INTER SPOTLIGHT: Faster, better, cheaper – materials scientists optimise solar cells


In 2008, Phillip Dale came to Luxembourg as the first ever Research Fellow of the FNR ATTRACT Programme, which aims to bring excellent young researchers to Luxembourg. It appears that the country is indeed attractive, since the native Brit chose to stay in Luxembourg even after his ATTRACT funding finished at the end of 2012.

As head of the Laboratory for Energy Materials (LEM) in the Physics and Materials Research Unit of the University of Luxembourg (UL), he is doing research on semiconductor materials and their applications in the photovoltaics industry.

In 2010, Dale established a collaboration with the University of Utah in the USA with the help of the FNR’s INTER funding instrument.

The aim of the project, dubbed “LASER” (Laser Annealing of Semiconductor Electrodeposited Reactants), was to improve the quality and production process of thin-film solar cells. The project was a complete success, Dale reports: “We were the first research group worldwide to succeed in reducing the synthesising process for the crucial semiconductors to less than one second,” Dale explains. “In terms of industrial manufacture, speed generally equates to cost savings.”

Baking with the pulsed laser

Thin-film solar cells are about 100 times thinner than conventional silicon-based solar cells. One of their advantages, among others, is that they require less semiconductor material and less energy to manufacture. For synthesising the semiconductor, the elements – usually copper, indium and selenium – are first electrodeposited onto a substrate. At high temperature, this precursor layer is then “baked” in a selenium-vapour-saturated atmosphere.

The Luxembourg scientists wanted to drastically shorten the baking time for this process, also known as annealing. To do so, they fired a laser at the semiconductor using a technique established at the University of Utah, which was made available for the UL team. In this way, they achieved a very high temperature of 800 to 900 degrees Celsius and, with it, an extreme acceleration of the reaction process.

Mike Scarpulla in Utah, an expert in the field of pulsed laser processing of semiconductor materials, and his team have meanwhile studied how structural and electronic defects can be corrected in already finished semiconductors. “That would let us considerably improve the quality of the semiconductors with relative ease,” says Dale.

More pressure, better quality

Currently, the light to electrical power conversion efficiency of the completed devices using the aforementioned laser annealed semiconductors is too low for industrial production, at about 1.5 to 2 percent. The researchers in Utah and Luxembourg are therefore planning a follow-up project, with the primary objective of investigating how that efficiency can be optimised. “We know exactly what needs to be done; we just have to perform the experiments,” says Dale. One idea the scientists have is to increase the selenium vapour pressure during annealing. Initial tests have shown that the quality of the semiconductors increases linearly as the vapour pressure is increased.

Dale relates he has learnt a lot from the project, and not only scientifically. Above all, he found the collaboration with researchers from a different culture especially rewarding: “The colleagues in the USA have an entirely different way of going about things. I found that very exciting,” Dale recounts.

This case study was originally featured in the FNR 2014 Annual Report





FNR ATTRACT Fellows: Thomas Cauvin – Public History

Public history as a new participatory model for interpreting the past: Inspired by the evolution of digital participatory sciences, the 5-year project of FNR ATTRACT Fellow Thomas Cauvin will facilitate interactions between academics, cultural institutions, and the general public to contribute to a democratisation not only of access but also of the production of history.

HistorEsch: 25 objects tell 25 local stories

A temporary exhibition at the Escher Pop-Up-Store takes a different creative approach to storytelling: „HistorEsch: Escher Geschichten a 25 Objeten erzielt” features 25 local stories, told through objects of local residents rather than images. The exhibition is part of the project of FNR ATTRACT Fellow Dr Thomas Cauvin, who works in the field of public history.

FNR ATTRACT Fellows – the people behind the science: Emma Schymanski

Emma Schymanski is a chemist and environmental engineer, who embarked on her FNR ATTRACT Fellowship in 2018. Her husband Stan Schymanski is also an FNR ATTRACT Fellow, making them the first dual career couple to both benefit from this scheme. We spoke to Emma about her group’s detective work to find traces of chemicals in our environment and the associated challenges; her experiences as a woman in STEM; open science, and the experience of setting up your own research group for the first time.

Examining cemeteries as public spaces of social inclusion, exclusion and integration

Cemeteries are multifunctional public spaces – funeral services are provided, loved ones are laid to rest – they are ‘sacred’ in the widest sense, but also frequently used as public parks – a diverse mix of people converge on these spaces of shared use. In Luxembourg City’s cemeteries conformity reigns, far from reflecting the diversity of the population. How this affects migrants and minorities is being explored as part of the international project ‘CeMi’, which examines the use and management of cemeteries as important but understudied public spaces.

A technique to perfectly screen magnetic materials

In many sciences, it is of fundamental importance to understand the internal structures of materials in detail and often to literally “shine through” them. For example, in chemistry and biology to understand crystal structures of proteins and thus their functions. Or in materials science, to understand – just one example of many – what makes magnets particularly powerful. Physicist Andreas Michels continues to develop methods that make it possible to understand material structures much better.

FNR ATTRACT Fellows – the people behind the science: Anupam Sengupta

Anupam Sengupta went from being an engineer in India to studying physics in Germany, before diving into biology in the US and Switzerland. Combining his expertise in these fields, the Indian national came to Luxembourg in 2018 with an FNR ATTRACT Fellowship to set up his research group at the University of Luxembourg as a tenure track Professor in Physics. We speak to the biophysicist about his journey and passion for uncovering the secrets of how the smallest of living organisms regulate our health and happiness, and get impacted by the changes in their environment.

Fighting autoimmunity and cancer: The nutritional key

A team of scientists at the Luxembourg Institute of Health (LIH), led by FNR ATTRACT Fellow Prof Dirk Brenner, have discovered a novel mechanism through which the immune system can control autoimmunity and cancer. The findings set a new direction for the development of future treatments of metabolic diseases. In a nod to the significance of the findings, the research graces the cover of the journal ‘Cell Metabolism’.

FNR ATTRACT Fellows – the people behind the science: Johannes Meiser

With his interdisciplinary research group, metabolism expert and analytical chemist Johannes Meiser from the Luxembourg Institute of Health (LIH) wants to uncover the role metabolism plays in the spread of cancer. We speak to the German national about his experience going from Postdoc to managing a research group; finding your niche; and the importance of a healthy work environment.

INTERnational cooperation: A virtual personal assistant for people affected by dementia

The number of people affected by dementia is steeply rising and new, innovative ways of assistive care are needed. Stëftung Hëllef Doheem (SHD) – the largest network of assistance and home care in Luxembourg – is involved in an international project that uses an innovative technology approach to assist people with cognitive problems with daily tasks, helping them live independently for longer.

This site uses cookies. By continuing to use this site, you agree to the use of cookies for analytics purposes. Find out more in our Privacy Statement