Perovskites

Quantum dots, a type of semiconductor based on tiny nanometer sized particles, are a cause for excitement in many disciplines thanks to their unique electronic properties. In solar cell technology, quantum dots fabricated from perovskites could have several advantages over more commonly researched “bulk” perovskite materials, and researchers are beginning to take note of these. A group of scientists in China evaluated recent progress in perovskite quantum dot solar cells, noting both strong potential and a long way to go for this early-stage technology.

Conceived by scientists in China, the device combines an integrated carbon-based perovskite solar cell module with a rechargeable aqueous zinc metal cell. The proposed system achieved an overall efficiency of 6.4%, and a steady operation for more than 200 cycles with little performance degradation.

Chinese scientists used perovskitoids as 1D and 0D capping layer materials for the cell’s perovskite layer. These materials enabled an effective and all-around passivation of the perovskite surfaces and grain boundaries, which prevents undesired Shockley-Read-Hall recombination and material degradation. The device achieved a power conversion efficiency of 24.18%, an open-circuit voltage of 1.151 V, a short-circuit current of 25.96 mA/cm2, and fill factor of 80.91%. 

An international group of researchers has achieved the highest fill factor reported for perovskite cells of any size to date. The device was fabricated with a nitrogen-doped titanium oxide (TiOxNy) electron transport layer aimed at improving charge transport between the cell’s perovskite absorber and the electrodes.

The module was fabricated with methylammonium lead iodide (MAPbI3) perovskite solar cells via low-cost spin coating. The panel also achieved an open-circuit voltage of 16.07 V, a short-circuit current of 69.52 mA, and a fill factor of 75.35%.

German scientists have developed a perovskite PV cell with remarkable stability by adding a bilayer of polymers that protects the perovskite from corrosion. This design helps to shield the extremely sensitive perovskite interface and provides the cell with extraordinarily high conductivity.

Italian and Iranian researchers have developed the new “deposition via an antisolvent-soaked applicator” technique, which they describe as an easily scalable process to produce uniform, pinhole-free perovskite films. They tested the process on a 6.7%-efficient solar cell based on a polyethylene terephthalate substrate, raising its power conversion efficiency by 82%.

Researchers in Switzerland have replaced the electron transport layers in perovskite solar cells with a thin layer of quantum dots. On an area of 0.08cm², they achieved a record efficiency of 25.7% and high operational stability.

Scientists at the Technische Universität Dresden, in Germany, have found that photon recycling and light scattering effects greatly improve light emission in perovskite solar cells, thereby boosting the upper limit for their efficiency to 31.3%.

Lithuanian scientists built the panel with 23.9% efficient solar cells with operational stability of over 1000 h. The module has an active area of 26 cm2.