Environmentally-Friendly Solar Cells Inspired by Photosynthesis

Innovation: Industry

Dye-Sensitized Solar Cells

Image: natsuki / Unsplash / CC BY SA - Creative Commons Attribution + ShareAlike

Capture, Absorb, or Filter Energy

Energy is naturally available in many forms, including kinetic, potential, thermal, elastic, radiant, chemical, and more. All living systems require energy to carry out their many activities, and have developed strategies appropriate to one or more of those forms. For example, some plants maximize their surface area available for capturing radiant energy from the sun while others have strategies to focus scattered light onto photosynthesizing areas.

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Transform Radiant Energy (Light)

The sun is the ultimate source of energy for many living systems. The sun emits radiant energy, which is carried by light and other electromagnetic radiation as streams of photons. When radiant energy reaches a living system, two events can happen. The radiant energy can convert to heat, or living systems can convert it to chemical energy. The latter conversion is not simple, but is a multi-step process starting when living systems such as algae, some bacteria, and plants capture photons. For example, a potato plant captures photons then converts the light energy into chemical energy through photosynthesis, storing the chemical energy underground as carbohydrates. The carbohydrates in turn feed other living systems.

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Dye-Sensitized Solar Energy

Bring biomimicry into chemistry class with this nature-inspired lab activity in which students build a working solar cell inspired by leaves. Available in English and Spanish.

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Dye-Sensitized Solar Cells use non-toxic materials to convert light to electricity.

Benefits

Reduced costs
Non-toxic
Reduced energy usage

Applications

Industrial and residential energy generation

UN Sustainable Development Goals Addressed

Goal 7: Affordable & Clean Energy

The Challenge

Although solar energy is a progressive, sustainable approach to energy generation, the production of solar panels can generate toxic byproducts such as silicon tetrachloride, nanoparticles, and hexafluoride. These toxins can be very dangerous to human health. Additionally, in the manufacturing of most solar cells, silica (SiO2) must be heavily heated to separate the silicon from oxygen, which is an energy-intensive process.

Innovation Details

Dye-Sensitized Solar Cells (DSSCs) contain a porous layer of titanium dioxide nanoparticles covered in a dye that absorbs incoming photons from the sun, similar to the way plants absorb light for . The excited electrons in the dye are then collected for powering a load. An electrolyte solution replaces lost electrons back to the absorbent dye so the cycle can continue. DSSCs are generally considered much more environmentally benign to produce than conventional solar cells because they use relatively non-toxic materials that require little energy to manufacture. They are also able to produce the same amount of energy as a silicon-based solar cell while reducing their life-cycle environmental impact.

Simplified setup of a dye solar cell. Photo: GAMRY Instruments.

Biological Model

Photosynthesis is essential for life on Earth. It is the process by which plants produce energy and oxygen using just sunlight, water, and carbon dioxide.