Schematic illustration showing that the charge recombination and collection under above-bandgap excitation is severely affected by surface traps

Hybrid Perovskites

New photovoltaic materials have been searched for in the past decades for clean and renewable solar energy conversion with an objective of reducing the levelized cost of electricity, that is, the unit price of electricity over the course of the device lifetime.

An emerging family of semiconductor materials — organic–inorganic halide perovskites, OIHPs, — are the focus of the photovoltaic research community owing to their use of low cost, nature-abundant raw materials, low-temperature and scalable solution fabrication processes, and, in particular, the very high power conversion efficiencies that have been achieved within the short time of their development.

In a review published in Nature Reviews, researchers in the Huang Group summarize and critically assess the most recent advances in understanding the physical properties of both 3D and low-dimensional OIHPs that favour a small open-circuit voltage deficit and high power conversion efficiency. They survey several prominent topics in the field, and the unique properties of OIHPs are explained, including defect physics, ferroelectricity, exciton dissociation processes, carrier recombination lifetime and photon recycling.

The group members also critically analyze the impact of ion migration on solar cell efficiency, and stability. Finally, they present a discussion on the remaining challenges in the commercialization of OIHP photovoltaics.