June 2017

Researchers at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have demonstrated that halide perovskites are capable of discharging multiple, bright colors from just one nanowire at resolutions as small as 500 nm. This work could impact the development of new applications in optoelectronics, nanoscopic lasers, photovoltaics and more.

The team used electron beam lithography to fabricate halide perovskite nanowire heterojunctions, the junction of two types of semiconductors. The researchers analyzed cesium lead halide perovskite, and then used a common nanofabrication method integrated with anion exchange chemistry to switch out the halide ions to form cesium lead bromide, cesium lead iodide and cesium lead chloride perovskites. Each difference resulted in a different color discharged.

Researchers at Aalto University have developed a method for improving perovskite-based solar cells, that builds on previous breakthroughs improving the efficiency and longevity of such cells using printing methods (carbon back contact based perovskite solar cells or CPSCs). These findings make it possible to further enhance the efficiency of these types of solar cells.

In the new method, the perovskite solar cells were exposed to 40-degrees in a chamber where humidity was kept in the level of 70% (±5%). This kind of environment normally degrades the properties of perovskite solar cells. In this case, the treatment led to surprising growth of the perovskite crystals, which naturally absorb sunlight and generate electricity. 'The photovoltaic performance was significantly enhanced, and the overall efficiency increased almost 45%,' say the researchers.

Researchers from Spain have shown a hybrid perovskite compound that reportedly has great potential in solid-state cooling applications, due to exhibiting giant barocaloric effects near room temperature and under low pressures. Other materials are known to exhibit high caloric effects at room temperature, but many of them require high pressures and are not feasible for commercial applications.

The perovskite material was synthesized through standard wet chemical techniques. To quantify and characterize the material's caloric effects, the researchers used a combination of X-ray diffraction (XRD, Siemens D-5000 diffractomer), differential scanning calorimetry (DSC, TA Instruments Q2000) and high-pressure DSC (Setaram mDSC7 EVO). They also used a synchrotron PXRD to obtain a Rietveld analysis and calculate the entropy change.

Dyesol, the Australian company developing Perovskite Solar Cell (PSC) technology, has decided to change its name and logo to Greatcell Solar.

The decision has been reached at a general meeting of shareholders on June 9, and it expects the new name to be registered by the Australian Securities and Investments Commission around June 21, while the name and ticker change on the stock exchange should follow shortly thereafter.

A multidisciplinary team at Berkeley Lab, both from the Molecular Foundry and the Joint Center for Artificial Photosynthesis, found a possible way to dramatically boost the efficiency of methylammonium lead iodide perovskite solar cells. The team discovered a surprising characteristic of a perovskite solar cell that could be exploited for higher efficiencies, possibly up to 31%.

Using photoconductive atomic force microscopy with nanometer-scale resolution, the scientists mapped two properties on the active layer of the solar cell that relate to its photovoltaic efficiency. The maps revealed a bumpy surface composed of grains about 200 nanometers in length. Each grain has multi-angled facets. Unexpectedly, the scientists discovered a big difference in energy conversion efficiency between facets on individual grains. They found poorly performing facets adjacent to highly efficient facets, with some facets approaching the material's theoretical energy conversion limit. The scientists say these top-performing facets could hold the secret to highly efficient solar cells if the material can be synthesized so that only very efficient facets develop.

A team of researchers at the Nanyang Technological University (NTU) has demonstrated a prototype of a flexible 30cm by 30cm plastic sheet with perovskite printed on it. To achieve this, various liquid chemicals, including the perovskite, are mixed together. The solution is then poured into a standard screen printer and printed onto sheets of plastic or glass.

The team stated that since perovskite is translucent, and its color can also be adjusted through chemical processes, perovskite solar panels could even be integrated into building facades, which is not possible with current silicon-made solar panels that are opaque and would block out light. These perovskite panels could also be cheaper to produce, costing about three times less than conventional silicon cells, the researchers said.

EPFL Researchers, in collaboration with Michael Grätzel and Solaronix, have designed a low-cost and ultra-stable perovskite solar cell that has been operating at 11.2% efficiency for over a year, without loss in performance. This may represent a step towards solving the stability problem that currently poses a major obstacle towards commercialization of perovskite-based solar cell technology.

The team engineered what is known as a 2D/3D hybrid perovskite solar cell. This combines the enhanced stability of 2D perovskites with 3D forms, which efficiently absorb light across the entire visible spectrum and transport electrical charges. In this way, the scientists were able to fabricate efficient and ultra-stable solar cells, which is a crucial step for upscaling to a commercial level. The 2D/3D perovskite yields efficiencies of 12.9% (carbon-based architecture), and 14.6% (standard mesoporous solar cells).