Performance Improvement of Bulk Heterojunction Organic Photovoltaic Cell by Addition of a Hole Transport Material

A novel photovoltaic cell with an active layer of poly（phenyleneethynylene） （PPE）/C60/N,N＇-diphenyl-N,N＇-di-（m-tolyl）-p-benzidine （TPD） is designed. In the active layer, PPE is the major component; C60 and TPD are the minor ones. Compared with a control BHJ device based on PPE/C60, the short circuit current density Jsc is increased by 1 order of magnitude, and the whole device performance is increased greatly, however the open circuit voltage Voc is largely decreased. The possible mechanism of the improved performance may be as follows： In the PPE/C60/TPD device, PPE, C60, and TPD serve as the energy harvesting material, the electron transport material, and the hole transport material, respectively. As the TPD and C60 are spatially separated by PPE, the charge recombination is effectively retarded.

The preparation of functionalized single walled carbon nanotubes as high efficiency DNA carriers

The positively charged single walled carbon nanotubes （SWNTs^＋） were prepared by conjugating with -CONH-C6H12-NH3^＋. The double strand DNA （dsDNA） chains were loaded onto SWNTs^＋ via the electrostatic interactions. SWNTs^＋ shows improved loading efficiency （353.5 μg/mg） toward dsDNA compared with that of charged free single walled carbon nanotubes （SWNTs） （82.9 μg/mg）.

CHEMICAL DERIVATION OF HUMAN INSULIN SUPERAGONISM

The role of three highly conserved insulin residues Tyr^B26 was studied to better understand the relationship between insulin and receptor from rat adipose tissue plasma membranes, lnsulin analogues with a single amino acid substitution or single N-methylation of the peptide bond in the position B26 were all shortened in the C-terminus of the B-chain by four amino acids. The effect of modifications was followed by the binding to the insulin receptor. From our results, we can deduce several conclusions： （1） the replacement of tyrosine in the position B26 by histidine, [N-MeHis^B26]-des-tetrapeptide-（B27-B30）-insulin-B26-amide and [N-MeGlu^B26]-des-tetrapeptide- （B2-B30）-insulin-B26-amide, have no significant effect on the binding affinity and they show binding affinity 105%, 190% and 208%, respectively, of that of human insulin; （2） [Aad^B26] -des-tetrapeptide-（B27-B30）-insulin-B26-amide and [Phe（4-carboxy^B26）]-des-tetrapeptide- （B27~B30）-insulin-B26-amide affect the potency highly positively in vitro studies; they show binding affinity 529 and 289 %, respectively, of that of human insulin.

Solution-processable graphene mesh transparent electrodes for organic solar cells

Graphene mesh electrodes （GMEs） with good conductivity and transparency have been fabricated by the standard industrial photolithography and 02 plasma etching process using graphene solutions. Organic photovoltaic （OPV） cells using GMEs as the transparent electrodes with a blend of poly-（3-hexylthiophene） phenyl-C61-butyric acid methyl ester （P3HT/PC61BM） as the active layer have been fabricated and exhibit a power conversion efficiency （PCE） of 2.04%, the highest PCE for solution-processed graphene transparent electrode-based solar cells reported to date.

Synthesis and properties of copolymers based on 5,6-dinitrobenzothiadiazole with low band gap and broad absorption spectra

One polythiophene derivative PT3T and two low band gap copolymers,PBTT-T3T and PBTT,with different ratios of 5,6-dini-trobenzothiadiazole as the acceptor unit in the polymer backbone have been synthesized by Pd-catalyzed Stille-coupling polymerizations.Thermal stability,X-ray diffraction analyses,UV-vis absorption spectra,photoluminescence spectra and electrochemical properties of the copolymers were investigated.The band gap estimated from UV-vis-NIR spectra of the copolymers films varied from 1.39 to 1.94 eV.Among these copolymers,the films of PBTT-T3T and PBTT,which contain the 5,6-dinitrobenzothiadiazole unit,cover a broad wavelength range in the visible and near-infrared region from 400 to 1000 nm with the maximal peak absorption around 700 nm,which is exactly matched with the maximum in the photon flux of the sun.

Dithienopyrrole Based Small Molecule with Low Band Gap for Organic Solar Cells

A low band gap acceptor-donor-acceptor （A-D-A） small molecule donor material, named DR3TDTN, has been designed and synthesized for solution-processed organic solar cells. DR3TDTN shows narrow optical band gap with value of 1.49 eV and broad absorption spectrum from 300 to 820 rim. The HOMO and LUMO energy levels of DR3TDTN are -4.74 and -3.26 eV, respectively. The optimized photovoltaic device based on DR3TDTN：PC71BM blend film shows a power conversion efficiency of 3.03% with an open-circuit voltage of 0.67 V, a short-circuit current of 8.22 mA·cm^-2 and fill factor of 0.55.

Manipulating active layer morphology of molecular donor/polymer acceptor based organic solar cells through ternary blends

The development of molecular donor/polymer acceptor blend(MD/PA)-type organic solar cells(OSCs) lags far behind other type OSCs. It is due to the large-size phase separation morphology of MD/PAblend, which results from the high crystallinity of molecular donors. In this article, to suppress the crystallinity of molecular donors, we use ternary blends to develop OSCs based on one polymer acceptor(P-BNBP-f BT) and two molecular donors(DR3 TBDTT and BTR) with similar chemical structures.The ternary OSC exhibits a power conversion efficiency(PCE) of 4.85%, which is higher than those of the binary OSCs(PCE=3.60% or 3.86%). To our best knowledge, it is the first report of ternary MD/PA-type OSCs and this PCE is among the highest for MD/PA-type OSCs reported so far. Compared with the binary blends, the ternary blend exhibits decreased crystalline size and improved face-on orientation of the donors. As a result, the ternary blend exhibits improved and balanced charge mobilities, suppressed charge recombination and increased donor/acceptor interfacial areas, which leads to the higher shortcircuit current density. These results suggest that using ternary blend is an effective strategy to manipulate active layer morphology and enhance photovoltaic performance of MD/PA-type OSCs.

Hybrid Material of Graphene and Poly(3,4-ethyldioxythiophene)with High Conductivity,Flexibility,and Transparency

A novel hybrid material prepared from graphene and poly(3,4-ethyldioxythiophene)(PEDOT)shows excellent transparency,electrical conductivity,and good flexibility,together with high thermal stability and is easily processed in both water and organic solvents.Conductivities of the order of 0.2 S/cm and light transmittance of greater than 80%in the 4001800 nm wavelength range were observed for fi lms with thickness of tens of nm.Practical applications in a variety of optoelectronic devices are thus expected for this transparent and flexible conducting graphene-based hybrid material。

Bromination of Isothianaphthene Derivatives towards the Application in Organic Electronics

Different approaches to brominate dialkyl isothianaphthene-5,6-dicarboxylate were tried and single crystals of target molecule and side product were obtained. A planar copolymer with the trans-ethene has been prepared, which shows good solubility in common organic solvents and broad absorption with edge to 967 nm in film.

Rubbery neat carbon aerogels

Polymeric elastomers possess unique elastic mechanical properties that set them apart from other materials,and enable wide applications in a large variety of products such as elastic films,foams and tires.The polymer chains tend to be coil-like due to thermal fluctuation but can also be straightened by external forces,leading to large reversible deformations.