| It has been two hundreds years that organic materials were firstly discovered and recognized by human beings. As early as 1806, J. J. Berzelius, a Swedish chemist, who initially proposed a notion about organic compound. Then, the notion of the organic compound was developed to abiotic carbon materials since the artificial urea was successfully synthesized. Afterwards, scientists, especially the chemists paid more attention to synthesis organic compounds. Long chain polymer, rubber, vulcanized rubber and celluoid plastics have been obtained under the strenuous exploration of many scientists. In addition, further research on organic materials has been carried out with the appearance of many new organic materials. Decades later, organic crystalline materials and nonlinear optical properties began to attract a lot of researchers’interests; In 1977, J. A. Heeger was honored Nobel prize due to their pioneering work on conductive polymer materials. They pointed out that the necessary conditions for the conductive polymer is% conjugate structure of alternating single and double bonds between carbons; In 1988, Fert A and Gruenberg P wined the 2007’s Nobel prize for their distinguish contributions on giant magnetoresistance effect (GMR), then the high sensitivity of magnetic sensor has been successfully applied to hard disk read head on the enlightenment of the GMR effect, which greatly further the progress of science and technology and people’s life; In the year of 2002, Dediu and his works observed that the spin polarized electrons could be injected into organic semiconductors. Two years later, Xiong et al successfully fabricated Alq3 spin valve with "sandwich" device structure and 40% magnetoresistance was observed in 11K. Whereafter, giving birth to a new cross-discipline of organic spintronics with the utilization of organic materials in spintronics.As we all know, electron has two intrinsic properties that are charge and spin. Organic spintronics aims to utilize the two intrinsic properties simultaneously. The devices have high performances such as higher density storage of data, operation speed, low turn on voltage and power dissipation and nonvolatile. Why organic, advantages? Firstly, diversity, inexpensive, flexibility, modify and various functions; Secondly, organic materials have weak spin-orbit coupling and hyper-fine interactions, extremely long spin relaxation time and long diffusion length. Therefore, organic semiconductors have outstanding and irreplaceable role in spintronics than their counterparts. However, there still exist great disputes about the intrinsic transport of polarized electrons in organic semiconductors.From 1996 and then on, fullerene, carbon nanotubes (CNT) and 2D fullerene were discovered, and the performances of the three materials exhibit a great relationship with the structures, dimension and shape. In the past decade, a lot of exploration work have been done on nanostructures and shape of organic semiconductors, including nanodots, nanorods, nanowires and nanotubes, which exhibit the quantum confinement effects in the other dimensions. Nanomaterials with 1D coherence are more suitable for the construction of active nanodevices and interconnects rather than OD amorphous nanoparticles. Inorganic 1D nanomaterials have been widely investigated and widely used as building blocks in many kinds of optoelectronic integrations, and it is very reasonable to assume that their organic counterparts can also play an important role in this field. During the past ten years, organic 1D nanomaterials constructed from small functional molecules have obtained more and more attention due to their unique optical and electronic properties as well as their potential applications in nanoscale devices. For example,1) To date, the performances of inorganic devices maybe meet a bottleneck or limitation. It is impossible to further functions and diminish the scale of the devices as the Moore’s law because of the quantum tunneling; 2) Compared with inorganic materials, organic semiconductors have broad categories, importantly, the functions can be well manipulated by graft and chemical modify; 3) Organic materials have the merits of low weight, flexibility, soft and processibility. Therefore, it is easy to fabricate portable devices and large scale printing; 4) Organic materials can not only achieve the functions of their counterparts, also have their own peculiar performances, which can extend or supplement the shortcoming of the inorganic devices; 5) Finally, organic materials have excellent compatibility with organism. Accompanying the vigorous growth of nanoscience and nanotechnology, organic materials will have a bright future in life science and modern medicine.Bottom-up nanotechnology has entered a new decade toward the multiscale self-assembly of materials from the molecular or nanostructure level upwards, while advancing knowledge about biological processes and biophysicochemical interactions. A large number of studies on organic nanotubes have focused on the molecular design of building blocks and their material function, there has been little research that has addressed the function of the nanochannels themselves, such as their encapsulation ability. The dimensions of self-assembled organic nanotubes (S-ONTs) are well compatible with those of diverse nanostructures, including proteins, organic, inorganic or