Recently, tuning the green emission of CsPbBr₃ quantum dots (QDs) to blue through quantum size and confinement effects has received considerable attention due to its remarkable photophysical properties. However, the synthesis of such a blue-emitting QD has been challenging. Herein, supersaturated recrystallization was successfully implemented at room temperature to synthesize a broadband blue-emitting ZnBr₂-doped CsPbBr₃ QD with an average size of ~3 nm covering the blue spectrum. The structural and optical properties of CsPbBr₃ QDs demonstrated that QD particle size may decrease by accommodating ZnBr₂ dopants into the perovskite precursor solution. Energy-dispersive spectroscopy confirmed the presence of zinc ions with the QDs. This work provides a new strategy for synthesizing strongly quantum-confined QD materials for photonic devices such as light-emitting diodes and lighting.

The phase change of all-inorganic cesium lead halide (CsPbI₃) thin film from yellow δ-phase to black γ-/α-phase has been a topic of interest in the perovskite optoelectronics field. Here, the main focus is how to secure a black perovskite phase by avoiding a yellow one. In this work, we fabricated a self-doped CsPbI₃ thin film by incorporating an excess cesium iodide (CsI) into the perovskite precursor solution. Then, we studied the effect of organic additive such as 1,8-diiodooctane (DIO), 1-chloronaphthalene (CN), and 1,8-octanedithiol (ODT) on the optical, structural, and morphological properties. Specifically, for elucidating the binary additive–solvent solution thermodynamics, we employed the Flory–Huggins theory based on the oligomer level of additives’ molar mass. Resultantly, we found that the miscibility of additive–solvent displaying an upper critical solution temperature (UCST) behavior is in the sequence CN:DMF > ODT:DMF > DIO:DMF, the trends of which could be similarly applied to DMSO. Finally, the self-doping strategy with additive engineering should help fabricate a black γ-phase perovskite although the mixed phases of δ-CsPbI₃, γ-CsPbI₃, and Cs₄PbI₆ were observed under ambient conditions. However, the results may provide insight for the stability of metastable γ-phase CsPbI₃ at room temperature.

All-inorganic perovskite semiconductors have received significant interest for their potential stability over heat and humidity. However, the typical CsPbI₃ displays phase instability despite its desirable bandgap of ~1.73 eV. Herein, we studied the mixed halide perovskite CsPbI₂Br by varying the silver doping concentration. For this purpose, we examined its bandgap tunability as a function of the silver doping by using density functional theory. Then, we studied the effect of silver on the structural and optical properties of CsPbI₂Br. Resultantly, we found that ‘silver doping’ allowed for partial bandgap tunability from 1.91 eV to 2.05 eV, increasing the photoluminescence (PL) lifetime from 0.990 ns to 1.187 ns, and, finally, contributing to the structural stability when examining the aging effect via X-ray diffraction. Then, through the analysis of the intermolecular interactions based on the solubility parameter, we explain the solvent engineering process in relation to the solvent trapping phenomena in CsPbI₂Br thin films. However, silver doping may induce a defect morphology (e.g., a pinhole) during the formation of the thin films.

This study explores making sustainable bio-bricks using materials readily available in the local environment: clay, sand, lime, termite mound soil (TMS), and rice husk. The present study examined these materials, both individually and when combined, to understand their microscopic structure, mineral composition, and thermal stability. Scanning electron microscopy (SEM) revealed a dense, tightly bonded structure in the composite bio-brick, with well-fitted particles enhancing its strength. X-ray diffraction (XRD) confirmed this, identifying the main crystalline phases in the bio-brick: quartz, kaolinite, portlandite, and amorphous silica. The presence of these minerals suggests excellent chemical compatibility among the components, enabling the material to undergo effective reactions that promote hardening and strength development. Thermogravimetric analysis (TGA) revealed the material's thermal stability, showing it remains stable even above 540°C. This composite performs well under high temperatures, but it excels when the mixture is precise: 45% clay, 22% sand, 6% termite mound soil, 12% lime, and 15% rice husk. At these ratios, it absorbs the least amount of water—just 14.15%—and achieves a compressive strength of 7.56 MPa. Importantly, these bio-bricks demonstrated a significant reduction in global warming potential, decreasing CO ₂ emissions by 95% compared to traditional bricks. This study highlights the potential of utilizing local resources to produce sustainable building materials, contributing to eco-efficient construction practices and reducing reliance on non-renewable resources. The findings suggest that bio-bricks could offer a viable alternative for low-income housing, fostering local economic development and promoting environmentally sustainable building solutions.