Researchers develop new materials to match with extremely high efficiency perovskite solar cells

A group of researchers at Kaunas University of Technology fabricated materials that were used to build an exemplary perovskite solar module displaying an efficiency of 21.4 percent. This was achieved by making the active solar cell layer passive, which amplifies the efficiency of the cell and improves its stability significantly.

Perovskite solar cells today is one of the fastest developing solar cell technologies. Structurally, perovskite solar cells are lightweight, thin-layered, flexible, and are made of low cost materials. However, this model of solar cell faces a key challenge: Quick degradation of perovskite material under environmental conditions.

Meanwhile, pacifying of solar cell layer is a simple yet effective means to improve the stability of perovskite cells and has been considered as one of the most useful strategies to remove the defects of perovskite materials and their downsides. This results in passivated perovskite surface to become more resistant to ambient conditions as temperature or humidity, and more stable to extend the durability of the device.

The work of KTU chemists along with researchers from some other academic institutions has led to significant improvement in the stability of perovskite solar cells using passivation. The method leads to chemically inactivity of the perovskite surface during passivation thereby removing the defects of perovskite that occur during manufacture. The resultant perovskite solar cells attain an efficiency 23.9 % with long term operational stability.

In fact, passivation has been used earlier, with a 2D layer of perovskite formed on the traditional 3D perovskite light absorber so far. This makes it difficult for carriers to move, in particular at higher temperatures. This is critical to avoid to prevent solar cells from becoming hot.  

Researchers engineer next-gen solar powered batteries

Secondary batteries such ad lithium-ion ones need to be recharged once the stored energy is exhausted. In an effort to decrease the dependency on fossil fuels, scientists have been seeking sustainable ways to recharge secondary batteries.

In a recent development, a graduate student at TIFR Hyderabad and a team have put together a close-packed lithium ion battery with photosensitive matter that can be charged directly with solar energy.

Meanwhile, the initial efforts to direct solar energy for the recharge of batteries involved use of photovoltaic cells as separate entities. Using photovoltaic cells, solar energy is converted into electrical energy which is eventually stored as chemical energy in batteries. The stored energy is used to power electronic devices. The transfer of energy from one component to the other results in loss of some energy.

In fact, to prevent energy loss, this involved a shift toward exploring the use of photosensitive parts inside a battery. The advancement in integrating photosensitive components within a battery to result in the formation of improved compactness batteries has been substantial.

While existing solar batteries display improved design, they still have some drawbacks. Some disadvantages associated with various types of solar batteries are: Reduced ability to trap adequate solar energy, use of organic electrolyte that may cause corrosion of photosensitive organic parts inside a battery, and side products that are formed that hinder sustained performance of a battery in the long term.

For the study, the research associates sought to explore new photosensitive materials which can also include lithium and construct a solar battery that would be free of leak and function efficiently in ambient conditions.

Solar batteries that have two electrodes usually contain a photosensitive dye in one of the electrodes physically mixed with stabilizing components that helps to drive the flow of electrons through the battery.