HexSeed Technology, a carbon capture and utilisation (CCU) startup that transforms captured CO₂ into high-value supermaterials, has raised over €700k (£600k) in early-stage funding.
The funding was led by Carbon13, with participation from Net Zero Technology Centre and Vento Ventures. The cumulative investment also unlocks a Partnership Grant from Innovate UK, awarded on a provisional basis earlier this year.
“Data centres are on track to consume a significant share of UK grid capacity within the decade, and a large proportion of that energy is lost as heat in power conversion. This funding will allow us to take our low-temperature diamond coating technology which we are developing from laboratory demonstration to working GaN devices,” said Mark Tandy, CEO and co-founder of HexSeed.
HexSeed Technology was founded in late 2025 by Mark Tandy (CEO, Oxford MBA), Dr Leonardo Santoni (CTO, PhD in chemistry from UCL) and Dr Michael Glerum (COO, PhD in Engineering from Cambridge), and works closely with the University of Bristol.
It is developing a technology that could reduce energy waste in the data centres powering artificial intelligence. According to the company, data centres already account for a significant share of global electricity consumption, and the IEA expects that figure to reach 945 TWh by 2030 as AI-optimised facilities scale up. A large share of that power is lost as heat.
The company notes that although Gallium nitride transistors convert power far more efficiently than the silicon devices they’re replacing, they run hot, and heat is the main barrier to GaN reaching its full potential.
It further notes that diamond is the best-known thermal conductor, but growing it conventionally requires temperatures that would destroy a finished semiconductor device.
Working closely with University of Bristol Professors Paul May, an expert in diamond materials, and Martin Kuball, a specialist in semiconductor devices and heat managment, HexSeed is developing a low-carbon, low-temperature process that should allow diamond coatings to be applied directly to completed gallium nitride (GaN) devices without damaging them.
“Together with researchers from the University of Bristol, HexSeed is developing a low-temperature microwave plasma process that grows diamond coatings directly onto finished GaN devices, pulling heat away from the active regions so they run harder, last longer, and use less energy,” the startup explained.
The company plans to use this capital to demonstrate the coating process on commercial GaN power devices and progress toward pilot customer engagements, with data centre power conversion hardware as the initial target market.
Source: EU-Startups
