氧化锌(ZnO)是一种非常有前途的光电材料。然而,制备稳定的p-型ZnO一直是个技术难题,制约了相关器件的研发。正因如此,氮掺杂的ZnO引起了人们的重视。下面转载的在JACS上发表的这篇论文展示了这方面研究的最新进展。 --------------------------------------------------------- J Am Chem Soc. 2012 Jan 11;134(1):464-70. Epub 2011 Dec 8. P-type nitrogen-doped ZnO nanoparticles stable under ambient conditions. Chavillon B , Cario L , Renaud A , Tessier F , Cheviré F , Boujtita M , Pellegrin Y , Blart E , Smeigh A , Hammarstrm L , Odobel F , Jobic S . Source Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, UMR6502, 2 rue de la Houssinière, 44322 Nantes cedex 3, France. Abstract Zinc oxide is considered as a very promising material for optoelectronics. However, to date, the difficulty in producing stable p-type ZnO is a bottleneck, which hinders the advent of ZnO-based devices. In that context, nitrogen-doped zinc oxide receives much attention. However, numerous reviews report the controversial character of p-type conductivity in N-doped ZnO, and recent theoretical contributions explain that N-doping alone cannot lead to p-typeness in Zn-rich ZnO. We report here that the ammonolysis at low temperature of ZnO(2) yields pure wurtzite-type N-doped ZnO nanoparticles with an extraordinarily large amount of Zn vacancies (up to 20%). Electrochemical and transient spectroscopy studies demonstrate that these Zn-poor nanoparticles exhibit a p-type conductivity that is stable over more than 2 years under ambient conditions. 2011 American Chemical Society PMID:22092170
去年下半年的一点成果,本来可以深入继续搞下去的,可惜这边不做DSSC... 以前实验室的兄弟们告诉我,在改进若干条件后现在差不多做到6%了,在基于氧化锌 阳极材料的准固态DSSC里面,这个效率已经是世界前列了...可惜跟我没啥关系了,其实 做电池还是蛮好玩的... 期刊不算太好,被EES婉拒,诱惑说PCCP可以无审接受,实在是被投稿过程搞得太累,遂 从了。编辑有做奸商的潜力。所以有了“Received 6th April 2011, Accepted 7th April 2011”。 这个就是传说中的,瞬投瞬收。。。 不知道的还觉得很nx,其实。。。哎。。。人生啊,人生。。。 对于这个工作我对其中的想法还是蛮满意的,目前DSSC很多用氧化钛和氧化锌的纳米材料 作为阳极,通常有纳米颗粒,纳米线,以及各种多级结构。提高效率主要是从提高比表面积, 载流子传输速率,加强光散射三个方面入手。明显的纳米颗粒虽然比表面积大,但是不利于 载流子的传输;纳米线虽然提供了良好的导电通道,但是表面积又不太够;这里,我们一步 合成的多级结构(直接化学沉淀,无需劳什士高压釜,表面活性剂,常温常压家里面都可以 做)比表面积大,载流子传输系数是纳米颗粒的10倍,同时又可以作为良好的光散射中心, 无疑是一种优秀的DSSC光阳极材料。有兴趣的朋友可以follow一下哈,如果想合作做做可以 和俺以前的boss联系。另外求引用,呵呵。 http://pubs.rsc.org/en/content/articlelanding/2011/cp/c1cp21068h ZnO hierarchical structures for efficient quasi-solid dye-sensitized solar cells Chun Cheng, Yantao Shi, Chao Zhu, Wei Li, Lin Wang, Kwok Kwong Fung and Ning Wang Phys. Chem. Chem. Phys. , 2011, Advance Article DOI: 10.1039/C1CP21068H, Communication Abstract We report a direct precipitation method for mass production of ZnO microflowers (MFs) containing hierarchical structures. The ZnO MFs are constructed by interlaced single crystalline and porous nanosheets which are ideal photoanode material for dye-sensitized solar cells (DSCs) because the MFs can largely improve the energy harvesting performance and the efficiency of DSCs. Compared with other forms of nano-sized structures, the novel hierarchical structures show obvious advantages in DSC application because of their large surface area for dye-loading, good light scattering efficiency and excellent electrical transport property. The quasi-solid state DSCs fabricated with the MF hierarchical structures exhibited an efficiency of 4.12%, much higher than that of ZnO nanoparticle-based DSCs, indicating a great potential for the development of highly-efficient quasi-solid DSCs.
