Mixed-halide perovskite synthesis by chemical reaction and crystal nucleation under an optical potential

Abstract

The development of new methods to engineer lead halide perovskite crystals with a controlled band gap and emission properties is an active subject in materials science and chemistry. We present the preparation of mixed-halide lead perovskites by spatially-and temporally-controlled chemical reactions and crystal growth under an optical potential in unsaturated precursor solutions. The crystals are characterized by transmission and photoluminescence spectral measurements and X-ray diffraction analysis. When compared with the spontaneous formation of multiple crystals in saturated precursor solutions, the optical potential creates large single crystals with a high chloride composition, providing distinct blue and green fluorescent crystals of chloride-bromide lead perovskites. We discuss the formation of mixed-halide perovskites from the viewpoints of an increased rate of chemical reaction via the formation and desolvation of precursor complexes and a decreased free energy potential.

Hot‐Spin Casting Synthesis of Freestanding Cs2AgBiBr6 Double Perovskite Facet‐Oriented Microcrystals for Efficient Photodetectors

“…[ 12 ] Additionally, MCs demonstrated enhanced environmental stability and better endurance. Although the synthesis of lead‐based halide perovskite MCs is well established using hot injection, inverse temperature crystallization and laser trapping in a precursor solution, [ 13–16 ] while the synthesis of halide DP MCs is yet to be explored. Recently, Fang et al.…”

Plasmonic Manipulation of Sodium Chlorate Chiral Crystallization: Directed Chirality Transfer via Contact-Induced Polymorphic Transformation and Formation of Liquid Precursor

“…On the contrary, by using a continuous-wave (CW) laser, Sugiyama et al pioneered the concept of “optical trapping-induced crystallization” (OTIC), in which forced crystallization can be induced even from an unsaturated solution by optically trapping crystalline clusters, in 2007 . They demonstrated the OTIC by inducing the forced crystallization of various compounds using conventional laser tweezers. − The force of laser trapping, which governs the controllability of crystallization, is the electrical-field gradient force, F grad , generated by tightly focusing the laser light (electromagnetic (EM) field) with an optical lens. − Assuming that the size of the crystalline clusters is significantly smaller than the wavelength of the trapping laser (Rayleigh particle), F grad , can be expressed as where ⟨ E 2 ⟩ is the time-averaged square of the electric field of the incident laser, α is the polarizability of the target particle, V (= 4π a 3 /3) is the volume of the particle, and ε p and ε m are the dielectric constants of the particles and the surrounding medium, respectively. This “laser trapping-induced crystallization” (LTIC) has successfully achieved the spatiotemporal control of nucleation, ,, polymorph control by switching laser polarization, , liquid–liquid phase separation, and so on.…”

“…where ⟨E 2 ⟩ is the time-averaged square of the electric field of the incident laser, α is the polarizability of the target particle, V (= 4πa 3 /3) is the volume of the particle, and ε p and ε m are the dielectric constants of the particles and the surrounding medium, respectively. This "laser trapping-induced crystallization" (LTIC) has successfully achieved the spatiotemporal control of nucleation, 18,32,41 polymorph control by switching laser polarization, 31,35 liquid−liquid phase 42 separation, and so on. This method continues to pioneer unprecedented crystallization phenomena.…”

Nanoparticle Assembling Dynamics Induced by Pulsed Optical Force

“…Indeed, not only fundamental studies on dynamics and mechanism but also potential application is now being extended by CW laser trapping. Halide perovskites receive much attention as a new class of semiconductor materials for next generation opto‐electronic devices [87,88] . Their crystallization and in‐situ functional modification are demonstrated.…”