Advanced Strategies to Tailor the Nucleation and Crystal Growth in Hybrid Halide Perovskite Thin Films

Abstract

Remarkable improvement in the perovskite solar cell efficiency from 3.8% in 2009 to 25.5% today has not been a cakewalk. The credit goes to various device fabrication and designing techniques employed by the researchers worldwide. Even after tremendous research in the field, phenomena such as ion migration, phase segregation, and spectral instability are not clearly understood to date. One of the widely used techniques for the mitigation of ion migration is to reduce the defect density by fabricating the high-quality perovskite thin films. Therefore, understanding and controlling the perovskite crystallization and growth have become inevitably crucial. Some of the latest methods attracting attention are controlling perovskite film morphology by modulating the coating substrate temperature, antisolvent treatment, and solvent engineering. Here, the latest techniques of morphology optimization are discussed, focusing on the process of nucleation and growth. It can be noted that during the process of nucleation, the supersaturation stage can be induced faster by modifying the chemical potential of the system. The tailoring of Gibbs free energy and, hence, the chemical potential using the highly utilized techniques is summarized in this minireview. The thermodynamics of the crystal growth, design, and orientation by changing several parameters is highlighted.

Dynamics in Blue Emitting Metal Halide Perovskites for Light Emitting Diodes

“…Nucleation can be either homogeneous, occurring spontaneously within the solution, or heterogeneous, occurring on external sites such as at surfaces. During growth of perovskite films, the substrate typically acts as a site for heterogeneous nucleation and can be tuned to moderate growth 82,85,86 . Nucleation and growth from solution can be qualitatively described in a LaMer diagram 87 , figure 6.…”

“…The growth of perovskite films can be controlled by tuning of both the nucleation and crystal growth. Accelerating the supersaturation, through temperature adjustment, or by the use of anti-solvents, can increase nucleation rate and nuclei density creating polycrystalline compact films with lower surface roughness and small grain size 85 . In combination with additives this can produce spatially and dielectrically confined crystals with high quantum yields, leading to efficient PeLEDs.…”

“…This can lead to a more controlled growth process, dominated by diffusion and coalescence, which has shown to increase film homogeneity, crystallinity, reduce defects, and producing efficient LEDs 89,90 . The perovskite film formation is further influenced by factors such as interfacial energies, the wettability on the substrate surface and interaction between solutes and the solvents, forming intermediate complexes 82,85,86 . Growth of perovskite thin films is hence a complex process with much more to study and discover.…”

Optimal Conditions for Preparation of Perovskite Materials for Optoelectronic Devices

“…The credit goes to the researchers/scientists working around the planet utilizing different device fabrication and design methods [9]. Interestingly, perovskites blend the properties of inorganic materials like high photoluminescence quantum yield, long carrier diffusion lengths, high color purity together with the properties of organic materials such as solution processability at low temperature, and high production yield [10].…”

“…Also, the issue of lead toxicity though very minute in quantity can be solved by using effective encapsulation technology to reduce Pb leakage into the surroundings and recycling technique. In conjunction with above issues, the fabrication process of large-scale devices plus fabrication parameters should be broadly studied and meticulously modified to obtain high-quality perovskite films [6,7,10].…”