How Ternary Cations and Binary Halogens Stabilize Trigonal FA_1–x–yMA_xCs_yPbI_3–zBr_z Perovskites: From a Single Crystal Perspective

Abstract

FA1–x–y MA x Cs y PbI3–z Br z perovskites exhibit excellent stability and optoelectronic performances in solar cells. However, the detailed contributions of each component toward preventing decomposition and phase transition are not understood. Here, we link the contributions of each component to lattice stability and carrier transport from a single crystal perspective, which eliminates the interference of grain boundaries and amorphous perovskite. The exquisite long-term stable trigonal FA1–x–y MA x Cs y PbI3–zBrz SCs under 90% humidity proves that Br is indispensable, which shrinks the lattice and brings contributive distortions for both octahedron (Oh ) and lattice framework, consequently weakening the lattice strain against phase transition. The Br content should be controlled within 15% to avoid phase segregation. Less than 5% content of MA adjusts Oh distortion and promotes carrier transport, but excessive MA increases the extraction risk by H2O. Introduction of Cs (5%) assists Br in bringing sufficient distortion to maintain lattice stability, and exceeding 10% can lead to the phase segregation.

Progress of Metal Halide Perovskite Crystals From a Crystal Growth Point of View

“…The optimized F 0.9 M 0.05 C 0.05 PbI 2.7 Br 0.3 crystals show remarkable water–oxygen stability at 90% humidity, with long carrier lifetime and suitable band gap. [ 118 ]…”

“…The optimized F 0.9 M 0.05 C 0.05 PbI 2.7 Br 0.3 crystals show remarkable water-oxygen stability at 90% humidity, with long carrier lifetime and suitable band gap. [118] 5.3. Doping of Lead-Free Halide Perovskite Crystal Double perovskite crystals have been considered to be environmentally friendly alternatives to lead halide perovskites, with outstanding optoelectronic properties.…”

“…f) Phase change process of the FA 1−x−y MA x Cs y PbI 3−z Br z single crystal at 90% humidity. Reproduced with permission [118]. Copyright 2022, American Chemical Society.…”

Centimeter-size single crystals of 2D hybrid perovskites for shortwave light photodetection with a low detection limit

“…In recent years, organic-inorganic hybrid perovskites have become popular candidates for new optoelectronic materials due to their high carrier mobility, long carrier lifetime, high light absorption, low fabrication cost, and facile fabrication methods. [12][13][14][15][16][17][18][19] More interestingly, the layered two-dimensional (2D) organic-inorganic hybrid perovskite composed of an inorganic framework layer and staggered various organic cations greatly expands the perovskite material system. [20][21][22] Organic large cations as spacers can cut bulk perovskites into twodimensional materials, thereby forming unique quantum well structures and unique optoelectronic properties.…”

Low ion migration and defect density MAPbX3 single crystals grown at low temperature for X-ray detection

“…Yu's group and Ding's group indicated that the Cs ions, Sr ions, PEA ions are also effective in suppressing the ion migration in various perovskite single crystals. 21,22 Huang's group proposed a ligand-assisted solution process, where the 3-(decyldimethylammonio)-propane-sulfonate inner salt formed valence bonds with MAPbI 3 and thus effectively reduced the defect density. The resulting X-ray detectors demonstrated a high sensitivity of 2.6 × 10 6 mC Gy air −1 cm −2 under 100 V bias.…”