http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Hong, Jisu,Sung, Min Jae,Cha, Hyojung,Park, Chan Eon,Durrant, James R.,An, Tae Kyu,Kim, Yun-Hi,Kwon, Soon-Ki American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.42
<P>To investigate the influence of donor molecule crystallinity on photovoltaic performance in all-small-molecule solar cells, two dithieno[2,3-<I>d</I>:2′,3′-<I>d</I>′]-benzo[1,2-<I>b</I>:4,5-<I>b</I>′]dithiophene (DTBDT)-based small molecules, denoted as DTBDT-Rho and DTBDT-S-Rho and incorporating different side chains, are synthesized and characterized. The photovoltaic properties of solar cells made of these DTBDT-based donor molecules are systemically studied with the [6,6]-phenyl-C<SUB>71</SUB>-butyric acid methyl ester (PC<SUB>71</SUB>BM) fullerene acceptor and the O-IDTBR nonfullerene acceptor to study the aggregation behavior and crystallinity of the donor molecules in both blends. Morphological analyses and a charge carrier dynamics study are carried out simultaneously to derive structure-property relationships and address the requirements of all-small-molecule solar cells. This study reveals exciton decay loss driven by large-scale phase separation of the DTBDT molecules to be a crucial factor limiting photocurrent generation in the all-small-molecule solar cells incorporating O-IDTBR. In the all-small-molecule blends, DTBDT domains with dimensions greater than 100 nm limit the exciton migration to the donor-acceptor interface, whereas blends with PC<SUB>71</SUB>BM exhibit homogeneous phase separation with smaller domains than in the O-IDTBR blends. The significant energy losses in nonfullerene-based devices lead to decreased <I>J</I><SUB>sc</SUB> and fill factor values and unusual decrease in <I>V</I><SUB>oc</SUB> values. These results indicate the modulation of phase separation to be important for improving the photovoltaic performances of all-small-molecule blends. In addition, the enhanced molecular aggregation of DTBDT-S-Rho with the alkylthio side chain leads to higher degrees of phase separation and unfavorable charge transfer, which are mainly responsible for the relatively low photocurrent when using DTBDT-S-Rho compared with that when using DTBDT-Rho. On the other hand, this enhanced molecular aggregation improves the crystallinity of DTBDT-S-Rho and results in its increased hole mobility.</P> [FIG OMISSION]</BR>
Li, Xiaoe,Nazeeruddin, Mohammad K.,Thelakkat, Mukundan,Barnes, Piers R. F.,Vilar, Ramó,n,Durrant, James R. The Royal Society of Chemistry 2011 Physical chemistry chemical physics Vol.13 No.4
<P>We report the application of spectroelectrochemical techniques to compare the hole percolation dynamics of molecular networks of two ruthenium bipyridyl complexes adsorbed onto mesoporous, nanocrystalline TiO<SUB>2</SUB> films. The percolation dynamics of the ruthenium complex <I>cis</I>-di(thiocyanato)(2,2′-bipyridyl-4,4′-dicarboxylic acid)-(2,2′-bipyridyl-4,4′-tridecyl) ruthenium(<SMALL>II</SMALL>), N621, is compared with those observed for an analogous dye with an additional tri-phenyl amine (TPA) donor moiety, <I>cis</I>-di(thiocyanato)(2,2′-bipyridyl-4,4′-dicarboxylic acid)-(2,2′-bipyridyl-4,4′-bis(vinyltriphenylamine)) ruthenium(<SMALL>II</SMALL>), HW456. The <I>in situ</I>oxidation of these ruthenium complexes adsorbed to the TiO<SUB>2</SUB> films is monitored by cyclic voltammetry and voltabsorptometry, whilst the dynamics of hole (cation) percolation between adsorbed ruthenium complexes is monitored by potentiometric spectroelectrochemistry and chronoabsorptometry. The hole diffusion coefficient, <I>D</I><SUB>eff</SUB>, is shown to be dependent on the dye loading on the nanocrystalline TiO<SUB>2</SUB> film, with a threshold observed at ∼60% monolayer surface coverage for both dyes. The hole diffusion coefficient of HW456 is estimated to be 2.6 × 10<SUP>−8</SUP> cm<SUP>2</SUP>/s, 20-fold higher than that obtained for the control N621, attributed to stronger electronic coupling between the TPA moieties of HW456 accelerating the hole percolation dynamics. The presence of mercuric ions, previously shown to bind to the thiocyanates of analogous ruthenium complexes, resulted in a quenching of the hole percolation for N621/TiO<SUB>2</SUB> films and an enhancement for HW456/TiO<SUB>2</SUB> films. These results strongly suggest that the hole percolation pathway is along the overlapped neighbouring -NCS groups for the N621 molecules, whereas in HW456 molecules cation percolation proceeds between intermolecular TPA ligands. These results are discussed in the context of their relevance to the process of dyeregeneration in dye sensitised solar cells, and to the molecular wiring of wide bandgap inorganic materials for battery and sensing applications.</P> <P>Graphic Abstract</P><P>We employ spectroelectrochemical techniques to compare the hole percolation dynamics of two ruthenium bipyridyl complexes adsorbed onto mesoporous TiO<SUB>2</SUB> films. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0cp01013h'> </P>
Sorcar, Saurav,Thompson, Jamie,Hwang, Yunju,Park, Young Ho,Majima, Tetsuro,Grimes, Craig A.,Durrant, James R.,In, Su-Il The Royal Society of Chemistry 2018 Energy & environmental science Vol.11 No.11
