EIC Accelerator Report Card: ETC Solar's Invisible Solar Contacts

ETC Solar set out to fix a small but stubborn loss in almost every solar panel: the silver lines on the front of a cell that block about 5% of the incoming light. Its answer was a printed contact shaped like a tiny triangular ridge that bounces light sideways onto the active surface instead of shading it. In the European Commission's 5 June 2019 round of the EIC SME Instrument Phase 2, the forerunner of today's EIC Accelerator, the company won a grant for ETC Solarshade, a €2,903,347.50 project with an EU contribution of €2,032,343.25, according to CORDIS. The Commission's winner list for that cut-off names ETC Solar B.V. of Enschede as the only company on the project.

The project ran from 1 October 2019 to 30 September 2021 and closed on schedule. By then the company had moved to Rotterdam, renamed its technology Mesoline, shifted its focus from solar cells to sensors and other semiconductor devices, and been bought outright by the Dutch listed engineering group Aalberts N.V. in July 2021, according to the final CORDIS report and Aalberts' 2021 annual report.

Where the Company Stands Now

The company still exists, under a new name and a new owner. The Dutch register lists Mesoline B.V. under KvK number 72152729 as active, according to OpenCorporates, and North Data links the same number to the ETC Solarshade grant and to a "MESOLINE" word mark filed on 31 May 2022. The two sources disagree on the address: OpenCorporates gives Sevillaweg 140 in Rotterdam, the site the company names on its website, while North Data gives De Hoefse Weg 2 in Vessem. The old domain etc-solar.com now redirects to mesoline.com. The exact date of the name change could not be verified.

Aalberts' 2021 annual report lists "Mesoline" among the three companies it bought that year, "as of July 2021", and says it "acquired 100% of the shares of Mesoline Inc, based in the Netherlands", adding that the business "strengthens the technology portfolio of Aalberts advanced mechatronics and does not yet generate any revenue". The report does not give a separate price. The "Inc" label sits oddly with a Dutch B.V.; the company's own website describes a "100% acquisition by Aalberts N.V. (AMS: AALB) as financial investor" in 2021, and co-founder Thomas Russell's speaker biography for an IEEE chapter talk in October 2024 says he "succesfully sold Mesoline to Aalberts N.V." in 2021. Mesoline is not named in Aalberts' annual reports for 2022 to 2025, including the 2025 report, which lists other divestments but none of Mesoline. Because the company is a group subsidiary, no separate revenue, profit or staff figures could be found.

The most recent public activity found for this article is a talk by Russell, titled "Microchannel particle deposition for MEMS & Sensors Applications", at the industry group ISIG's MEMS & Sensors World Summit EU 2025. The same IEEE biography says Russell is working on "market entry of Mesoline with the MPD technology in 2025 for several MEMS, senors and packaging markets". No customer, order or product launch from that market entry has been announced.

The Technology: From Solar Contacts to a Wafer Printing Process

The idea came from Harry Atwater's photonics lab at Caltech. The US patent on "Fabrication processes for effectively transparent contacts", granted on 30 June 2020 with a priority date of 17 August 2017, names Rebecca Saive, Harry Atwater, Thomas Russell and two other researchers as inventors and the California Institute of Technology as assignee, according to Google Patents. Whether and on what terms the company licensed it is not public. The team won a $50,000 US Department of Energy regional grand prize in a cleantech business plan competition in May 2018, according to the Atwater group. ETC Solar B.V. was formed in the Netherlands as a subsidiary of the US ETC Solar LLC, with Saive, then an assistant professor at the University of Twente, as a co-founder, according to Global University Venturing.

Ordinary solar cells carry flat, screen-printed silver fingers that shade part of the cell. ETC Solar's contacts were tall, narrow triangles that redirect light hitting them onto the cell, which the CORDIS objective says gives "optical transparency of 99.9%" and "boost solar cell power output by 5%". Those figures are the company's own; no independent test of a commercial cell with the contacts was found. In an August 2019 interview with SoCalTech, Russell said the company was raising a seed round of $1.1 million to $1.4 million, was "finalizing our first two sales contracts with two of the big players in the solar cell field" and aimed for a product by mid-2020.

