Engineering topics
Cui, Yongjie
Publications and source records attributed to Cui, Yongjie.
The synergistic effects of central core size and end group engineering on performance of narrow bandgap nonfullerene acceptors
Understanding the relationship between the molecular structure and photoelectric properties of fused-ring non-fullerene acceptors (NFAs) is of far-reaching significance to the development of organic solar cells (OSCs). Herein, six NFAs based on multiple thiophenes (4 T, 6 T and 8 T) are employed to systematically probe the synergistic effects of extending central core size and terminal fluorination. The absorption results manifest that the molecular absorption is comprehensively affected by molecular crystallinity, planarity, conjugation length and intramolecular electron push–pull effect, simultaneously. The intensity of electron push–pull effect is not only related to the electron-donating ability of central core and the electron-withdrawing ability of end group, but also may be related to the distance between the positive and negative centers. The extension of central core leads to the more planar backbone and stronger crystallinity of NFAs, and less energy loss (E loss ) in its based OSC. Compared with the extension of central core, terminal fluorination has a greater impact on molecular photoelectric properties. The terminal fluorination significantly enhances the push–pull effect, lowers the energy levels, and slightly increases the vibrational relaxation. As a result, the strongest crystallinity and coplanarity of 8TIC-4F lead to a low vibrational relaxation of 0.18 eV, which makes PTB7-Th:8TIC-4F device exhibit a small E loss of 0.51 eV and a high efficiency of 10.4%. In addition, the fluorinated 6TIC-4F with suitable core size exhibits suitable energy level, absorption, crystallization, and phase separation morphology, making its as-cast device up to 11.61% efficiency. Finally, to the best of the authors’ knowledge, the PCE of 11.61% for PTB7-Th:6TIC-4F based device without any treatment is one of the highest values reported for the NAFs with over 1000 nm absorption.
Passive magnetic devices
A passive magnetic device (PMD) has a base electrode, a multi-port signal structure (MPSS), and a substrate therebetween. The MPSS has a central plate residing in a second plane and at least two port tabs spaced apart from one another and extending from the central plate. The substrate has a central portion that defines a mesh structure between the base electrode and the central plate of the multi-port signal structure. A plurality of magnetic pillars are provided within the mesh structure, wherein each of the plurality of the magnetic pillars are spaced apart from one another and surrounded by a corresponding portion of the mesh structure. The PMD may provide a magnetically self-biased device that may be used as a radio frequency (RF) circulator, an RF isolator, and the like.