| Hierarchical micro-nano structures have larger surface areas and complicate morphologies. These structures greatly increase the light absorption in the photoelectrical devices such asphotovoltaic. At the same time, the nanostructures largely enhance the electronseparation efficiency. Recently, lots of methods for the preparation of micro/nano structures have been reported, such as wet solution method, hard template method,photolithography, sol-gel and electrospinning method.However, it is still difficult to find a way for low-cost, high-quality and facile preparations. In nature, there are many natural micro-nano structures with unique functional properties, such as butterfly wings, diatom shell,lotus leaves, spidersilks and rosepetals. Recently, Jiang et alstudied the micro-nano hierarchical structure and superhydrophobic surfaces and high adhesion properties of fresh roses and discovered the "petal effect". Biomimetic fabrication of micro-nano structures had been inspired by simply duplicating natural petal surface structure to get high-quality micro-nano hierarchical structures. With direct bandgap of 3.37 e V and 60 me Vexaction bound energy, Zn O is a promising material for the production of optoelectronic devices.Especially the one-dimensional Zn O structures, with high surface area and the Debye length,show superior light sensitivity and high-efficient electron separation properties. In this thesis,we have combined the unique surface structures of rose petals with Zn O nanostructure to explore the impact of hierarchicalmicro-nanostructures tothe surfacewetting and optoelectronic properties of Zn O composite materials. Finally, we try toprepare superhydrophobic, self-cleaning and optoelectronic functional materials with high light response. According to these ideas, we carried out the following studies:(1) The assembly of Zn O nanostructures on rose petals: We assembled Zn O nanostructures on the surface of natural rose petals usinglow temperature hydrothermalmethod. By changing the hydrothermal growth factors, different morphologies and structures of crystalline Zn O nanostructures wereprepared on the rose petal. The assembled Zn O nanostructures and dehydration phenomenon of rose petal make the superhydrophobic surface and high adhesion properties of rose petals disappeared. I-V tests showed that assembled Zn O nanostructures on rose petals has a 200 times of response to ultraviolet light.(2) The duplication of PDMS stamps from rose petal and growth of Zn O nanostructure onrose-petal-like PDMS: Rose-petal-like PDMS was prepared by a two-step replication method. These flexible PDMS can be used as substrates with high, transparency for the growth of Zn O micro-nano structures. By the combination of magnetron sputtering Zn O seed layer and the subsequent hydrothermal grown of Zn O nanostructures on PDMS, we obtained a series of crystallized Zn O nanostructures with different morphologies and structures. The assembled Zn O nanostructuresincrease the superhydrophobic performance of PDMS surface with a contact angle of 164 ° and self-cleaning property. To explore the response to ultraviolet light of Zn O / PDMS micro-nano hierarchical structure and its applications of photovoltaic under UV irradiation, some simple Zn O / PDMS deviceswere assembled and tested.Its photocurrent / dark current response is about 1000 times.It can be used for the fabrication of flexible transparent UV detectors.(3) The Preparation of Zn O micro-nano structures and Sn O2 / Zn O composite structures: Using negative PDMS as a template, Zn O and Sn O2 thin films with rose petal surface structureswere assembledby sol-gel method and nano-imprint technology. Zn O and Sn O2 / Zn O micro / nano structures were fabricated with various morphologies and structures by further hydrothermal growth. I-V tests showed UV response in a 103 magnitude. |
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