An unprecedentedly stable CH3NH3PbI3 film synthesized by a modified chemical vapor transport method is demonstrated. The results show that the crystal structure, light absorption, and device efficiency do not degrade after storing for 100 d in air with 40% relative humidity, while the conventional solution-processed perovskites are usually stable for less than 20 d in similar conditions.

The application of first-principles computational methods to the study of ferroelectric perovskites has greatly expanded our theoretical understanding of this important class of materials. These methods have most recently been applied to an increasingly wide range of ferroelectric materials, with special attention to their lattice dynamics, phase transitions, and dielectric and piezoelectric pr...

A pressure-induced crossover from normal Ferroelectic-to-Relaxer behavior has been observed in single crystal [Pb(Zn1BNb~)03]o.go5 (PbTi03)o.og5,or PZN 9.5% PT. Analogy with similar observations for other perovskites indicates that this crossover is a general feature of compositionally-disordered soft mode ferroelectrics. The Pressure-Temperature phase diagram has been also determined.

The conclusions reached by a diverse group of scientists who attended an intense 2-day workshop on hybrid organic-inorganic perovskites are presented, including their thoughts on the most burning fundamental and practical questions regarding this unique class of materials, and their suggestions on various approaches to resolve these issues.

Published as part of the Accounts of Chemical Research special issue “Lead Halide Perovskites for Solar Energy Conversion”. David A. Egger,*,† Andrew M. Rappe,*,‡ and Leeor Kronik*,† †Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel ‡The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania...

In the end of 1940s young soviet scientist Georgii Smolenskii discovered ferroelectric properties in lead titanate (PbTiO 3) [1] and found an anomaly in the temperature dependence of the dielectric constant in lead zirconate (PbZrO 3) [1,2]. This encouraging result was also independently obtained by G. Shirane [3] and G. Roberts [4]. Based on this data, Smolenskii came to the conclusion that Pb...