Scientists at the University of Cambridge studying perovskite materials for use in solar cells and flexible LEDs have discovered that they can be more efficient when their chemical compositions are less ordered, simplifying production processes and lowering cost.

The surprising findings are the result of a collaborative project, led by Dr. Felix Deschler and Dr. Sam Stranks.

Researchers from Helmholtz-Zentrum Berlin (HZB), headed by Prof. Susan Schorr and Dr. Joachim Breternitz, have achieved a breakthrough in understanding the crystalline structure of hybrid halide perovskites. The team investigated crystalline samples of methylammonium lead iodide (MAPbI₃), the most prominent representative of this class of materials, at the Diamond Light Source synchrotron (DLS) in the United Kingdom using high-resolution single-crystal diffraction. This approach provided data for a more in-depth analysis of the crystalline structure of this material.

They were also able to clarify, whether ferroelectric effects are possible at all in this hybrid halide perovskite. Ferroelectric domains can have favorable effects in solar cells and increase their efficiency. However, measuring this effect in samples is difficult - a null result can mean that there is either no ferroelectric effect or that the ferroelectric domains cancel one another's effects out.

Researchers at Saudi Arabia’s King Abdullah University of Science and Technology have demonstrated a method that could improve the stability of perovskite solar cells. The group found adding an organic dopant served to increase the strength of chemical bonds between organic and inorganic elements of a perovskite.

Stabilizing perovskite solar cells would solve a key issue that s currently delaying commercialization of PSCs and could provide a more comprehensive solution than other approaches which center on managing perovksite’s inherent instability in the atmosphere by encapsulating them. Another recent study, from Rice University in the United States, found adding indium in an all-inorganic perovskite limited defects and improved stability.

A research group led by Prof. Liu Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) and Prof. Yang Dong at Shaanxi Normal University have developed high efficiency semi-transparent perovskite solar cells by using MoO₃ sandwiched gold nanomesh (MoO₃/Au/MoO₃) multilayer as the transparent electrode. Combined with a superior heterojunction silicon solar cell, a high efficiency four-terminal perovskite/silicon tandem solar cell was obtained.

Tandem/multijunction structure has been proven to be an effective way to break the Shockley-Queisser limit. To obtain a high efficiency tandem solar cell, the key is to fabricate transparent electrode with high conductivity as well as high transparency through a mild method.