Progress in solar technologies – from research to application
EU group project presents its results: high efficiencies with less material
A workshop entitled "European Solar Technology Forum – from Research to Industrial Application" took place at HZB to conclude of the European CHEETAH project on November 30, 2017. More than 100 participants from the most important European research institutes in the field of photovoltaics and from numerous universities came together with representatives from industry in order to discuss the progress achieved by CHEETAH.
Three different types of soclar cells have been greatly improved:
Silicon photovoltaics: wafer thickness cut by half
Efforts in the field of silicon photovoltaics have been directed towards the use of ever-thinner wafers in manufacturing photovoltaic modules. Several modules whose cells were 90-100 microns thick were presented at the workshop. These enable considerable savings in materials compared to standard modules with cell thicknesses of 180 microns.
Reducing material consumption in chalcopyrite solar cells by implementing an integrated lens system.
The approach to saving materials in thin-film solar cells made of chalkopyrites (Cu(In,Ga)Se2) was different: the cells were reduced in area and an integrated lens system incorporated into the module to concentrate the sunlight irradiating the cells. The goal is to achieve an efficiency level at least as high as that of current commercial modules while using considerably less material. The first prototypes already demonstrate that the method works in principle and can even reach higher efficiency levels than standard cells under certain circumstances due to the higher light intensity.
Extending the operating life of hybrid solar cells
The third topic in CHEETAH involved organic and hybrid solar cells. In this part of the project, polymer encapsulation materials were measured in an extensive series of tests and correlated with the operating life of the cells. The operating life of these solar cells could be increased to several years using the best of these polymers.
The presentations can be viewed here
- CIGS-perovskite tandem cell achieves record efficiency of 25.5 %A Berlin-based team from HZB and Center for the Science of Materials Berlin (CSMB) at the Humboldt-Universität zu Berlin has set a new record for a tandem solar cell. Using a combination of a CIGS semiconductor layer and perovskite, along with several optimised intermediate layers, they were able to convert 25.5% of sunlight into electrical energy. The previous record for this combination of materials and this size of cell stood at 24.6%. The new record has been certified and is visible in the prestigious Solar Cell Efficiency Tables (the "Green Tables"), which serve as the definitive ledger for the global photovoltaic community.
- Disorder creates new properties in compound semiconductorsAn international research team has demonstrated that the intrinsic disorder of the compound semiconductor CuInSnS₄ can be exploited to influence its optical properties. While the atomic vibrations also sense the local disorder, their response is averaged over many different local environments and therefore appear isotropic, as expected for a cubic crystal. In contrast, the optical excitations, known as excitons, are much more sensitive to the local arrangement of atoms. Surprisingly, they show a direction-dependent optical response even though the average crystal structure is cubic. These findings shed new light on the relationship between disorder and material properties, opening up new options for targeted 'disorder engineering' in optoelectronic and photocatalytic devices.
- Perovskite solar cells: Predictions of long-term stabilityReliable statements about the long-term stability of perovskite solar cells are still difficult to make. However, a new study by Dr Carolin Ulbrich’s team, published in the renowned journal Joule, highlights which methods are useful for this purpose and identifies areas where further research is needed.