Blue host materials for organic light-emitting diodes (OLEDs) based on silicon-cored (tetraphenylsilane) anthracene derivatives are synthesized. These compounds, with a non-coplanar molecular structure, have high glass-transition temperatures and good amorphous-film-forming capabilities. When doped with a blue-fluorescent dopant, blue emission with high color purity and high efficiency, up to 7.5 cd A(-1) and 6.3%, is achieved.

A novel host material containing silicon‐cored spirobifluorene derivative (SBP‐TS‐PSB), is designed, synthesized, and characterized for red phosphorescent organic light‐emitting diodes (OLEDs). The SBP‐TS‐PSB has excellent thermal and morphological stabilities and exhibits high electroluminescence (EL) efficiency as a host for the red phosphorescent OLEDs. The electrophosphorescence properties of the devices using SBP‐TS‐PSB as the host and red phosphorescent iridium (III) complexes as the emitter are investigated and these devices exhibit higher EL performances compared with the reference devices with 4,4′‐N,N′‐dicarbazole‐biphenyl (CBP) as a host material; for example, a (piq)2Ir(acac)‐doped SBP‐TS‐PSB device shows maximum external quantum efficiency of ηext = 14.6%, power efficiency of 10.3 lm W−1 and Commission International de L'Eclairage color coordinates (0.68, 0.32) at J = 1.5 mA cm−2, while the device with the CBP host shows maximum ηext = 12.1%. These high performances can be mainly explained by efficient triplet energy transfer from the host to the guests and improved charge balance attributable to the bipolar characteristics of the spirobifluorene group.

There has been growing interest in organic thin-film transistors (OTFTs) because of their potential applications in flexible, low-cost integrated circuits, such as smart cards, RF identification tags, and display backplanes, such as liquid crystal displays, electronic paper, and organic electroluminescent displays. [1,2] In particular, since organic semiconductors based on polymers and oligomers are attractive for their easy solution processing for film formation, recent research on OTFTs has been more focused on flexible electronic devices/display applications. Therefore, the most desired ultimate goal of organic semiconductor devices is to realize flexible electronics and displays that can be processed through all-solution processes including deposition of the active organic layers, the gate insulators, and the electrodes. Here we demonstrate all-solutionprocessed n-type organic transistors for the first time by depositing the source and drain metal by a spinning metal process.Despite the great interest and progress in organic and polymeric TFTs, most of the high field-effect-mobility OTFTs have been based on p-type channel materials. However, even if n-channel semiconducting materials are important for making ambipolar transistors [3,4] and complementary circuits, [5] they are relatively rare compared with the p-type materials. The reported field-effect mobilities of n-type OTFTs to date also show lower values than those of p-type devices. In addition, it has usually been observed that the solution-processed OTFTs show poorer performance than the vacuum-processed devices: for example, although the vacuum-evaporated pentacene transistor has shown high field-effect hole mobilities exceeding 1 cm 2 V ±1 s ±1 , [6] the solution-processed p-type transistor using the pentacene precursor showed low fieldeffect mobilities below 0.1 cm 2 V ±1 s ±1 . [7] Reports about the solution-processed n-type transistors are also relatively rare [5,8±10] and they usually show low charge-carrier mobilities (~10 ±2 cm 2 V ±1 s ±1 or less) [5,8,10,11] except that most recently the observation of a field-effect electron mobility as high as 0.1 cm 2 V ±1 s ±1 for a solution spin-coated conjugated ladder polymer was reported.[9] Here we report on solution-processed n-type OTFTs with high field-effect mobilities, based on the soluble derivatives of fullerene (C 60 ) as n-type channel materials. We obtained high field-effect electron mobilities of 0.02±0.1 cm 2 V ±1 s ±1 depending on the work-function of the source and drain metals, demonstrating that the electron injection current is contact-limited because of the Schottky barrier at the contact. Furthermore, we fabricated n-type OTFTs by an all-solution-deposition process including source and drain metals as well as gate insulators and organic semiconductors. These types of OTFTs are well suited for a wide range of existing and future flexible circuits and display applications that require a simplified production process and low-weight and low-cost products. In order to achieve the solu...

Noble Gemini surfactants containing a siloxane moiety have been designed and successfully synthesized in the present study and are utilized as structure-directing agents for mesoporous metal oxides such as zirconia, titania, and vanadia. The siloxane moiety is believed to play an important nano-propping role during the surfactant removal by direct calcination, yielding thermally stable mesoporous metal oxides. It is also believed that the synthesis strategy described here can be applied to the synthesis of robust nanostructured materials such as nanoparticles and nanorods in addition to mesoporous materials.