The process behind the contacts became the product. Mesoline now calls it microchannel particle deposition (MPD): a polymer stamp with microchannels is pressed onto a wafer, filled with a nanoparticle ink, cured in place and peeled off, leaving structures of 1 to 50 microns with aspect ratios up to 5, according to the IEEE talk abstract and the company's website. It pitches MPD as more accurate than screen printing and more scalable than inkjet, for gas sensor electrodes, glass frit bonding rims for chip packaging and getters. Solar cells are no longer named among its applications.

What the EIC Project Promised, and What the Record Shows

The proposal was specific. ETC Solar would "commercially launch ETCs in our beachhead market, III-V solar cells", the expensive high-efficiency cells used in satellites, aerospace and cars, and "sell the ETC printing tool directly to solar cell manufacturers". It claimed "two conditional orders, four ongoing customer pilot tests and 19 potential customers", and sized the serviceable market at €235 million plus €36 million a year in consumables, according to the CORDIS objective.

The final periodic report describes a different outcome. In the first year the team closed its Enschede offices, moved to Rotterdam and built an "ETC Direct Printing Machine Prototype" for 4-inch (100 mm) wafers; in the second year it scaled the tool to 8-inch (200 mm) wafers, signed a lease for its own production site at Sevillaweg 140 and developed "several superior (prototype) semiconductor products", among them "an ultra-low power, ultra-sensitive gas sensor". The report says "first substantial commercial interest has been received" and that "as a next step the company will start bringing the novel semiconductor products to market". It does not report a solar product launch, a tool sale or the conversion of the two conditional orders. The company's own site gives 2019 as the year of the move to Rotterdam; the report places it in the project's first phase, which began in October 2019.

1. Printing tool from prototype to production scaleDelivered4-inch prototype, then 8-inch wafers, per the CORDIS report.
2. Production facilityDelivered1,400 m2 site with an ISO-7 cleanroom in Rotterdam, per Mesoline.
3. Commercial launch in III-V solar cellsNot achievedNo solar product or customer announced; solar dropped as a market.
4. Tool sales to solar cell makersNot achievedNo sale reported; Mesoline now sells MPD as a contract service.
5. Two conditional orders convertedUnverifiedNeither the orders nor the buyers were ever named.
6. Project closed on scheduleDeliveredEnded 30 September 2021 with a published final report.

CORDIS lists no other EU project for the company. ETC Solar was not on the EIC Fund's list of invested companies under either name when all 16 pages were checked for this article; the 2019 SME Instrument Phase 2 was a grant-only scheme.

After the Grant: A Plant, a Pivot and a Corporate Owner

The Aalberts takeover gave the company a deep-pocketed parent at the moment the EU money ran out; the CORDIS report says the buyer "will finance the further scale-up and roll-out" of the technology. The Rotterdam site that followed is described on Mesoline's facilities page as a 1,400 m2 plant with an ISO-7 cleanroom, metrology equipment and an annual capacity of "around 20.000 wafers", with an ISO 9001 certified MPD process. Those figures come from the company and could not be checked against a second source.

Progress since then has been slower than the 2019 pitch. Mesoline's own news page says the team handed "the first MPD printed wafer" to Aalberts' then chief executive Wim Pelsma during a visit on 7 June 2023, almost two years after the project ended. Through 2023 the company presented at sensor and MEMS events in Nuremberg, Porto, Taipei and Grenoble, and Russell's 2022 talk at SEMI's MEMS and Sensors Technical Congress is online. The website's news stops in September 2023 and its footer still reads 2024. Aalberts' 2025 report cites "lower volumes in semicon" for the group but does not mention Mesoline.

Why It Matters for Europe

The project sat at the junction of two EU priorities. The EU's solar energy strategy targets at least 600 GW of solar photovoltaic capacity by 2030 and aims to keep more of the value chain in Europe, where cell and module making is dominated by imports; a contact that lifts cell output without extra silicon fits that goal. The European Chips Act, in force since 21 September 2023, backs semiconductor manufacturing capacity in Europe, which is where Mesoline now places itself. The grant helped keep a US-born process in a Dutch cleanroom under a Dutch industrial owner. It did not produce the European solar product it was written for.

The Verdict

Mesoline, Aalberts and the EIC were not asked for comment for this article. It is based on public records and published statements, linked throughout.