COD sensor, also called COD probe, is an instrument used to measure chemical oxygen demand in water or wastewater and supports online digital transmission. Utilizing the advanced UV254 ultraviolet absorption method, it ensures fast, accurate, and reliable organic content measurements, enabling continuous online monitoring of water quality. Beyond COD, this versatile sensor can also detect parameters such as Total Organic Carbon (TOC), Turbidity Units (TU), and Total Suspended Solids (TSS), making it suitable for applications requiring comprehensive water analysis. Its dual functionality as a COD-TSS sensor or COD-TU sensor enhances its utility in environmental protection, wastewater treatment, and industrial monitoring systems. Chemical Oxygen Demand (COD) is a key parameter for evaluating organic pollution in water. It measures the oxidant consumed during the oxidation of organic and certain inorganic materials in water. High COD levels signify excessive organic pollutants, which may deplete dissolved oxygen, adversely impacting aquatic ecosystems and water usability. Monitoring COD helps ensure compliance with environmental regulations and guides effective water treatment. COD Sensors use the UV254 ultraviolet absorption method to analyze water samples. Organic matter absorbs ultraviolet light when irradiated, and the intensity of absorption correlates with the organic content, allowing precise COD value calculations. This chemical-free method is efficient and ideal for a wide range of water samples, from drinking water to heavily polluted wastewater. COD Sensors and Probes are essential for precise and efficient water quality monitoring. With their ability to accurately measure Chemical Oxygen Demand, they play a vital role in environmental protection and industrial applications. By adopting these advanced tools, industries and researchers can better manage water resources and reduce pollution. Contact us for more information about our COD Sensors and other water quality solutions. COD Sensor,COD Probe,Chemical Oxygen Demand Sensor,Online COD Monitor,UV254 COD Measurement Suzhou Delfino Environmental Technology Co., Ltd. , https://www.daruifuno.comOverview
What is COD?
How COD Sensors Work
Key Features of COD Sensors
Applications
Conclusion
Scientists Develop the World's Thinnest Light Absorbers
Scientists from Stanford University have made a groundbreaking advancement by developing the world's thinnest and most efficient light absorber. This nanostructure is just one-thousandth the thickness of regular paper, significantly reducing material costs while boosting the efficiency of solar cells. The research was recently published in *Nano Letters*, a leading journal in nanoscience and technology (see note 1).
Stacey Bent, a professor at Stanford and a member of the research team, explained, “For many applications, it’s ideal to achieve visible light absorption using minimal material. Our findings show that an extremely thin layer of material can completely absorb all visible light wavelengths.â€
Thinner solar cells not only use fewer materials but also lower production costs. However, the challenge has always been maintaining high conversion efficiency while reducing thickness. To tackle this, the Stanford team designed ultra-thin wafers embedded with gold nanoparticles—each about 14 nanometers tall and 17 nanometers wide.
The researchers used block copolymer lithography, a technique developed by Hitachi, to create these wafers. Each square inch contains approximately 520 billion gold dots arranged in a hexagonal pattern, resembling a honeycomb structure under a microscope.
To enhance performance, the team applied a thin film coating using atomic layer deposition. This process allowed them to fine-tune the system, optimizing light absorption. As Hagglund noted, “By adjusting the coating thickness around the nano-dots, we could tune the optical properties to maximize absorption. Others had similar structures, but we achieved the best performance.â€
In their experiments, the team successfully absorbed 99% of red-orange light (600 nm wavelength) and 93% of light using the gold nanoparticles themselves. The absorber layer is just 1.6 nanometers thick—over 1,000 times thinner than current solar cell absorbers, setting a new global record.
Hagglund added, “Previous records required absorber layers three times thicker to achieve full light absorption. We’ve pushed the limits even further by optimizing our ultra-thin nano-engineered system.â€
Looking ahead, the team aims to integrate this technology into real-world solar cells. Bent, director of the Stanford Energy Conversion Efficiency Nanostructure Research Center, said, “We are working on building ultra-thin semiconductor structures that can efficiently capture sunlight. Testing these prototypes will help us determine their energy conversion efficiency.â€
In the study, different coatings—tin sulfide, zinc oxide, and aluminum oxide—were tested on various nano-dot arrays. Although these coatings don’t directly absorb light, they help transfer energy from the metal particles to the semiconductor, creating longer-lived and more mobile charge carriers.
Bent emphasized the team’s ultimate goal: “We want to develop high-performance solar cells and solar fuels by minimizing material usage. By designing systems where charge carriers are produced near their destinations, we can improve efficiency and reduce waste.â€
While gold was chosen for its chemical stability, the team is exploring cheaper alternatives like silver. Hagglund noted, “Silver is less expensive and may offer better optical performance. With such a thin system, we can eventually produce solar cells with drastically reduced thickness.â€
The research team included Mark Brongersma, Sabell Thomann, Han-Bo-Ram Lee, and Gabriel Zeltzer from Hitachi Global Storage Technologies, along with Ricardo Ruiz. Their work marks a significant step forward in sustainable and efficient solar technology.
*Editor’s note: *Nano Letters* is a prestigious publication of the American Chemical Society, focusing on cutting-edge research in nanoscience and technology.*
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