Researchers in India have developed a reusable, thermally conductive gel that can passively cool silicon solar cells and improve their power conversion efficiency. The research aimed to develop a cost-effective and sustainable cooling solution that reduces operating temperatures, improves electrical performance, and extends the lifespan of photovoltaic devices without requiring external energy. The gel consists of polyvinyl alcohol (PVA) blended with tin (Sn)-coated and Sn-filled carbon nanotubes (Sn-CNTs).

“In the present study, Sn was employed as a coating material because of its excellent wettability, relatively low melting temperature (232 C), and good compatibility with carbon nano materials, enabling uniform coating of CNT surfaces,” the researchers explained. “Sn provides a practical balance of thermal performance, processability, interfacial compatibility, and economic feasibility, making it well-suited for enhancing the effective thermal conductivity of CNTs.”

To prepare the gel, the researchers dissolved 0.5 g of PVA in 5 ml of dimethyl sulfoxide at 120 C and added Sn-CNTs at concentrations of 0.5 wt%, 0.7 wt%, and 1.4 wt%. They stirred the mixtures for one hour and ultrasonicated them for 30 minutes before cooling and casting them into 5 cm × 5 cm molds. The samples were then kept at 0 C for 24 hours as part of a freeze-thaw crosslinking process. The team also prepared a pure PVA gel for comparison.

The scientists analyzed the gels’ structure and composition and measured their thermal conductivity, tensile strength, and thermal stability. 4 wt% formulations to the rear of a commercial polycrystalline silicon solar cell and compared their performance with that of a device cooled with pure PVA gel and an uncooled reference device.

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