Silicon quantum dots (SiQDs) are of great interest because they are believed to be harmless to living organisms, mainly due to their low toxicity.

Air‐stable inorganic cesium lead iodide (CsPbI₃) perovskite thin films with a bandgap of 1.7 eV are a promising candidate for tandem cell solar cells, comprising a perovskite top cell with a crystalline silicon bottom cell. The device design and simulations are important to develop high‐efficiency photovoltaic devices. However, knowledge of complex optical constants of the CsPbI₃ thin films is mandatory to complement such tasks. Herein, air‐stable inorganic CsPbI₃ perovskite thin films are prepared using one‐step synthesis through a spin‐coating method. Variable angle spectroscopic ellipsometry (VASE) is then conducted at five angles (43.9°, 48.9°, 53.9°, 58.9°, and 63.9°) to obtain ellipsometric data (Ψ and Δ). The thickness nonuniformity model of the perovskite thin film combined with an effective medium approximation for describing rough surface is adopted to achieve excellent fitting. The complex optical constants of the CsPbI₃ thin film are experimentally obtained in the wavelength range of 300–1200 nm. The present results open the door for design and simulations on high‐efficiency CsPbI₃/c‐Si tandem solar cells.

Silicon nanocrystals (SiNCs) are regarded as a green and environmentally friendly material when compared with other semiconductor nanocrystals. Ultra-small SiNCs (with the size 4.6–5.2 nm) demonstrate strong UV absorption and photoluminescence in the near infrared (NIR) range with the high photoluminescence quantum yield (PLQY) up to 60%. In contrast to nanoporous silicon, ultra-small SiNCs do not possess an intrinsic ability to generate singlet oxygen (¹O₂). However, we demonstrate that SiNC-dye conjugates synthesized via microwave assistant hydrosilylation reaction produce ¹O₂ with moderate quantum yield (Φ_Δ) up to 27% in cyclohexane. These interesting results were obtained via measurements of singlet oxygen phosphorescence at 1,270 nm. SiNCs play an important role in the production of singlet oxygen as SiNCs harvest UV and blue radiation and transfer absorbed energy to a triplet state of the attached dyes. It increases the population of the triplet states and leads to the enhancement of the singlet oxygen generation. Simultaneously, the SiNC-dye conjugates demonstrate NIR luminescence with the PLQY up to 22%. Thus, the luminescence behavior and photosensitizing properties of the SiNC-dye conjugates can attract interest as a new multifunctional platform in the field of bio-applications.

Herein, we report a microwave-assisted hydrosilylation (MWH) reaction for the surface passivation of silicon nanocrystals (Si-NCs) with linear alkenes.

Silicon nanocrystals with dyes covalently anchored to the crystal surface demonstrate improved visible light absorption and near-infrared luminescence enhancement – up to ∼270% and ∼140% under excitation with blue and green light, respectively.

The fabrication of ballpoint-ink might open up a new perspective on physico-chemical solubility thermodynamics. In this report, we present a method to encapsulate inorganic pigments, such as Fe(CNS)₃ (red), Fe₂Fe(CN)₆ (blue), CdS (yellow), and CuS (black) into w/o microemulsion gels. The area of w/o microemulsions was first determined by titrating surfactants Tween-60 into the given composition of water and cyclohexane in the pseudo-three phase diagram. Three prosperous phase areas were successfully mapped using this method, namely: microemulsion (w/o, and o/w) or (μE), lamellar liquid crystal (L_α), and hexagonal liquid crystal (H_α), respectively. The results show that inorganic pigments were well soluble in the w/o microemulsion gel of the Tween-60/cyclohexane/water system. The highest solubility of inorganic pigments in the microemulsion gel is 3.63 ± 0.05 mg g⁻¹ for the red pigment of Fe(CNS)₃, and the lowest is 2.92 ± 0.05 mg g⁻¹ for the yellow pigment of CdS. Hence, the solubility limit distribution for all pigments is 2.9 ± 0.05 <>3.63 ± 0.05 mg g⁻¹. The cation and anion size strongly affected the inorganic pigments' solubility in the w/o-microemulsion system. Some quantity of the ink-made of inorganic pigments encapsulated in the microemulsion gel has been inserted into empty ballpoint sleeves as prototypes. The resulting self-made inks demonstrated that the physical appearances of the ink could mimic the factory-made inks. Nevertheless, the self-made ink should be investigated further for long lifespan use, especially for long-term stability and corrosion resistance.