of the greenhouse, but also keep the greenhouse looking beautiful. This technology can also play an important role in protecting the environment. It can help reduce the use of fossil fuels and contribute to solving the problem of global warming through clean energy. With such vast application possibilities, dye-sensitized solar cell technology has every reason to be researched.
Finally, the commercial success of dye-sensitized solar cells requires not only research to increase their efficiency, but also efforts to lower their production costs. Currently, many researchers are experimenting with different dyes and materials to increase efficiency, and these efforts are gradually bearing fruit. Hopefully, dye-sensitized solar cells will become more widespread and become an important source of energy in our daily lives.
