Transparent conductive zinc oxide for touchscreens and solar panels

DTU team got very close to winning EU cleantech final with new material for touchscreens

Monday 03 Nov 14


Dennis Valbjørn Christensen
DTU Energy
+45 20 96 19 46


CleanLaunchpad ( is Europe’s largest cleantech business idea competition. This year hundreds of business ideas were submitted from 11 participating countries, varying from Poland, Cyprus to Denmark, and after an intensive six months tour of boot camps, coaching sessions and national finals, thirty of Europe’s best cleantech ideas were taken to stage in the morning of 29th of October in Valencia, Spain. Here they were cross-examined by 30 of Europes leading investors and entrepreneurs in 5 parallel sessions.

Two young researchers from DTU Energy Conversion, Li Han and Dennis Valbjørn Christensen, won the Danish finals and got close to winning the EU finals of CleanLaunchpad, Europe’s greatest cleantech business idea competition. They received excellent feedbacks on their material, which may be able to substitute the widely used but expensive indium tin oxide (ITO) in touchscreens and solar panels – it has the same excellent properties, just 150 times cheaper.

Two young researchers from DTU Energy Conversion at the Technical University of Denmark (DTU) have found an inexpensive material that is transparent and at the same time an excellent electrical conductor. Such transparent conductors are an essential part of touchscreens and solar panels. The new material is 150 times cheaper than the currently used indium tin oxide (ITO) and has a very great potential.

With a business idea based on the material postdoc Li Han and PhD-student Dennis Valbjørn Christensen first won the Danish finals and then got close to winning the European finals of CleanLaunchpad, Europe’s greatest cleantech business idea competition.

"I had the knowledge of the materials, while Dennis knew about thin films and helped improve it"
Li Han, post doc at DTU Energy Conversion

“In my opinion, you guys have the most promising technology of all the pitches I have heard here, and you should really go for it – it should be straightforward for you to do this”, said one of the jurors.

The only thing standing between the Danish team and victory was a missing description of climate impact.

Excellent feedback

“We knew before heading to Valencia, that we lacked a proper quantification of the climate impact. We, that is mostly Li Han, had worked a lot on getting the numbers and given just a bit more time we might have had a proper business case with either thermally insulating windows or solar cells”, says Dennis Valbjørn Christensen and continues: “If we had had a solid business case with a strong climate impact, I find it very realistic, that we would have been in top-2.”

The jurors and organizers of the CleanLaunchPad-competetion agreed and gave excellent feedback.

 “Everything was really great except the part with the climate impact. The pitch was impressive, the idea is great and the Q&A went very well, but unfortunately this is a climate competition and therefore we need to have quantified climate impact”, said one, trying to explain why the young researchers from DTU didn’t win outright.

“Several of the judges voted for you, but when the discussion got into more details, they could not properly justify this with a lack of climate impact”, said another.

The very positive response to Li Han and Dennis Valbjørn Christensen’s idea is a testimony to how a different perspective can make a great project become even greater.

It started with Li Han making his PhD project “High Temperature Thermoelectric Properties of ZnO Based Materials” based on years of research into finding new materials for thermal generators able to convert excess heat into electricity. Then Li Han’s good friend Dennis Valbjørn Christensen, a fellow PhD student with expert knowledge in thin films, took part in this year’s DTU Summer School on Entrepreneurship.

Rethinking idea after Summer School

“I came to the summer school with several good ideas, but the more I heard about what makes good ideas into businesses, the more I honed in on using Li Han’s materials for solar panels and touchscreens”, explains Dennis Valbjørn Christensen, who won the 1st prize at the summer school with his business idea based on Li Han’s research.

Returning home to DTU Energy Conversion, he quickly talked Li Han and his supervisor Professor Nini Pryds into rethinking Li Han’s project. And indeed it turned out that Li Han’s ZnO based materials may be able to substitute the expensive ITO in touch screens and solar panels.

Transparency and electrically conductivity are normally contradicting properties. For example, metals have good conductivity but no transparency, while glass is transparent but electrically insulating. However, the ZnO based material discovered by Li Han has both properties, which is very much in demand by the multinational companies making solar cells or tablets and smartphones. The new materials are much cheaper than ITO and can be deposited using existing techniques.

“I had the knowledge of the materials, while Dennis knew about thin films and helped improve it”, says Li Han, who has now become postdoc after finishing his exams.

First science, then business

Transforming research and good ideas into good and sound business models can be tough, so in September Li Han and Dennis Valbjørn Christensen took part in a joint Scandinavian workshop on Entrepreneurship in Gothenburg, Sweden, as preparation for CleanLaunchPad.

“It’s quite a challenge, because it’s all about making the right sales pitch to a non-science audience”, says Dennis Valbjørn Christensen. “You have the expert technical knowhow, but pitching an idea to the jury is 90 percent business and only 10 percent science. It’s all about: Can we make this into a solid business!?”

The jury and the audience of the Danish CleanLaunchPad thought so and gave Li Han and Dennis Valbjørn Christensen a 1st prize at the national final and a ticket to the CleanLaunchPad EU-finals in Valencia, Spain, where the two got close to winning the European CleanLaunchPad.

Head of DTU Energy Conversion, Professor Søren Linderoth, finds their achievement very impressive.

“I am very proud of Li Han and Dennis Valbjørn Christensen’s achievement and I find the feedback from the jury and organizers of CleanLaunchPad very encouraging for their project and their discovery in the future”, says Professor Søren Linderoth, congratulating the team and their product-idea.