Hanul Min

Relieving unwanted strain Although the α-phase of formamidinium lead iodide (FAPbI 3 ) has a suitable bandgap for use in solar cells, it must be stabilized with additional cations. These compositions can adversely affect the bandgap and produce lattice strain that creates trap sites for charge carriers. Kim et al. found that substituting small, equimolar amounts of cesium and methylenediammonium cations for formamidinium reduced the lattice strain and trap densities. The enhancement in open-circ

Maintaining the bandgap The bandgap of the black α-phase of formamidinium-based lead triiodide (FAPbI 3 ) is near optimal for creating high-efficiency perovskite solar cells. However, this phase is unstable, and the additives normally used to stabilize this phase at ambient temperature—such as methylammonium, caesium, and bromine—widen its bandgap. Min et al. show that doping of the α-FAPbI 3 phase with methylenediammonium dichloride enabled power conversion efficiencies of 23.7%, which were mai

For the fabrication of perovskite solar cells (PSCs) using a solution process, it is essential to understand the characteristics of the perovskite precursor solution to achieve high performance and reproducibility. The colloids (iodoplumbates) in the perovskite precursors under various conditions were investigated by UV-visible absorption, dynamic light scattering, photoluminescence, and total internal reflection fluorescence microscopy techniques. Their local structure was examined by in situ X

Abstract Efficient perovskite solar cells (PSCs) are mainly fabricated by a solution coating processes. However, the efficiency of such devices varies significantly with the aging time of the precursor solution used to fabricate them, which includes a mixture of perovskite components, especially methylammonium (MA), and formamidinium (FA) cations. Herein, how the inorganic–organic hybrid perovskite precursor solution of (FAPbI 3 ) 0.95 (MAPbBr 3 ) 0.05 degrades over time and how such degradation

High-performance inorganic-organic lead halide perovskite solar cells (PSCs) are often fabricated with a liquid additive such as dimethyl sulfoxide (DMSO), which retards crystallization and reduces roughness and pinholes in the perovskite layers. However, DMSO can be trapped during perovskite film formation and induce voids and undesired reaction byproducts upon later processing steps. Here, it is shown that the amount of residual DMSO can be reduced in as-spin-coated films significantly through

Abstract The preferential growth of α‐phase formamidinium perovskite (α‐FAPbI 3 ) at low temperatures can be achieved with the incorporation of chloride‐based additives, with methylammonium chloride (MACl) being the most common example. However, compared to other less‐volatile chloride additives, MACl only remains in the growing perovskite film for a short time before evaporating during annealing, primarily influencing the early stages of film formation. In addition, evaporation of MACl as methy

The defect density on the top surface of the perovskite thin film was significantly higher than that in the bulk. A trimming solvent treatment removed the defective top surface, substantially reducing the defect concentration and strain.

This review summarizes recent progress in perovskite materials for concentrated photovoltaics (CPVs), highlighting their properties, addressing thermal challenges, and discussing strategies to enhance CPV performance and feasibility.

Despite its nature of superior thermal and photostability compared to the mixed cation or halide counterparts, cesium lead triiodide (CsPbI 3 ) suffers from the undesired phase transition from β phase to δ phase, which is often initiated at the buried interface. In this study, we demonstrate that the addition of Cl induces the spontaneous formation of the two-dimensional (2D) Ruddlesden-Popper (RP) phase of Cs 2 PbI 2 Cl 2 . The 2D RP Cs 2 PbI 2 Cl 2 predominantly forms at the buried interface d

In article number 1803476, by Sang Il Seok and co-workers, the stability of the perovskite precursor solution and the resulting perovskite thin layer is significantly improved by adding a certain amount of sulfur to the precursor solution. It is found that the sulfur coordinates with the methylammonium cations in the precursor solution to inhibit de-protonation and increase the chemical binding energy due to the interstitial sulfur ions in the perovskite lattice.