Dye-sensitized solar cells are a next-generation technology for generating electricity from sunlight that is flexible, adaptable to a variety of surfaces, affordable, and environmentally friendly. This technology has the potential to revolutionize clothing, building materials, and more.

Current energy challenges and alternatives

Currently, we rely on fossil fuels and nuclear power for most of our energy. Fossil fuels are a finite resource and their use causes environmental problems such as global warming. Nuclear power is highly efficient as an energy source, but it can cause catastrophic damage in the event of an accident, and radioactive waste disposal is a serious problem. These issues have greatly emphasized the need for sustainable energy sources. Among renewable energy sources, solar energy is gaining attention as a future energy source because it is inexhaustible, clean, and has a low environmental impact.

Dye-sensitized solar cells and the future of life

“Ding, ding, ding, ding, ding!” the alarm clock rang. I opened my heavy eyelids and looked at the clock: 8:00 am. “I’m late for school!” I thought to myself as I jumped up and started getting ready for school. After quickly getting ready, I checked my phone and realized that I had very little battery left. Fortunately, I plugged my phone into my coat, which had a dye-sensitized solar cell attached to it, and it started charging. I was relieved to see that despite the cloudy weather, I could charge my phone in low light. When I arrived at school, my phone was already fully charged. A great start to the day.
This hypothetical scenario shows the future of dye-sensitized solar cells in real life. With these solar cells, we can easily charge our electronic devices anywhere and use energy in an environmentally friendly way.

History and development of solar cells

The history of solar cells began in 1839, when French scientist Becquerel discovered that metal electrodes immersed in an electrolyte increased their current when exposed to light. The first solar cell was developed in the United States in 1954 and is known as the first generation solar cell. First-generation solar cells are made of crystalline silicon and currently account for about 80% of the global solar cell market. However, this technology is expensive, has a limited range of light absorption, and is only about 18% efficient at generating electricity.
Second-generation solar cells are thin-film solar cells, which are divided into silicon and compound. This generation has a lower manufacturing cost than the first generation and can be made thinner, so it has a wide range of applications, but it still has the limitation of low power generation efficiency. The third generation of solar cells has improved on these shortcomings, offering a wider range of light that can be absorbed, higher power generation efficiency, and lower production costs. Dye-sensitized solar cells belong to this third generation of solar cells.

How dye-sensitized solar cells work

Dye-sensitized solar cells (DSSCs) mimic the natural process of photosynthesis to convert sunlight into electricity. Just as plants use chlorophyll to absorb light, these solar cells use nanoscale dye molecules to absorb light. The dye absorbs mostly visible light, which makes up about 40% of sunlight, and releases electrons, which are transferred to an external circuit via electrodes to generate electricity. This process allows dye-sensitized solar cells to generate electricity even in low light conditions, making them efficient indoors or on cloudy days.
The basic structure of a dye-sensitized solar cell is a “sandwich structure”. A thin glass substrate is coated with nanoparticles of titanium dioxide (TiO2) and a dye is bonded to it. The electrodes are filled with an electrolyte that promotes oxidation/reduction reactions. When light absorbs the dye, electrons are released, which travel through the TiO2 to the electrodes, where they provide electrical energy via an external circuit.

Advantages of dye-sensitized solar cells

Dye-sensitized solar cells have a number of advantages. For one, they are flexible and can be applied to a variety of surfaces, including clothing and building windows. Unlike conventional silicon solar cells, they are translucent, so they can be used as a building material. It is also insensitive to changes in the angle of incidence of light, allowing it to operate stably in various environments. They are highly efficient even in weak or scattered light, and they are also highly aesthetically pleasing as they can be produced in a variety of colors.
In addition, dye-sensitized solar cells are much cheaper to produce than conventional solar cells because they use low-cost, resource-abundant materials, primarily TiO2. This makes them economically attractive and, thanks to their environmentally friendly manufacturing process, they also emit less carbon dioxide. Thanks to these advantages, dye-sensitized solar cells have the potential to be used in a variety of applications, including windows, cars, and clothing.

Challenges to overcome

However, dye-sensitized solar cells still have some challenges to overcome. The main one is that their power generation efficiency is lower than that of conventional silicon solar cells. Currently, dye-sensitized solar cells have an efficiency of 11-12%, compared to 18% for silicon solar cells. Another issue is the leakage of electrolyte. The electrolyte in dye-sensitized solar cells is liquid, which can evaporate or leak during long-term use. To solve this problem, solid-state electrolytes are being actively researched.
Recently, Professor Michael Grätzel’s team in Switzerland has developed a dye-sensitized solar cell using a solid polymer electrolyte to solve this problem. Further advances in this research will bring dye-sensitized solar cells closer to commercialization.

Commercialization and future prospects

Dye-sensitized solar cells are already under active research for commercialization in many countries. In particular, efforts to commercialize them are underway in Europe, Japan, and the United States with national support, and in Korea, a project to utilize dye-sensitized solar windows as building materials is being promoted with the support of Daedeok Special Economic Zone. Once these technologies are commercialized, solar cells will be more widely used in our daily lives and we will be able to maximize the efficiency of energy use.
Recently, bags with dye-sensitized solar cells have been attracting attention. These bags can charge electronic devices indoors and outdoors using solar cells as thin as 1 millimeter or less. In the future, this technology will be applied to various fields such as clothing, electronics, and architecture, greatly changing the way we live.
Dye-sensitized solar cells have great potential as a future energy source. Not only are they low-cost and environmentally friendly, but their flexibility and transparency make them promising for a variety of applications. With continued research and improvement, dye-sensitized solar cells will be commercialized, and we can look forward to a future where solar energy is freely available anytime, anywhere.