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.

Researchers develop sustainable alternative of currently used solar cells

Solar power is a promising alternative to conventional, non-renewable sources of energy. However, solar panels that are currently used require toxic materials as buffers, which are not sustainable. In a bid to find a sustainable alternative, a team of scientists have developed a new eco-friendly alternative called ZTO buffer. This alternative can overcome the limitation of currently used solar panels.

In fact, given the crisis related to imminent climate change, the transition to renewable energy needs to be accelerated. Meanwhile, in recent years, solar power has emerged as one of the most dependable source fewest for this task. A team of researchers at Incheon National University, Korea explain their newest contribution to this field.

Novel Solar cells cheaper, eco-friendly

Composition-wise, solar panels are made of photovoltaic cells, wherein materials that are subject to light produced excited electrons. In other words, this is electric current. Novel thin-film solar cells are made up of submicrometer or micrometer, which are thick layers of a photovoltaic material. This allows them to be integrated into lightweight, flexible panels for use in a variety of substrates. The process, however, has some limitations.

In fact, most thin-film solar cells include expensive and toxic elements, which may slow the expansion of solar cell applications. Meanwhile, the team of researchers at Incheon National University are working on the production of a solar cell made of materials that are naturally available in abundance, are eco-friendly, and are easy to obtain, and inexpensive to manufacture.

For this, the scientists considered eco-friendly cells composed of kesterite – naturally available mineral that acts as a photon absorber. Most solar cells made of kesterite use a buffer layer composed of cadmium sulfide to optimize their performance.

Research devises way to Improve Efficiency of Perovskite Solar Cells

In a new development, a team of researchers have devised a way to improve the efficiency of all perovskite solar cells using a reducing agent. The technique employed by the group and the performance of the resulting cells is described in the journal Nature Energy.

In a bid to improve the efficiency of solar panels, to make them more competitive with fossil fuels as an energy source, scientists have turned to new raw materials. Perovskite is one of the new raw materials used, a mineral that is mostly made of calcium titanate. Meanwhile, earlier research of stacking perovskite cells on silicon cells show it can increase efficiency, but does not warrants its use.

To address this, more recent research focuses on to replace silicon altogether, and stack two kinds of perovskite cells. The study of perovskite shows it can boost the efficiency of solar cells by 30 percent. Therefore, to make perovskite, engineers have been adding a metal, mostly a lead-tin mixture. However, tin oxidized during fabrication, resulting in degradation and reduced efficiencies.

New method prevents oxidation of Tin

And, with this new effort, researchers have devised a way to prevent oxidation and loss of efficiency. For the method, researchers sought to add something to tin to keep it from oxidizing. A great of search and testing revealed zwitterionic antioxidant inhibiter – commonly known as the reducing agent FSA – to find use to prevent tin from oxidizing.

In the making of lead-perovskite cells, adding zwitterionic antioxidant inhibiter prevented oxidation, and did not interfere with the operation of solar cells in other ways. Thus, without oxidation and degradation of tin, this made it feasible for the creation of all-perovskite solar cells with improved efficiency.

Research devises new color, eco-friendly thin-film Solar Cells

Around the world, research on solar cells to harness renewable energy sources is going on. In one such effort, the Electronics and Telecommunications Research Institute at South Korea has succeeded in developing eco-friendly, thin-film, and color CIGS solar cells.

CIGS thin-film solar cells find use to convert sunlight into electrical energy and are synthesized by coating multiple thin films on a glass substrate. Among a range of non-silicon based cells, the films have a relatively higher absorption coefficient that results in high conversion efficiency and long stability. Also, these films require less raw material than what is required by silicon-based ones; hence, small process and material costs.

Nonetheless, difficulty in commercialization has been a downside of solar films as have a buffer layer containing cadmium – a toxic heavy metal. For this, the research team replaced cadmium sulfide buffer layers with zinc-based materials. These materials are not harmful and achieved a conversion efficiency of almost 18%, thus eliminating a hurdle to commercialization.

Technology close to full-on Commercialization

Likewise, the technology is one step closer to commercialization for another factor. Availability of more than seven colors including green, purple, green, and blue which does not require additional process or cost. Moreover, the researchers succeeded to identify a new analysis method that uses photo-pumping terahertz spectroscopy and a mechanism to improve the conversion efficiency of solar cells with zinc-based buffer layers. Being thin, the solar cells can be coated on both a flexible substrate and glass substrate. This implies, the thin solar cells could be bent or folded, expanding their applications as a next-generation eco-friendly source of energy.

With thin-film solar cells, it will contribute to the development of solar power system through the production of color high value-added photovoltaic modules.