Researchers from Nigeria’s African University of Science and Technology (AUST), working with scientists from Worcester Polytechnic Institute in the U.S., have suggested a novel fabrication method for perovskite solar cells.

Inspired by previous work on other organic thin-film solar cell materials, the group investigated the effects of pressure on perovskite cell production by using computational analysis and practical experimentation. A previous study at Brown University showed how the correct application of stress could heal cracks in perovskite solar cells but little information is available about how pressure could be applied to production processes.

Some light-emitting diodes (LEDs) created from perovskites emit light over a broad wavelength range. Scientists from the University of Groningen have now shown that in some cases, the explanation of this phenomenon is incorrect. Their new explanation should help scientists to design perovskite LEDs capable of broad-range light emission.

Wide-field photoluminescence micrographs (230_175 μm) show how somePerovskite flakes appear bright green over their entire area (left panel), whilst other flakesexhibit a distinctly red-shifted emission (right panel). Credit: University of Groningen

Low-dimensional (2D or 1D) perovskites emit light in a narrow spectral range and are therefore used to make light-emitting diodes of superior color purity. However, in some cases, researchers have noted a broad emission spectrum at energy levels below the narrow spectrum. This has attracted great interest as it could be used to produce white light LEDs more easily compared to current processes. To design perovskites for specific purposes, however, it is necessary to understand why some perovskites produce broad-spectrum emissions while others emit a narrow spectrum.

Two new studies have been recently released on the topic of advances in the use of plasmonic enhancement to improve performance and stability of perovskite solar cells.

In recent years, plasmonic enhancement has been used in a wide variety of research aimed at improving the efficiency and thermal stability of perovskite solar cells. The technique consists of enhancing the cells’ electromagnetic field through metal nanostructures, which in turn improves the devices’ low optical absorption in the visible spectrum.

A research team led by Juan Casanova and Eduard Llobet from the Departamento de Ingeniería Electrónica, Eléctrica y Automática at the Universitat Politècnica de València (URV), used graphene and perovskites to create a nanosensor that detects nitrogen dioxide with 300% improved sensitivity.

The team used graphene that is hydrophobic (water and moisture-resistant) and sensitive in gas detection, but with some limitations: it is not very selective and its sensitivity declines over time. In addition, the researchers used perovskites, a crystalline-structure material commonly used in the field of solar cells. However, they quickly deteriorate when they are exposed to the atmosphere. That's the reason why the team decided to combine perovskites with a hydrophobic material able to repel water molecules - in order to prove they can prevent or slow down their deterioration.