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.
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 (1 O 2). However, we demonstrate that SiNC-dye conjugates synthesized via microwave assistant hydrosilylation reaction produce 1 O 2 with moderate quantum yield () 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.
Silicon quantum dots (SiQDs) are of great interest due to their safety for bioorganisms, especially their low level of toxicity, giving them great potential to become optoelectronic, photonic, and photodynamic...
The condition of teaching materials is good on concepts, principles, and attitudes in Sociology textbooks in senior high schools, which are not relevant to the context of students' lives where sociology is taught, thus causing alienation for educators and students. So the sociology learning that is taught is not indigenous to the socio-cultural conditions of the local community and is more Western (Europeancentric) with universal values. This paper aims to identify contextual teaching materials in sociology learning in senior high schools. The method in this study uses a descriptive qualitative approach with library research, the initial steps in research are by collecting literature related to the research topic. Based on the identification results, sociology teaching materials can be developed through the selection of technology in learning media. Furthermore, contextual learning through internalization and implementation of local wisdom in teaching materials can be used as teachers in examples of each sociology learning material. This paper can contribute ideas about contextual sociology teaching materials that the class can be a laborer in sociology subjects at the high school level.
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