Materials of different allogeneic or xenogeneic or autologous origins are widely used as soft-tissue fillers or structural scaffolds in the field of cosmetic surgery, while complications including prosthesis infection, donor site deformity and filler embolization have always been difficult problems for plastic surgeons. The application of novel biomaterials may bring in hopeful solutions for these problems. Recently, some advanced biomaterials, such as regenerative biomaterials can effectively promote the repair of defective tissues, which have been proven to have good therapeutic as well as cosmetic effects in cosmetic surgery. Therefore, biomaterials with active compounds have drawn significant attention for the tissue regeneration of reconstructive and esthetic treatment. Some of these applications have achieved better clinical outcomes than traditional biological materials. This review summarized recent progress and clinical applications of advanced biomaterials in cosmetic surgery.

Among perovskites, the research on cesium lead iodides (CsPbI₃) has attracted a large research community, owing to their all-inorganic nature and promising solar cell performance. Typically, the CsPbI₃ solar cell devices are prepared at various heterojunctions, and working at fluctuating temperatures raises questions on the material stability-related performance of such devices. The fundamental studies reveal that their poor stability is due to a lower side deviation from Goldschmidt’s tolerance factor, causing weak chemical interactions within the crystal lattice. In the case of organic–inorganic hybrid perovskites, where their stability is related to the inherent chemical nature of the organic cations, which cannot be manipulated to improve the stability drastically whereas the stability of CsPbI₃ is related to surface and lattice engineering. Thus, the challenges posed by CsPbI₃ could be overcome by engineering the surface and inside the CsPbI₃ crystal lattice. A few solutions have been proposed, including controlled crystal sizes, surface modifications, and lattice engineering. Various research groups have been working on these aspects and had accumulated a rich understanding of these materials. In this review, at first, we survey the fundamental aspects of CsPbI₃ polymorphs structure, highlighting the superiority of CsPbI₃ over other halide systems, stability, the factors (temperature, polarity, and size influence) leading to their phase transformations, and electronic band structure along with the important property of the defect tolerance nature. Fortunately, the factors stabilizing the most effective phases are achieved through a size reduction and the efficient surface passivation on the delicate CsPbI₃ nanocrystal surfaces. In the following section, we have provided the up-to-date surface passivating methods to suppress the non-radiative process for near-unity photoluminescence quantum yield, while maintaining their optically active phases, especially through molecular links (ligands, polymers, zwitterions, polymers) and inorganic halides. We have also provided recent advances to the efficient synthetic protocols for optically active CsPbI₃ NC phases to use readily for solar cell applications. The nanocrystal purification techniques are challenging and had a significant effect on the device performances. In part, we summarized the CsPbI₃-related solar cell device performances with respect to the device fabrication methods. At the end, we provide a brief outlook on the view of surface and lattice engineering in CsPbI₃ NCs for advancing the enhanced stability which is crucial for superior optical and light applications.

Growth kinetics involved in spontaneous random clustering of perovskite precursors to a particular cesium–lead–bromide (Cs–Pb–Br) nanocrystal (NC) is a poorly understood phenomenon and its spectroscopic investigation is highly challenging. There is scarcely any method that has been optimized yet in which perovskites and their related NCs of a particular size can be grown, viewed, or tuned to another by reaction handling. Here, for the first time, we shed light on the largely overlooked process of growth kinetics of these transformations throughout the reaction trajectory of anionic [PbBr_x]ⁿ⁻ crystallization dictated by Cs⁺ cation and report a simple and direct approach to control the metathesis reaction between two precursors (specifically Cs⁺- and PbBr₂-associated oligomeric complexes) in one solvent at room temperature to monitor the NC growth characteristics in a stepwise manner even in the early stages of nucleation. Altering the molar ratio of the two precursors up to a factor of 10 leads to the formation of three prominent phases (CsPbBr₃, Cs₄PbBr₆, CsBr) as dictated by Cs⁺ to trigger distinct morphological forms (nanobelts, nanoplatelets, rhombohedral NCs, pseudo-rhombic NCs, spherical CsBr NCs, cubic CsBr NCs) including a transient phase that is formed out of linearly self-assembled CsPbBr₃ clusters. Our results pave the way towards understanding spontaneous crystallization to develop well-defined, hassle-free routes for diverse perovskite NCs in a simple yet controlled manner.