Scientists at the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL), in collaboration with researchers at Shanghai Jiao Tong University (SJTU), have reportedly devised a method to improve perovskite-based solar cells, making them more efficient and reliable with higher reproducibility.

The research was funded by the DOE’s SunShot Initiative. It involved hybrid halide perovskite solar cells and revealed treating them with a specific solution of methyl ammonium bromide (MABr) would repair defects, improving efficiency. The scientists converted a low-quality perovskite film with pinholes and small grains into a high-quality film without pinholes and with large grains. This apparently boosted the efficiency of the perovskite film in converting sunlight to 19%, according to NREL.

A research team at the Korea Advanced Institute of Science and Technology (KAIST) and Sungkyunkwan University developed a perovskite-based solar cell that is semi-transparent, highly efficient and functions very effectively as a thermal-mirror.

The team has developed a top transparent electrode (TTE) that works well with perovskite solar cells. In most cases, a key to success in realizing semi-transparent solar cells is to find a TTE that is compatible with a given photoactive material system, which is also the case for perovskite solar cells. The proposed TTE is based on a multilayer stack consisting of a metal film sandwiched between a high refractive-index (high-index) layer and an interfacial buffer layer. This TTE, placed as a top-most layer, can be prepared without damaging ingredients used in perovskite solar cells.

Researchers taking part in a project supported by the Austrian Science Fund FWF, in cooperation with a team of researchers from the Weizmann Institute of Science in Israel and Drexel University in Philadelphia, US, have shown that lead-halide perovskite materials' instability can be considerably reduced through high levels of doping with chloride ions.

The scientists discovered that certain perovskites can hold high levels of chloride ions, and that this enhances the stability of the functional material under certain conditions by up to two orders of magnitude. They examined cesium-lead-iodide perovskites, where a known issue is the stability of the functional phase of this material - under certain conditions, a phase transition occurs and the excellent photovoltaic properties are lost almost immediately. Previous experiments on perovskites (including chloride instead of iodide ions) suggest that doping the material with chloride may enhance its stability. However, achieving this in practice proved to be extremely difficult.

This book covers the fundamentals of organometal perovskite materials and their photovoltaics, including materials preparation and device fabrications.

The book emphases halide perovskites, and it also discusses the opto-electronic properties of perovskite materials and recent progress in perovskite solar cells are described.

Researchers at the University of Virginia and Cornell University have been working on self-assembling metal halide perovskite thin film solar cells for several years. They have recently developed a formulation that raises the hope that commercialization will be possible soon, hopefully within next five years. Such solar panels will simply be sprayed onto a surface, and self-assemble into a high-quality thin film automatically as they dry.

The scientists used high-intensity x-rays to observe the crystallization process to understand precisely how the low temperature self-assembly from a liquid solution to a solid single-crystal film works and observed the high-speed growth of crystallization of metal halide perovskites in real time on the atomic level. By adding different chemicals to the solution, they demonstrated how to control the orientation and speed of crystallization.