缺陷对氧化锌的光学、光电子学性能有着非常显著的影响。数十年来,ZnO可见发光的缺陷机制一直存在争议,缺乏统一的理论解释。 近年来,我们发展了具有局域瞬态极端条件的液相激光烧方法,并进行纳米颗粒的独特微结构相关的物性研究。在此基础上,获得了具有稳定较强蓝色发光的氧化锌纳米颗粒,进行了对缺陷发光机制的探索。一方面,研究了蓝色发光对激发波长依赖性。发现:1,蓝色发光存在几个固定的择优发射能量点;2,蓝色发光到绿色发光的转变,不是连续移动而是此消彼长的过程;3,蓝色发光的激发谱可以延伸到可见光波段,相应激发能量明显小于带隙宽度,并存在一系列子峰。另一方面,对相关缺陷进行了电子顺磁共振和正电子湮灭的研究。观察到间隙锌、空位氧、间隙锌复合缺陷、间隙氢在一定条件下的共存;随着蓝色发光到绿色发光的转换,间隙锌和空位氧在EPR谱中存在强烈相关的变化。此外,通过更细致的微结构控制,可见发光获得了一定称度上的调控。 该工作将有助于氧化锌可见发光的最终确立,推动相关基础研究与应用;同时也指出,相对于通常所注意的形貌、尺寸等,纳米材料的微结构控制对其性能具有及其重要的意义。相关论文发表在Adv. Funct. Mater. 2010, 20.561-572.上。该工作得到了国家自然科学基金的资助。 网络链接如下: http://www3.interscience.wiley.com/journal/123237358/abstract Blue Luminescence of ZnO Nanoparticles Based on Non-Equilibrium Processes: Defect Origins and Emission Controls By Haibo Zeng,* Guotao Duan, Yue Li, Shikuan Yang, Xiaoxia Xu, and Weiping Cai High concentrations of defects are introduced into nanoscale ZnO through non-equilibrium processes and resultant blue emissions are comprehensively analyzed, focusing on defect origins and broad controls. Some ZnO nanoparticles exhibit very strong blue emissions, the intensity of which first increase and then decrease with annealing. These visible emissions exhibit strong and interesting excitation dependences: 1) the optimal excitation energy for blue emissions is near the bandgap energy, but the effective excitation can obviously be lower, even 420nm (2.95 eVEg¼3.26 eV); in contrast, green emissions can be excited only by energies larger than the bandgap energy; and, 2) there are several fixed emitting wavelengths at 415, 440, 455 and 488nm in the blue wave band, which exhibit considerable stability in different excitation and annealing conditions. Mechanisms for blue emissions from ZnO are proposed with interstitial-zinc-related defect levels as initial states. EPR spectra reveal the predominance of interstitial zinc in asprepared samples, and the evolutions of coexisting interstitial zinc and oxygen vacancies with annealing. Furthermore, good controllability of visible emissions is achieved, including the co-emission of blue and green emissions and peak adjustment from blue to yellow. 氧化锌纳米颗粒的发光与激发光谱 建议的缺陷发光机制、可见发光调控 发表后记: 对这项工作与这篇文章颇有些感慨。 从工作的开始到发表历时是我至今最长的。这是在我博士工作基础上的继续,留所2年主要精力就花这上面了。当然,还有部分数据没发表。这是个科学问题探索型的基础研究,历程如下。随着对领域认识的不断加深,逐渐对领域内有哪些主要问题、研究状况有了自己的认识。慢慢的,有了解决其中一个(其实就目前潮流而言,是既不新也不热了)的冲动。随后就是独立设计方案,实施试验,进行分析。期间,少不了再学习、再调整、再实施。再后来,数据逐渐积累多了,就自然进入到思考与分析方面,体会数据,体会内涵,体会关联方面,真是所谓殚精竭虑!最后是,逐渐形成了一点自己的观点,就有加入了求证-再试验-分析的循环中。 相反,最后发表到好像没什么故事。本准备好被AFM拒稿后转投物理类IF稍低的杂志的,没想到很快收到的意见都较好,直接接受了。接受后,好像也没什么太高兴的。 自己评价:这是我至今比较好的工作,历史可能会证明观点是错误的,不过我也没什么遗憾的! 这个过程增加了我对科研,对科研中的自己的认识: 1, 认真做点科研,真是不容易!(反之,我的有些文章并没有这么辛苦) 2, 如果能认真做点科研,也不错啊。 3, 要边做边学边提高。 刚才看到关于这篇文章的报道出现在科学网论文栏的头条,有点吃惊。感谢编辑或者朋友的推荐。为了方便感兴趣的朋友的获取,特将文章的PDF文件附上。 文章的PDF文件