Benzothiadiazole Containing D‐π‐A Conjugated Compounds for Dye‐Sensitized Solar Cells: Synthesis,Properties, and Photovoltaic Performances

Two D ‐π‐A conjugated molecules, BzTCA and BzTMCA , were developed through facile synthetic approaches for dye‐sensitized solar cells. The investigation of the photophysical properties of BzTCA and BzTMCA both in dilute solutions and in thin films indicates that their absorption exhibits a wide coverage of the solar spectrum. The absorption features for BzTCA and BzTMCA commence at about 710 nm in solution, and at about 800 nm in the solid state. The absorption maxima (λ_max) for both BzTCA and BzTMCA on TiO₂ film are almost the same as those in dilute solution. Their HOMOs and LUMOs were found to partly overlap at the center of these dyes, which guarantees appreciable interactions between the donors and acceptors. The investigation of the performance of dye‐sensitized solar cells fabricated from BzTCA and BzTMCA indicated that the power‐conversion efficiencies are 6.04 % and 4.68 %, respectively, which could be comparable with the normal sensitizer N3. BzTMCA showed lower incident photon‐to‐electron conversion efficiency (IPCE) and J_sc values relative to BzTCA , which is probably because of the weaker driving force of dye regeneration and electron injection process of BzTMCA . The IPCE responsive area reached nearly 800 nm, which provides great potential for further improvement of the photocurrent density and power‐conversion efficiency. Our investigations demonstrate that both dyes BzTCA and BzTMCA could be promising candidates for dye‐sensitized solar cells.     

利用DPVBi的空穴阻挡和发光特性而制作的白光器件

介绍了结构为:ITO/m-MTDATA(40 nm)/NPB(5 nm)/DPVBi(10～12 nm)/Rubrene(0.5 nm)/DPVBi(20～18 nm)/Alq(50 nm)/LiF(0.5 nm)/Al的白光器件.该器件采用了两个DPVBi层中间夹一个Rubrene的薄层,这种结构充分利用了DPVBi的空穴阻挡特性和发光特性,有力地平衡了来自于DPVBi的蓝光、Alq的绿光和Rubrene的黄光,从而使器件发射性能较好的白光.当第一层的DPVBi和第二层的DPVBi的厚度分别是11 nm和19 nm时,其他层的厚度保持不变,该器件在15 V电压下,最大亮度为11 290 cd/m2 ,对应的效率为1.71 cd/A,色坐标为(0.25,0.27),属于白光发射;在6 V时,其最大效率为3.18 cd/A.     

Chemical locomotion

Research into the autonomous motion of artificial nano- and microscale objects provides basic principles to explore possible applications, such as self-assembly of superstructures, roving sensors, and drug delivery. Although the systems described have unique propulsion mechanisms, motility in each case is made possible by the conversion of locally available chemical energy into mechanical energy. The use of catalysts onboard can afford nondissipative systems that are capable of directed motion. Key to the design of nano- and micromotors is the asymmetric placement of the catalyst: its placement in an environment containing a suitable substrate translates into non-uniform consumption of the substrate and distribution of reaction products, which results in the motility of the object. These same principles are exploited in nature to effect autonomous motion.     

Fabrication approaches to ZnO nanowire devices

To date, most of the work on ZnO nanostructures has focused on the synthesis methods and there have been only a few reports of the electrical characteristics. We report on fabrication methods for obtaining device functionality from single ZnO nanorods. A key aspect is the use of sonication to facilitate transfer of the nanorods from the initial substrate on which they are grown to another substrate for device fabrication. Examples of devices fabricated using this method are briefly described, including metal-oxide semiconductor field effect depletion-mode transistors with good saturation behavior, a threshold voltage of ∼−3 V, and a maximum transconductance of order 0.3 mS/mm and Pt Schottky diodes with excellent ideality factors of 1.1 at 25°C and very low (1.5×10⁻¹⁰ A, equivalent to 2.35 Acm⁻², at −10 V) reverse currents. The photoresponse showed only a minor component with long decay times (tens of seconds) thought to originate from surface states. These results show the ability to manipulate the electron transport in nanoscale ZnO devices.     

优化小型显示器

集成器件综合了先前独立产品的一些功能，代表了可移动电子产品的未来，并且正在推动小型显示器领域激发的技术发展。     

Electrical aspects of photovoltaic devices based on bi-layer organic semiconducting materials

Here we have investigated the opto-electrical properties of bi-layer sandwich devices based on polymer/C₆₀ hetero junctions. In this type of device the polymer acts as an electron donor to the second layers the C₆₀ which plays the role of an electron acceptor.     

Electrochromic properties as a function of electrolyte on the performance of electrochromic devices consisting of a single-layer polymer

Herein, a study on varying salts and their composition used in the gel electrolyte for a one-step lamination assembly procedure for electrochromic devices was carried out to explore their effects on various electrochromic performance parameters, such as color uniformity, photopic contrast, switching speed, and optical memory. Electrochromic polymers formed in different gel electrolyte compositions are highly dependent on the type, amount, and composition of salt used. The following groups of salts were investigated: ionic liquids, ammonium salts, and lithium salts. The lithium salts yielded devices with the best color uniformity, photopic contrast as high as 48%, and switching response speeds as low as 1 s for 5.5 cm² devices using the electroactive monomer 2,2-dimethyl-3,4-propylenedioxythiophene (ProDOT-Me₂) to generate the electrochromic polymer. Hermetically sealed electrochromic devices exhibited optical memory of 27 h for a 2% photopic transmittance loss under normal laboratory conditions, and a 171 cm² electrochromic device was demonstrated.