metal nanoparticles, dendrimers, viruses and DNAs. S-ONTs can give rise to a novel research field of mesoscale host-guest science and engineering. Focusing on the distinctive function and structural characteristics of these nanochannels, herein we stress that the research on the unique properties of nanochannels that can encapsulate, transport and release biomacromolecules as well as exert a confinement effect on water is a promising research interest. According to the best of our knowledge, there is no report on the tubular nanstructures of Alq3 and Gaq3 materials. Especially Gaq3 has finished phase I trials with the outcome of promising tolerability and evidence of clinical activity in renal cell carcinoma. Therefore, there is urgent need to critically evaluate and fabricate Gaq3 tubular with loading capacity as a lead-drug candidate.Herein, we use 8-hydroxyquinoline aluminum (Alq3) and 8-hydroxyquinoline gallium (Gaq3) to fabricate OD and 1D nanostructures by PVD and self-assembly methods, respectively. Up to now, to our knowledge, tubular nanostructures of these two materials are firstly obtained. In addition, the photoelectrical properties were also investigated. The detailed contents and key results are listed as follows:1. The fabrication and properties of single-crystal ε-Alq3 obtained by PVDHigh quality s-Alq3 crystals were prepared by using PVD method. The unit cell parameters by XSCD were a=13.548(2) A,6=15.880(3) A, c=18.734(3) A, α=95.507(2)°,β=109.735(2)°, γ=114.801(2)°, volume=3308.01 A3 and Z=6. The crystals have pine needle-like structures with the sizes of the needles about 10×10× 300 μm3. We attributed the good quality to the low growth rate and the weak perturbation in the process of crystal growth. Large straight steps with fixed step widths were observed from the side face of the crystals. The PL spectra of the Alq3 crystals at different temperatures were measured and the crystals show green mission with the PL peaks at 519 nm (2.39 eV). The optical band gap of ε-Alq3 crystal is about 2.82 eV.2. Simultaneous emissions of red, green and blue from pure tris(8-hydroxyquinoline) aluminum (Alq3) nanoparticles prepared by an extremely facile solution methodWe have prepared a rice-like Alq3 nanomaterial through a very facile solution method. The size of the nanoparticles can be controlled by adjusting the concentration of the Alq3 solution. The PL spectra of the rice-like Alq3 particles are composed of three broad emission peaks with their maxima at 410 nm (3.0 eV),518 nm (2.4eV) and 690 nm (1.8eV), respectively. The simultaneous emissions of R, G and B from un-doped rice-like Alq3 nanoparticles may facilitate the fabrication of white-OLED with low fabrication cost and high stability.3. Flexible single-crystal Alq3 microtubes and their exceptional waveguide propertiesWe firstly report an extremely facile strategy to fabricate Alq3 mircotubes with wall thickness at nanoscale, regular hexagonal shape, excellent flexibility and single crystal structures. The possible formation mechanism of the Alq3 microtubes has been emphatically discussed refer to the temporal evolution of SEM morphology by successfully controlling the solution concentration of Alq3. Furthermore, the as-prepared microtubes have outstanding waveguide properties, which allows them to find potential applications in novel optical and optoelectronic devices. In addition, this controllable growth mechanism is highly transferable to synthesizing other organic low-weight molecules with desired shapes and nanostructures.4. The fabrication and properties of crystalline Gaq3 microrods obtained by PVDThe crystalline Gaq3 microtubes with regular hexagonal cross section were firstly obtained by PVD method. The a-Gaq3 sample with mer isomer, which was identified by PXRD. The length of the longest rod can reach 400 μm, the diameter is 9 μm and aspect ratio of length/diameter (L/D ratio) of about 44. The obtained samples have regular shape and high crystalline due to we overcome the perturbation during the growth process as possible. The broad peak show a good symmetry in the range of 450 nm to 650 nm, the calculated CIE coordinates of the PL spectra at is (0.268,0.535), which exhibits green emission.5. The controllable fabrication and properties of Gaq3 micro/nanotubesWe have successfully synthesized Gaq3 sub-microtubes with wall thickness at the nanoscale by using an extremely facile solution approach. Formation of these sub-microtubes is accomplished through self-assembling, which is controllable by adjusting experiment condition. Furthermore, this new type of structures possess comparable optical properties to other nanostructures, but they have a greater tunability and a bigger surface-volume ratio, allowing them particularly useful for optoelectronic and pharmaceutical applications. In particular, device based on these new tubular structures exhibits outstanding field emission performance, mostly evident from a relatively low turn-on voltage but a very high maximum current density. This controllable growth mechanism is highly transferrable to growing other organic nanomaterials with desired shapes and structures. In addition, growth of a nanoscale tubular structure of an anticancer drug that holds simultaneously the roles of "nanocarrier" and "anticancer" significantly advances the pharmaceutical applications of this type of drugs. |
PDF Full Text Request