@article{ChenMengLiaoetal.2021, author = {Chen, Xing and Meng, Guoyun and Liao, Guanming and Rauch, Florian and He, Jiang and Friedrich, Alexandra and Marder, Todd B. and Wang, Nan and Chen, Pangkuan and Wang, Suning and Yin, Xiaodong}, title = {Highly Emissive 9-Borafluorene Derivatives: Synthesis, Photophysical Properties and Device Fabrication}, series = {Chemistry—A European Journal}, volume = {27}, journal = {Chemistry—A European Journal}, number = {20}, doi = {10.1002/chem.202005185}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256738}, pages = {6274-6282}, year = {2021}, abstract = {A series of 9-borafluorene derivatives, functionalised with electron-donating groups, have been prepared. Some of these 9-borafluorene compounds exhibit strong yellowish emission in solution and in the solid state with relatively high quantum yields (up to 73.6 \% for FMesB-Cz as a neat film). The results suggest that the highly twisted donor groups suppress charge transfer, but the intrinsic photophysical properties of the 9-borafluorene systems remain. The new compounds showed enhanced stability towards the atmosphere, and exhibited excellent thermal stability, revealing their potential for application in materials science. Organic light-emitting diode (OLED) devices were fabricated with two of the highly emissive compounds, and they exhibited strong yellow-greenish electroluminescence, with a maximum luminance intensity of >22 000 cd m\(^{-2}\). These are the first two examples of 9-borafluorene derivatives being used as light-emitting materials in OLED devices, and they have enabled us to achieve a balance between maintaining their intrinsic properties while improving their stability.}, language = {en} } @article{HeDiSanteLietal.2018, author = {He, Jiangang and Di Sante, Domenico and Li, Ronghan and Chen, Xing-Qiu and Rondinelli, James M. and Franchini, Cesare}, title = {Tunable metal-insulator transition, Rashba effect and Weyl Fermions in a relativistic charge-ordered ferroelectric oxide}, series = {Nature Communications}, volume = {9}, journal = {Nature Communications}, doi = {10.1038/s41467-017-02814-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227946}, year = {2018}, abstract = {Controllable metal-insulator transitions (MIT), Rashba-Dresselhaus (RD) spin splitting, and Weyl semimetals are promising schemes for realizing processing devices. Complex oxides are a desirable materials platform for such devices, as they host delicate and tunable charge, spin, orbital, and lattice degrees of freedoms. Here, using first-principles calculations and symmetry analysis, we identify an electric-field tunable MIT, RD effect, and Weyl semimetal in a known, charge-ordered, and polar relativistic oxide Ag2BiO3 at room temperature. Remarkably, a centrosymmetric BiO6 octahedral-breathing distortion induces a sizable spontaneous ferroelectric polarization through Bi3+/Bi5+ charge disproportionation, which stabilizes simultaneously the insulating phase. The continuous attenuation of the Bi3+/Bi5+ disproportionation obtained by applying an external electric field reduces the band gap and RD spin splitting and drives the phase transition from a ferroelectric RD insulator to a paraelectric Dirac semimetal, through a topological Weyl semimetal intermediate state. These findings suggest that Ag2BiO3 is a promising material for spin-orbitonic applications.}, language = {en} }