High-throughput particle focusing and separation in split-recombination channel

Inertial microfluidic has been widely applied to manipulate particles or bio-sample based on the inertial lift force and Dean Vortices. This technology provides significant advantages over conventional technologies, including simple structure, high throughput and freedom from an external field. Among many inertial microfluidic systems, the straight microchannel is commonly used to produce inertial focusing, which is a phenomenon that particles or cells are aligned and separated based on their size under the influence of inertial lift force. Besides the inertial lift force, flow drag forces induced by the geometrical structures of microchannel can also affect particle focusing. Herein, a split-recombination microchannel, consisting of curved and straight channels, is proposed to focus and separate particles at high flow rate. As compared with the straight channel, the particle focusing in the split-recombination channel is greatly improved, which results from the combined effects of the inertial lift force, the curvature-induced Dean drag force and the structure of split and recombination. Moreover, the distribution of different-sized particles in designed microchannel is investigated. The results indicate that the proposed microchannel not only enhances the particle focusing but also enables the separation of different-sized particles with high throughput. Finally, it is discovered that the larger length of straight channel and curvature radius of curved channel can result in a more efficient particle separation. Another important feature of designed split-recombination microchannel is that it can be arranged in parallel to handle large-volume samples, holding great potential in lab-on-a-chip applications.

On the absence of triplet exciton loss pathways in non-fullerene acceptor based organic solar cells

Recombination to donor and acceptor triplet states should be energetically favourable. However, this recombination channel is not observed in operational devices.

Перестройка спектров электролюминесценции в гетероструктурах II типа n-InAs/n-InAsSbP

Single heterostructures of type II n ^+-InA s/n ^0-InAs_0.59Sb_0.16P_0.25, based on an intentionally undoped epitaxial layer with an electronic type of conductivity are obtained by metalorganic vapor phase epitaxy (MOVPE). In the heterostructure, a transition layer of modulated composition is formed near the heterointerface in the bulk of the quaternary solid solution. The existence of a radiative recombination channel due to the presence of localized hole states in quantum wells formed in the transition layer near the heterointerface is shown. It is demonstrated that the maximum of the intensity of the electroluminescence spectrum of the heterostructure under study is rearranged when a forward external bias is applied. The results of this study can be used in the development of tunable light-emitting diodes operating in the midinfrared range of 2–4 μm.

Interrelation between Light Emitting and Structural Properties of Si Nanoclusters Embedded in SiO2 and Al2O3 Hosts

ABSTRACTThe present work deals with the comparative investigation of Si-ncs embedded in SiO2 and Al2O3 dielectrics grown by RF magnetron sputtering on fused quarts substrate. The effect of post-deposition processing on the evolution of microstructure of the films and their optic and luminescent properties was investigated. It was observed that photoluminescence (PL) spectra of Six(SiO2)1-x films showed one PL band, which peak position shifts from 860 nm to 700 nm when the x decreases from 0.7 to 0.3. It is due to exciton recombination in Si-ncs. For Six(Al2O3)1-x films, several PL bands peaked at about 570-600 nm and 700-750 nm and near-infrared tail or band peaked at about 800 nm were found. Two first PL bands were ascribed to different oxygen-deficient defects of oxide host, whereas near-infrared PL component is due to exciton recombination in Si-ncs. The comparison of both types of the samples showed that the main radiative recombination channel in Six(SiO2)1-x films is exciton recombination in Si-ncs, while in Six(Al2O3)1-x films the recombination via defects prevails due to higher amount of interface defects in the Six(Al2O3)1-x caused by stresses.