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By comparing optical spectral results of both Sn-rich and Sn-poor Cu2ZnSnS4 (CZTS) with the previously calculated defect levels, we confirm that the band-tail states in CZTS originate from the high concentration of 2CuZn + SnZn defect clusters, whereas the deep-donor states originate from the high concentration of SnZn. In Sn-rich CZTS, the absorption, reflectance, and photocurrent (PC) spectra show band-tail states that shrink the bandgap to only ∼1.34 eV, while photoluminescence (PL) and PC spectra consistently show that abundant CuZn + SnZn donor states produce a PL peak at ∼1.17 eV and abundant SnZn deep-donor states produce a PL peak near 0.85 eV. In contrast, Sn-poor CZTS shows neither bandgap shrinking nor any deep-donor-defect induced PL and PC signals. These results highlight that a Sn-poor composition is critical for the reduction of band-tailing effects and deep-donor defects and thus the overcoming of the severe open-circuit voltage (V oc) deficiency problem in CZTS solar cells.

The importance of fucoidan as a functional ingredient in food, health products, and pharmaceutics is well-recognized due to its beneficial biological effects. Fucoidan is usually extracted from brown seaweeds, including Undaria pinnatifida. Fucoidan exhibits beneficial bio-activity and has antioxidant, anticancer, and anticoagulant properties. This review focuses on the biological activity of U. pinnatifida-derived fucoidan and investigates its structure–activity or fraction–activity relationship. It also describes several fucoidan extracts, along with their claimed anticancer effects. It aims to provide information and thoughts for future research such as the development of fucoidan into functional foods or nutraceuticals.

Well-defined giant molecular shape amphiphiles possessing a hydrophilic head with definite shape and size and a linear, hydrophobic polymeric tail with a length suitable to resemble the typical structure of a small-molecule surfactant were synthesized recently and were able to self-assemble into various morphologies in selective solvents. We investigated the self-assembly of shape amphiphiles consisting of a hydrophilic head and one or more hydrophobic tails using the dissipative particle dynamics (DPD) approach. The micellar morphology can transform from vesicles to worm-like cylinders and further to spheres by increasing the interaction parameter between the hydrophilic heads. The simulation results are in agreement with the experimental observations. Furthermore, the self-assembled aggregates exhibit a rich variety of morphological structures, such as spheres, vesicles, worm-like cylinders, pupa-like micelles, disk-like micelles, and segmented rod-like micelles, etc. We demonstrate how to create various morphologies through varying the interaction parameter between hydrophilic head and solvents, the length of hydrophobic tail, the size of hydrophilic head, and the number of hydrophobic tails. Most importantly, we find an interesting strategy for constructing segmented rod-like micelles through changing the size of the hydrophilic head, while using simple polymer tethered molecular nanoparticle amphiphiles as the elementary building blocks. In addition, vesicles prefer to form for more hydrophobic tails under identical conditions in solutions.