Based in Berlin, HZB, which specializes in research in areas such as solar energy, fusion power generation and battery applications, has stirred the stagnant waters of science by developing a tandem solar cell that can and does convert 32 .5% of the incident solar radiation into electricity. This is a world record for energy conversion efficiency, which was certified by the European Solar Test Installation (ESTI) in Italy, according to the university press release.
The double (or tandem: tandem approach) solar cell is essentially a photovoltaic cell made up of two layers of different photovoltaic materials (one above and one below) that are combined to absorb solar radiation and convert it into electrical energy. Helmholtz-Zentrum Berlin achieved a solar-to-electricity conversion efficiency of 32.5% using a solar cell whose base is made of silicon and whose top layer is made of perovskite (mineral oxide of calcium and titanium).
The HZB achievement has excited the research community. The scientific center – in simple words – managed to develop a photovoltaic element (cell) which can produce from a certain amount of solar radiation more electricity than any other solar cell has managed to produce in the past. This is an achievement which is expected to have particularly significant benefits (including for the charging of electric vehicles) once the new solar cells enter production. To be able to develop this particular element, the researchers had to combine the advanced perovskite composition with an interface modification that helped reduce charge carrier recombination losses.
The results of this modification were thoroughly studied and then used to design tandem solar cells that also had optical improvements. It is worth noting that in recent years, various research institutes and companies have recorded significant progress in the performance of tandem solar cells. No research program, however, had managed to achieve a solar-to-electricity conversion efficiency of 32.5%.
