Thermodynamically and Kinetically Controlled Nucleation and Growth of Halide Perovskite Single Crystals

Abstract

Halide perovskites are ideal for next‐generation optical devices and photovoltaics. Although perovskite single‐crystals show reproducible optoelectronic properties, significant variations in the crystal size, anisotropy, density, defects, photoluminescence (PL), and carrier lifetime affect the sample properties and device performances. Homogenous size and shape FA/MAPbBr3 single microcrystals (MCs) with controlled edge lengths, crystal densities, PL lifetimes, and PL intensities are prepared by thermodynamically controlling and kinetically separating the crystal nucleation‐growth processes using optimum N‐cyclohexyl‐2‐pyrrolidone (CHP) concentration. The crystal growth kinetics at different CHP concentrations and temperatures are estimated spectroscopically by measuring the concentration of Pb (II). High‐density cubic MCs with a homogenous size distribution, high PL intensities, and long PL lifetimes are obtained within minutes at high temperatures by the controlled addition of the pyrrolidone derivative. Conversely, the crystal size nonlinearly increases with time at low temperatures. The isotropically grown high‐density single crystals at controlled nucleation‐growth rates at 190 °C with 20% CHP show the highest PL intensity and the longest PL lifetimes. This method offers thermodynamic and kinetic control of perovskite single‐crystal growth with shape control.

Perovskite Paradigm Shift: A Green Revolution with Lead-Free Alternatives in Photocatalytic CO2 Reduction

“…Accordingly, when the solution concentration exceeds the critical point of nucleation, nuclei aggregate to form crystals. On the contrary, clustering of nuclei will not occur if the solution concentration is below the critical point of nucleation. , The synthesis of LFHPs is analogous to that of the Pb-based halide perovskites, except that the Pb precursor is replaced with the corresponding B-site cation precursor. In this section, representative methods for the synthesis of LFHPs including hot-injection, solvothermal, ligand-assisted reprecipitation, ligand-free anti-solvent recrystallization, and solvent evaporation as well as sonochemistry and mechanochemistry will be covered.…”

Fine Purification Engineering Enables Efficient Perovskite QLEDs with Efficiency Exceeding 23%

“…High photoelectric performance and high stability are the keys to the application of PeQDs. − During the synthesis of PeQDs, their performance is subject to the nucleation and growth process, crystal structure, defect state, and surface ligand characteristics. − On the nucleation growth process, many studies are focusing on. ,− By changing the reaction pathway, controllable nucleation and growth of perovskite QDs have been achieved. Combined with in situ absorption spectroscopy, the dynamic characteristics of PeQDs’ crystal growth have been revealed. , For the control of crystal structure, the doping strategy of components or elements provides a very rich managing effect on the optical band gap, luminescence behavior, carrier dynamics, and QLEDs’ performance. , Afterward, the types of surface ligands outside of PeQDs, including long chain, short chain, and ligands with special photoelectric properties, have a huge impact on their photoelectric properties. − However, for PeQD-based QLED, not only the type of surface ligands, but also the number of ligands will dominate the carrier transport and radiative recombination efficiency inside the device. − Thus, the purification process after synthesis is crucial, will directly affect the PeQDs’ ligand state and crystal structure, and even redefine their photoelectric properties.…”