May 2016

A team of scientists from Israel, Singapore, and Switzerland has reported a major advance in the physics of perovskite solar cells ' by producing high-performance cells whose efficiency surprisingly improved as the cells heated up, in contrary to the usual drop in efficiency that occurs upon heating of a solar cell.

The researchers used experiments that varied the intensity of light and cell temperature, helping to better understand the molecular mechanisms that allow these solar cells to discharge high voltage while maintaining high current density and low internal resistance, which are essential for their superior performance. The study suggests deploying perovskite solar cells under concentrated sunlight in order to realize even higher efficiency'one of the next tasks in their planned experimental studies.

We are happy to announce a new Metalgrass knowledge hub, RRAM-Info.com, that focuses on RRAM, or Resistive RAM technology. RRAM is a promising next-generation storage-memory candidate, based on memristors - materials that change their resistance.

RRAM-Info will bring you daily news, commentary and updates about RRAM memory technologies. You can subscribe to our weekly RRAM newsletter here - and if you have not done so already, be sure to also subscribe to the free perovskite newsletter!

Solliance announced a 10% aperture area power conversion efficiency for its up-scaled thin-film perovskite photovoltaic modules. The efficiency was measured on an aperture area of 168 cm². Twenty-five cells were serial connected through an optimized P1, P2, P3 interconnection technology. The PV module was realized on a 6x6 inch glass substrate using industrial scale-able slot die coating in combination with laser patterning.

Based on previous optimization on 16 cm² modules, the Solliance team was able to transfer this to a 6x6 inch sized glass substrate using the developed blade coating process and the optimized mechanical patterning technology. These results demonstrate the up-scalability of this new thin film PV technology. Apart from the electrodes currently used, all layers can be processed in ambient environment and at temperatures below 120⁰C. Furthermore, the deposition and interconnection technologies used for obtaining these results are industrially available for Sheet-to-Sheet as well as for Roll-to-Roll manufacturing. The latter allows for creating high volume production in the future.

Researchers at University College London, UK, have reassessed the validity of the 'tolerance factor' (a decades-old indicator for the stability and distortion of crystal structures), used in predicting new hybrid perovskite structures. The results of their work may cast shadows on the optimism that surrounds perovskites' future uses.

Recent studies out of Cambridge University showed that the tolerance factor approach worked well at assigning radii to organic ions in a wide range of hybrid perovskites. They suggested that there could be more than 600 undiscovered hybrid perovskites. The UCL team was interested in whether the tolerance factor approach was still valid for halide perovskites suitable for solar cells. The chemical properties of the heavy iodide anions in these structures are very different to the hard atomic spheres assumed in tolerance factor calculations. The results suggested that 'the tolerance factor simply doesn't work for iodide perovskites.'

Researchers from Brown University, the National Renewable Energy Laboratory (NREL) and the Chinese Academy of Sciences' Qingdao Institute of Bioenergy and Bioprocess Technology came up with a way of "flipping a chemical switch" that converts one type of perovskite into another - a type that has better thermal stability and is a better light absorber. This achievement could be one more step toward bringing perovskite solar cells to the mass market.

The researchers demonstrated their new technique for making solar cells that can be more stable at moderate temperatures than the perovskite solar cells that are currently being developed; The technique is said to be simple and has the potential to be scaled up.