Yellow crystals are gaining popularity as alternative energy sources. They absorb sunlight and convert it into electricity through a process called the photovoltaic effect. The yellow color comes from certain impurities in the crystal structure that help optimize light absorption. Some common yellow crystals used for solar energy include cadmium telluride, copper indium gallium selenide (CIGS), and perovskites. In this article, we’ll explore what makes these crystals useful for energy and some of their key properties and applications.
Cadmium Telluride
Cadmium telluride (CdTe) is one of the leading thin-film photovoltaic technologies on the market. It consists of cadmium and tellurium bonded together to form a crystalline structure. Some key facts about CdTe:
- Bandgap of 1.45 eV, close to optimal for absorbing sunlight
- High absorption coefficient, meaning it absorbs light strongly
- Can be deposited as a thin film on substrates like glass or plastic
- Commercial modules convert sunlight to electricity at over 21% efficiency
- Relatively low production costs compared to silicon panels
CdTe’s high efficiency and low cost make it attractive for large-scale solar farms and rooftop solar installations. The crystalline film is just a few microns thick, allowing the panels to be lightweight and flexible. Some challenges for CdTe include toxicity from the cadmium and tellurium’s scarcity. But recycling methods can recover over 90% of the materials for reuse.
Copper Indium Gallium Selenide
Copper indium gallium selenide (CIGS) is another thin-film photovoltaic made from a mixture of copper, indium, gallium, and selenium elements. Here are some key details on CIGS:
- Tunable bandgap based on Ga/In ratio, optimizable for solar absorption
- High absorption coefficient like CdTe
- Can be deposited on flexible substrates
- Commercial module efficiencies over 22% demonstrated
- Potentially low manufacturing costs
The mix of elements allows the bandgap to be optimized for solar cell performance. And the flexible, thin-film construction enables lightweight panels. The main barriers for widespread CIGS adoption are installing capacity and raw material sourcing. But CIGS is a promising candidate for next-generation solar alongside CdTe.
Perovskites
Perovskites are emerging as potential breakthrough photovoltaics. They have a distinctive crystal structure with the formula ABX3. For solar cells, the A and B positions are usually occupied by organic molecules or inorganic cations like cesium, while X is a halogen atom. Here are some exciting features of perovskite photovoltaics:
- Bandgaps tunable across the visible spectrum
- Very high absorption coefficient – thin films absorb sunshine efficiently
- Can be printed into flexible thin films from solution
- Lab cell efficiencies over 25% demonstrated already
- Inexpensive raw materials and low temperature processing
Perovskites have seen rapid advances in efficiency over the past decade, surpassing older technologies. The tunable bandgap allows absorption to be optimized. And the solution printability enables low-cost, scalable manufacturing. Some challenges remain around toxicity, durability, and commercialization. But perovskites could reshape solar technology in the coming years.
Comparisons of Solar Cell Properties
Here is a table comparing some key properties of CdTe, CIGS, and Perovskite solar cells:
| Property | CdTe | CIGS | Perovskite |
|---|---|---|---|
| Best Research Efficiency | 22.1% | 23.35% | 25.5% |
| Commercial Efficiency | 21% | 22% | N/A |
| Bandgap | 1.45 eV | 1.0 – 1.7 eV | 1.2 – 2.3 eV |
| Manufacturing Costs | Low | Potentially Low | Potentially Very Low |
We can see each technology has strengths in efficiency, tunable bandgaps, and potential for low costs. Perovskites stand out with their rapid efficiency gains and tunability.
Applications of Yellow Crystals for Energy
These yellow crystals have found uses across the solar energy space:
- Rooftop solar PV – CdTe and CIGS thin films are ideal for integration into rooftop solar panels. Their lightweight, flexibility, and efficiency make them well-suited for residential and commercial rooftops.
- Solar farms – Large utility-scale solar farms often use CdTe due to its balance of efficiency and cost-effectiveness. CIGS and perovskites have potential here as manufacturing scales up.
- Off-grid uses – The lightweight nature of these technologies enables applications like powering rural villages, satellites, remote sensing, and more when off the electric grid.
- BIPV – Building-integrated photovoltaics incorporate solar generation directly into structures. CdTe, CIGS, and perovskites are amenable to BIPV windows, facades, skylights, and roofing due to thin-film flexibility.
- Transportation – Thin, lightweight yellow crystals can integrate into electric vehicles. They could extend driving range and power features while reducing vehicle weight.
Each application benefits from the high sunlight-to-electricity conversion of these crystals along with their thin, flexible form factors. We can expect their solar uses to expand as manufacturing costs decrease over time.
Future Outlook
Yellow crystals like CdTe, CIGS, and perovskites present a bright future for solar photovoltaics. Their unique properties offer advantages over traditional silicon panels:
- Thin, lightweight, and flexible constructions
- Potential for very low manufacturing costs
- High sunlight absorption and tunable bandgaps
- Continual efficiency improvements from R&D
CdTe is already a major player in large-scale solar farms while CIGS is starting to ramp up. Perovskites could disrupt the industry with projected low costs and high performance if durability challenges are overcome. Overall, these yellow crystals will help drive down the cost of solar energy, increase adoption, and facilitate new applications across society. Their unique attributes make them well-positioned to shape the next generation of photovoltaics.
Conclusion
In summary, yellow crystals like cadmium telluride, CIGS, and perovskites exhibit promising properties for solar energy generation. Their high sunlight absorption, tunable bandgaps, thin and flexible form factors, and potential for low manufacturing costs make them competitive alternatives to traditional silicon photovoltaics. Major applications include rooftop solar, solar farms, off-grid uses, transportation, and building-integrated installations. Advances in efficiency and commercialization will enable these technologies to continue disrupting the solar landscape. Yellow crystals are poised to play an integral role providing clean, renewable energy to power the planet.