In search of perfect silicon

Silicon is the go-to material for solar devices like photovoltaic panels despite its relatively low energy conversion rate of 15-22%. Researchers all over the world are analysing materials and creating new ones to find a better solution. A lucky handful are armed with a laser scattering tomograph (LST), the best instrument for the task.

An LST illuminates the sample material with an infrared laser beam, which scatters wherever it finds a defect. If there is a defect in a material’s structure, even one just a few nanometers wide, the very sensitive CCD camera at the other end of the machine will pick it up, allowing researchers to learn and adapt. It also boasts a robotic system that allows it to automatically load multiple samples at once.

The LST is very rare, but fortunately, one has found a home at the University of Malta’s (UM) Institute for Sustainable Energy (ISE), a brand new, state-of-the-art facility aimed towards finding efficient solutions for harnessing solar power to its fullest extent. ‘There are probably 10 to 12 of these worldwide,’ confirms Prof. Luciano Mule’ Stagno, Director of the Lab at the ISE. ‘Ours is one of the few in the world to be found in a university, almost certainly the only one in a university in Europe. Most of these machines are in industry settings,’ he says.

This enables the UM to conduct cutting-edge research in a field that is practically nascent, putting it at the forefront. With the LST, material engineers could unlock the secrets behind the perfect variation of defect-reduced silicon. This rise in efficiency could have a substantial impact on the worldwide sustainable energy market.

Author: Prof. Luciano Mule’ Stagno

Netherlands: a land of bikes, clogs, and research


My journey started in 2006, when I started my bachelor in Mechanical Engineering (University of Malta). My passion lay in Materials Engineering, so I focused my undergraduate thesis in this area. I studied ways of improving the corrosion resistance properties of Nitinol, an alloy of Nickel and Titanium. This material is used in many biomedical applications. I built an environment similar to the human body to test the material’s corrosion properties.

After graduating in 2010, I took an M.Sc. in biomedical engineering and specialised in biomaterials (Delft University of Technology, Netherlands). Over this two-year programme as part of my technical internship, I worked at the Orthopaedics Research Department of the Erasmus Medical Centre (Rotterdam). I worked with two other Ph.D. students researching titanium scaffolds for bone defects.

Following my internship, I moved back to Delft and performed another research project again on the alloy Nitinol. We were using it to improve heart stents, tubes used to prop open blood vessels when they are clogged. I created a layer of a ceramic, porous Titanium dioxide, on the surface of Nitinol and then filled the pores with a novel drug that prevents the blockage of blood vessels. Heart stents sometimes fail by getting clogged, the slow release of the drug, which we monitored, would help prevent blockages hence heart attacks at a later date.

But my time in Delft was not yet over. I remained at TU Delft to take up a two-year research position. This time I am researching how natural polymers can be used to make artificial cartilage tissue for patients who need it replaced — a challenging project since I am learning how to set up a new lab for a new subject.


Cuschieri was awarded a STEPS scholarship for her Masters studies, which is part-financed by the EU’s European Social Fund under Operational Programme II — Cohesion Policy 2007–2013.