Wanyi Nie

TL;DR: A solution-based hot-casting technique is demonstrated to grow continuous, pinhole-free thin films of organometallic perovskites with millimeter-scale crystalline grains that are applicable to several other material systems plagued by polydispersity, defects, and grain boundary recombination in solution-processed thin films.

TL;DR: Thin films of near-single-crystalline quality are produced, in which the crystallographic planes of the inorganic perovskite component have a strongly preferential out-of-plane alignment with respect to the contacts in planar solar cells to facilitate efficient charge transport.

TL;DR: It is reported that, counterintuitive to classical quantum-confined systems where photogenerated electrons and holes are strongly bound by Coulomb interactions or excitons, the photophysics of thin films made of Ruddlesden-Popper perovskites with a thickness exceeding two perovkite-crystal units is dominated by lower-energy states associated with the local intrinsic electronic structure of the edges of the perovSKite layers.

TL;DR: It is shown that the slow photocurrent degradation in thin-film photovoltaic devices is due to the formation of light-activated meta-stable deep-level trap states, and the creation of small polaronic states involving localized cooperative lattice strain and molecular orientations emerges as a credible microscopic mechanism requiring further detailed studies.

TL;DR: Correlated, in situ structural and device characterizations reveal that light-induced lattice expansion benefits the performances of a mixed-cation pure-halide planar device, boosting the power conversion efficiency from 18.5 to 20.5%.