Tag: Solar Cells

Inserting a layer of meal fluoride can improve performance of solar cells, explain researches

According to a finding from KAUST researchers, adding a metal fluoride layer in multi-layered perovskite-silicon solar cells can delay charge recombination and improve performance.

Pair of solar cells that bind perovskite and silicon-based subcells in one gadget is likely to better harness and convert solar energy into electricity than their traditional single-junction silicon analogs at a lower cost.

However, the striking of sunlight of perovskite subcell leads the resulting pairs of elecrons and positively charged holes to tend to recombine at the interface between the electron-transport layer and perovskite.

Additionally, a difference between energy levels at the interface obstructs electron separation within the cell. This cumulatively lowers the maximum operating voltage that is available, or open-circuit voltage of the pair of cells and limits device performance.

Importantly, the performance issues can partially be solved. This involves introducing a lithium fluoride layer between electron-transport and the perovskite layer, which usually contains the electron-acceptor fullerene. On the downside, lithium salts liquefy readily and pass through surfaces, which make the devices unstable.

Meanwhile, all of these devices remain untested for the standard test protocols of the International Electrotechnical Commission, and thereby prompt to create an alternative, stated the lead author of the study.

The team of researchers systematically examined the possibility of other metal fluorides such as magnesium fluoride. This involved thermal evaporation of metal fluorides on the perovskite  to create an thin uniform film with controlled thickness before including C60 and top contact constituents.

In fact, the interlayers are also highly stable and transparent to match inverted p-i-n solar cell specifications.

The magnesium fluoride interlayer effectively enabled electron extraction from the perovskite active layer while shifting C60 from the perovskite surface.

Researchers create extremely transparent solar cell employing 2D atomic sheet

Solar panels often receive flak for spoiling the appearances of homes and businesses. This may be about to change.

In a new development, a research group has created an extremely transparent solar cell with a 2D atomic sheet. These nearly invisible solar cell attained an average visible transparency of 79%, which implies, theoretically, they can be placed everywhere for building windows, front panel of cars, and even human skin.

In fact, scientists have long sought to fabricate transparent solar cells, but suitable materials have not existed so far.

To fabricate the solar cell, it involved controlling the contact obstructions between indium tin oxide – one of the most extensively used transparent conducting oxides, and a single layer tungsten disulphide. Various thin metals were coated on indium tin oxide and a thin layer of tungsten oxide pushed between the coated indium tin oxide and tungsten disulphide.

The way in which the solar cells is fabricated resulted in a power conversion efficiency more than 1,000 times that of a device that uses a normal indium tin oxide electrode.

The effort of the group did not stop here. They also explored how solar cell can be expanded for use in an actual solar panel.

The appropriate design modifications needed to avoid an unexpected drop in voltage that follows with the increase in device area was discovered, stated one of the researchers.

The details of the research is published in the journal Scientific Reports.

Researchers devise strategy for over 25% efficiency of amorphous silicon solar cells

Over the recent past, engineers worldwide have been developing various new technologies for generation and storage of energy more sustainably. Solar or photovoltaic cells, electrical devices that can convert light from sun into electricity are some of these technologies that are developed.

Perovskite/SHJ tandem solar cells and silicon heterojunction solar cells are two promising types of solar cells that are developed for sustainable energy. These classes of solar cells are created using hydrogenated amorphous silicon – the non-crystalline form of silicon which is also commonly used to construct thin-film transistors, LCD displays, and batteries.

In fact, hydrogenated amorphous silicon has been used for numerous years to create photovoltaics. This is due to its tunable conduction, low defect density, and other advantages. Nonetheless, since advantages of the material relies heavily on configurations of hydrogen and silicon in 3D space, this requires engineers to be able to control its microscopic configuration with high levels of accuracy to create highly fulfilling devices.

Earlier, to use hydrogenated amorphous silicon, material scientists have tried to dope it using the metalloid chemical substance boron to obtain light from the sun more effectively. However, so far, most scientists attained poor and unreliable results.

In a new attempt, researchers at King Abdullah University of Science and Technology, Zhongwei New Energy, and Chinese Academy of Sciences recently introduced a new strategy that involved doping hydrogenated amorphous silicon using boron to improve its efficiency significantly.

The strategy published in Nature Energy essentially requires light soaking the films.

Meanwhile, the extremely small doping capability of trivalent boron in amorphous tetravalent silicon limits light harvesting of SHJ by their fill factors, which is a direct unit of the charge carrier transport.

Researchers devise New Method to Improve Efficiency of Perovskite Solar Cells

Perovskites have emerged as the leading material that can in the due course replace silicon for solar panels. Perovskite offers the potential to manufacture low-cost, ultrathin, lightweight flexible cells at low-temperatures. However, so far, the efficiency of perovskites to convert sunlight into electricity has lagged that of silicon and other alternatives.

Meanwhile, a new approach to design perovskite cells has helped to match, or rather exceed the efficiency of typical silicon cells. In the first phase, the efficiency of perovskite cells is from 20 to 22 percent, which forms the basis for further improvements.

In the new design, researchers added a specially treated conducting tin dioxide layer to perovskite material. This arrangement provides an improved path for charge carriers in the cell, and by altering the perovskite formula, the overall efficiency of perovskite as solar cells increased to 25.2 percent. This is a near record for such materials to surpass the efficiency of several such currently used solar panels. Nonetheless, perovskite still falls behind silicon significantly in terms of longevity – a challenge undertaken by teams worldwide.

The findings of the research is published in a paper in the journal Nature.

In terms of classification, perovskites are a broad group of materials characteristic of a particular kind of lattice. Interestingly, there is a huge number of possible chemical combinations to make perovskites. And, these materials can attracted interest of material scientists across the world, and these materials can be manufactured cheaply than gallium arsenide or silicon, at least on paper, explained one of the research associates. The interest in perovskite materials, in part is because of its much simpler processing and manufacturing operations.