This blog post explores the principles and features of dye-sensitized cells and how transparent and flexible solar technology will change the future of architecture, electronics, and more.
In the winter of 2013, a social media drama called “Infinite Power” aired on an internet video site in South Korea. The drama, which depicted the struggles and wanderings of young people in a boarding house, including job-seekers and high school students, facing a challenging reality, was characterized by the “infinite power device,” which is also the title of the drama. The drama’s character, a boarding house owner, has long dreamed of creating an ‘infinite power device’. He collects scrap metal for his dream and researches it day and night, but others laugh at him for chasing an unattainable dream. As such, ‘perpetual motion power’ was an unrealistic and impossible dream for humans. But what about a cell phone that never turns off no matter how much you use it? If it can be charged by the light from the liquid crystal when you use it, it can be said to be a step closer to the long-standing dream of infinite power. Dye-sensitized solar cells (DSSCs), which are non-silicon-based solar cells, can make this kind of life a reality.
Dye-sensitized solar cells (DSSCs) look nothing like the solar cells we usually think of. Solar cells that generate power from the sun’s light or heat can be categorized into silicon and non-silicon types, and the solar cells we know most commonly from calculators and solar streetlights are silicon solar cells. Dye-sensitized solar cells belong to the non-silicon class of solar cells. Unlike conventional solar cells, non-silicon solar cells are based on inorganic or organic materials rather than polysilicon. Because they are made of organic dyes and a glass substrate, dye-sensitized solar cells have a novel appearance, like transparent glass.
How can a simple piece of glass become a cell? The principle of dye-sensitized solar cells is based on the principle of photosynthesis in plants, and the two processes are very similar. First, electron-hole pairs (excited electrons) are generated by sunlight on n-type nanoparticle semiconductor oxide electrodes with dye molecules chemically adsorbed on their surface. This is similar to the process of electron excitation by sunlight absorbed by chlorophyll during photosynthesis. The formed electron-hole pairs are injected into the conduction band of the semiconductor oxide and transferred across the nanoparticle interfaces to the transparent conductive membrane, generating a current. This is similar to the process of photosynthesis, where electrons travel through an electron transport system to generate energy. Finally, the holes created in the dye molecules are reduced back to electrons by an oxidation-reduction electrolyte, completing the operation of the dye-sensitized solar cell. This is reminiscent of the oxidation of water in photosynthesis, where electrons are taken away and holes are filled.
Using this principle, dye-sensitized solar cells can achieve transparent color properties because they use nano-sized oxides that can transmit some of the visible light and dyes that can represent different colors. Therefore, while conventional solar cells are opaque and used on rooftops, dye-sensitized solar cells can be used on glass windows and personal mobile devices because of their transparent color characteristics. In addition, the transparency of dye-sensitized solar cells is a major advantage because they can be used on both sides. Unlike conventional solar cells, they can be installed vertically and can be oriented both east and west. This allows them to generate power before sunrise and after sunset, and they can be oriented to the east or south with equal or greater power generation.
Dye-sensitized cells also have advantages in energy conversion efficiency. Previous studies have shown that when comparing silicon-based solar cells and dye-sensitized solar cells, dye-sensitized solar cells have higher energy conversion efficiency. In terms of energy conversion efficiency as the temperature of the cell changes, there was a smaller decrease in conversion efficiency as the temperature increased. In addition, the irradiation sensitivity also showed a smaller decrease in conversion efficiency as the sensitivity decreased compared to conventional cells. The change in conversion efficiency with the angle of irradiation was also smaller than that of conventional cells, which is why dye-sensitized cells stood out in terms of efficiency.
Since the original patent for dye-sensitized solar cells (DSSCs) expired in April 2008, commercialization has been actively pursued worldwide. However, while silicon-based solar cells still dominate the market, non-silicon-based solar cells are making incremental progress in certain applications. Currently (2025), non-silicon solar cells, including DSSCs, are being utilized in building-integrated photovoltaics (BIPV), Internet of Things (IoT) devices, and wearable electronics, and products are emerging that take advantage of their flexibility and design freedom.
Experts have predicted that non-silicon solar cells will be commercially available by the mid-2020s, but large-scale market penetration has been slower than expected due to production costs and efficiency issues. However, perovskite solar cells (PSCs) are gaining traction for their high power generation efficiency and low manufacturing costs, raising the possibility of replacing conventional silicon solar cells. Recent studies have shown that perovskite-silicon tandem solar cells are nearing commercialization with higher efficiencies (over 30%) than silicon alone.
We’re getting closer to realizing the promise of cell phones that never need charging and windows that generate energy. While technological challenges remain, continued R&D and investment will allow non-silicon solar cells to expand their share of the solar market.
