Written by: Salma El-Sakka
Researchers in India have developed a reusable, high thermal conductivity hydrogel aimed at the passive cooling of silicon solar cells, contributing to improved electrical energy conversion efficiency. The research aimed to innovate a sustainable, low-cost cooling solution to reduce operating temperatures, enhance electrical performance, and extend the lifespan of photovoltaic devices without the need for external power sources.
The gel used consists of polyvinyl alcohol mixed with carbon nanotubes coated and filled with tin. The researchers explained that tin was used due to its high wettability, low melting point, and good compatibility with carbon nanomaterials, enabling uniform coverage of the nanotube surfaces and achieving a practical balance between thermal performance, ease of manufacturing, and economic feasibility.
To prepare this gel, polyvinyl alcohol was dissolved in dimethyl sulfoxide, with the addition of tin-coated carbon nanotubes at various concentrations. The mixtures were stirred and subjected to ultrasonic waves before being cooled and poured into dedicated molds. The samples then underwent a freeze-thaw cross-linking process, alongside the preparation of a control sample of pure gel.
Scientists analyzed the gel's structure and composition, and measured its thermal conductivity, tensile strength, and thermal stability. In cooling tests, the various concentrations of the material were attached to the back of a commercial polycrystalline silicon solar cell, and their coating was compared with other uncooled devices, while monitoring weight loss and performance over multiple days, as well as testing reusability by immersing the used gel in deionized water.
The results showed that the intrinsic thermal conductivity of the tin-supported nanotubes provides superior heat transfer capability through the gel medium. The researchers confirmed that the conductive gel exhibited outstanding thermal conductivity and mechanical strength properties, highlighting its promising potential for solar cell thermal management without compromising energy conversion efficiency.
Practical tests demonstrated that the optimal concentration of the gel successfully reduced the operating temperature of the solar cell by 9.5 degrees Celsius and increased energy conversion efficiency under simulated sunlight. The gel-cooled device also maintained good efficiency after several weeks, which rose again after reactivating the gel by immersing it in water. The researchers concluded that this method offers an eco-friendly and affordable pathway to enhance solar energy efficiency, operational lifespan, and thermal management using sustainable materials, although a detailed cost assessment compared to current technologies was not provided.
