TY - JOUR AB - PbS (lead sulfide) colloidal quantum dots consist of crystallites with diameters in the nanometer range with organic molecules on their surfaces, partly with additional metal complexes as ligands. These surface molecules are responsible for solubility and prevent aggregation, but the interface between semiconductor quantum dots and ligands also influences the electronic structure. PbS quantum dots are especially interesting for optoelectronic applications and spectroscopic techniques, including photoluminescence, photodiodes and solar cells. Here we concentrate on the latter, giving an overview of the optical properties of solar cells prepared with PbS colloidal quantum dots, produced by different methods and combined with diverse other materials, to reach high efficiencies and fill factors. AU - Blachowicz, Tomasz AU - Ehrmann, Andrea ID - 645 IS - 5 JF - Applied Sciences KW - colloidal PbS quantum dots KW - quantum dot solar cells KW - semiconductor KW - heterojunction KW - ligand KW - open-circuit voltage KW - short-circuit current KW - power conversion efficiency KW - fill factor SN - 2076-3417 TI - Recent Developments of Solar Cells from PbS Colloidal Quantum Dots VL - 10 ER - TY - JOUR AB - Especially for the potential use as sensors, but also in all other applications in which an interaction with the environment occurs, nanofibrous materials are advantageous due to their large specific surface area. An interesting material for electrospinning is the semiconductor zinc oxide (ZnO) which is often used in photoelectric or sensory applications. Nanofibers containing ZnO can be produced, for example, by electrospinning polyvinylpyrrolidone/zinc nitrate from a dimethylformamide/ethanol solution, followed by calcination to remove the organic phase. Alternatively, the polymer/semiconductor blended nanofibers can be used which are often less brittle, but on the other hand offer less contact between ZnO and the environment. Finally, decorating a nanofiber mat with ZnO offers another possibility to prepare nanofibers with ZnO surface. Possible applications of electrospun ZnO nanofibers or nanofiber mats include gas sensing, microwave absorption, photocatalytic degradation or enhancement of supercapacitor electrodes. This short review gives an overview of the most recent electrospinning and after-treatment techniques to create pure and blended ZnO nanofibers and presents the broad variety of possible applications of this well-known semiconductor with some still surprising properties. AU - Blachowicz, Tomasz AU - Ehrmann, Andrea ID - 637 JF - Journal of Engineered Fibers and Fabrics KW - Electrospinning KW - ZnO KW - nanofibers KW - semiconductor KW - supercapacitor KW - nanorods KW - nanosheets SN - 1558-9250 TI - Recent developments in electrospun ZnO nanofibers: A short review VL - 15 ER - TY - JOUR AB - Developing dye-sensitized solar cells (DSSCs) further is of utmost importance in a time of increasing energy consumption and the necessity to change to renewable energy sources. Opposite to silicon-based solar cells, DSSCs can be produced from low-cost, non-toxic materials. In addition, they can be applied on flexible substrates, enabling even utilization on textile architecture. On the other hand, reaching efficiencies in a similar order of magnitude as with silicon-based solar cells is only possible by highly pure and toxic materials. This is why optimization of DSSCs with non-toxic and affordable materials is of high interest. Here we report on the possibility to increase the TiO2 layer performance by adding a nonionic surfactant, focusing on a non-toxic electrolyte and a natural dye. Our results show that coating the semiconducting layer from a solvent including a surfactant increases the efficiency of the DSSC. To enable comparison with results of other groups which are often reported for very small active areas, we compare three different areas between 0.25 cm² and 6.0 cm² and show that the efficiencies are more than doubled for the smallest active area in comparison to the largest one. This underlines the necessity to perform more research on large-area DSSCs, e.g. by combining several smaller cells, aiming at possible applications on tents or other large textile areas. AU - Udomrungkhajornchai, Suphawit AU - Junger, Irén Juhász AU - Ehrmann, Andrea ID - 622 JF - Optik KW - Dye-sensitized solar cells (DSSCs) KW - Semiconductor KW - TiO2 KW - Nonionic surfactant KW - Triton X-100 KW - Natural dye KW - Anthocyanin KW - Active area SN - 0030-4026 TI - Optimization of the TiO2 layer in DSSCs by a nonionic surfactant VL - 203 ER -