<P>The production of solar fuels offers a viable pathway for reducing atmospheric CO2 concentrations and the storage and transport of solar energy. While photoconversion of CO2 into C1 hydrocarbon products, notably methane (CH4), is known, the ability to directly achieve significant quantities of higher-order hydrocarbons represents an important step towards practical implementation of solar fuel technologies. We describe an efficient, stable, and readily synthesized CO2-reduction photocatalyst, Pt-sensitized graphene-wrapped defect-induced blue-coloured titania, that produces a record high combined photocatalytic yield of ethane (C2H6) and methane. For the first time, a systematic ultraviolet photoelectron spectroscopy study on the mechanism underlying ethane formation indicates that the process is dependent upon upward band bending at the reduced blue-titania/graphene interface. Furthermore, transient absorption spectroscopy indicates photogenerated holes move into the graphene while electrons accumulate on the Ti<SUP>3+</SUP> sites, a phenomenon contradicting prior assumptions that graphene acts as an electron extractor. We find that both mechanisms serve to enhance multielectron transfer processes that generate ˙CH3. Utilizing a continuous flow-through (CO2, H2O) photoreactor, over the course of multiple 7 h runs approximate totals of 77 μmol g<SUP>−1</SUP> C2H6 and 259 μmol g<SUP>−1</SUP> CH4 are obtained under one sun AM 1.5G illumination. The photocatalyst exhibits an apparent quantum yield of 7.9%, 5.2% CH4 and 2.7% C2H6, and stable photocatalytic performance over the test duration of 42 h. The carbon source for both products is verified using <SUP>13</SUP>CO2 isotopic experiments.</P>
Ming Hao Jin,Eunhye Shin,Saera Jin,Hongil Jo,Kang Min Ok,Jongin Hong,Byung-Hyuk Jun,James R. Durrant 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.5
Cubic BaTiO3 (C-BT) and tetragonal BaTiO3 (T1-BT) nanoparticles were prepared by a solvothermal method with controlling the Ba/Ti precursor ratio. Triethanolamine was additionally employed in the synthesis to obtain ferroelectric BaTiO3 with improved particle size distribution and tetragonality (T2-BT). The prepared nanoparticles were thoroughly characterized by scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller analysis, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, photoluminescence, and second-harmonic generation. Importantly, the BaTiO3 nanoparticles were introduced into the scattering layer of dye-sensitized solar cells and T2-BT showed better power conversion eciency than C-BT and T1-BT.
Hong, Jisu,Ha, Yeon Hee,Cha, Hyojung,Kim, Ran,Kim, Yu Jin,Park, Chan Eon,Durrant, James R.,Kwon, Soon-Ki,An, Tae Kyu,Kim, Yun-Hi American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.51
<P>A series of naphthalene diimide (NDI)-based small molecules were synthesized as nonfullerene acceptors and incorporated in all-small-molecule solar cells. Three NDI-based small molecules, NDICN-T, NDICN-BT, and NDICN-TVT, were designed with different linkers between two NDI units to induce the different conjugation length and modulate the geometric structures of the NDI dimers. The small NDI-based dimer electron acceptors with slip-stacked structures that facilitate pi-pi stacking interactions and/or hinder excessive aggregation exhibited different morphological behaviors, such as miscibility or crystallinity in bulk heterojunction blends with 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-bldithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bi-thiophen]-5-y1)benzo[c][1,2,5]thiadiazole) (DTS-F) electron donors. The photovoltaic devices prepared with NDICN-TVT gave the highest power conversion efficiency (PCE) of 3.01%, with an open-circuit voltage (V-oc) of 0.75 V, a short-circuit current density (J(sc)) of 7.10 mA cm(-2), and a fill factor of 56.2%, whereas the DTS-F:NDICN-T and DTS-F:NDICN-BT devices provided PCEs of 1.81 and 0.13%, respectively. Studies of the charge-generation properties, charge-transfer dynamics, and charge-transport properties for understanding the structure-property relations revealed that DTS-F:NDICN-TVT blend films with well developed domains and well-ordered crystalline structures performed well, whereas an excessive miscibility between DTS-F and NDICN-BT disrupted the crystallinity of the material and yielded a poor device performance.</P>
Du, Tian,Xu, Weidong,Daboczi, Matyas,Kim, Jinhyun,Xu, Shengda,Lin, Chieh-Ting,Kang, Hongkyu,Lee, Kwanghee,Heeney, Martin J.,Kim, Ji-Seon,Durrant, James R.,McLachlan, Martyn A. The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.32
<P>Doping is a widely implemented strategy for enhancing the inherent electronic properties of charge transport layers in photovoltaic (PV) devices. Here, in direct contrast to existing understanding, we find that a reduction in p-doping of the organic hole transport layer (HTL) leads to substantial improvements in PV performance in planar p-i-n perovskite solar cells (PSCs), driven by improvements in open circuit voltage (<I>V</I>OC). Employing a range of transient and steady state characterisation tools, we find that the improvements of <I>V</I>OC correlate with reduced surface recombination losses in less p-doped HTLs. A simple device model including screening of bulk electric fields in the perovskite layer is used to explain this observation. In particular, photoluminescence (PL) emission of complete solar cells shows that efficient performance is correlated to a high PL intensity at open circuit and a low PL intensity at short circuit. We conclude that desirable transport layers for p-i-n PSCs should be charge selective contacts with low doping densities.</P>