Panchromatic photon-harvesting by hole-conducting materials in inorganic-organic heterojunction sensitized-solar cell through the formation of nanostructured electron channels.

Additional photon-harvesting by hole transporting materials in Sb(2)S(3)-sensitized solar cell is demonstrated through the formation of electron channels in the hole transporter such as P3HT (poly(3-hexylthiophene)) and PCPDTBT(poly(2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)) that can act as both a hole conductor and light absorber. As a result, the short-circuit current density is improved with an increment in overall efficiency. These findings provide new insights into use of light-absorbing conjugated polymers as a hole conductor in the inorganic-organic heterojunction sensitized solar cells.

Enhancing the device performance of Sb2S3-sensitized heterojunction solar cells by embedding Au nanoparticles in the hole-conducting polymer layer.

Performance of Sb(2)S(3)-sensitized heterojunction solar cells is enhanced by embedding Au nanoparticles in the poly-3-hexylthiophene (P3HT) hole-conducting polymer layer. The improved charge transfer/transport at the Sb(2)S(3)/P3HT/Au interface by extended interface area of the P3HT/Au counter electrode and the re-absorption of the backscattering light from the embedded Au nanoparticles enhanced the device performance: J(sc) 11.0 to 12.8 mA cm(-2), V(oc) 606 to 626 mV, fill factor (FF) 60.5 to 61.2%, and power conversion efficiency (η) 4.0 to 4.9%. Simultaneous enhancement of V(oc), J(sc), and FF in Au nanoparticle-embedded systems is mainly attributed to the improved charge collection efficiency and light harvesting efficiency of Sb(2)S(3) due to the improved charge transfer/transport in the Sb(2)S(3)/P3HT/Au interface.

Toward interaction of sensitizer and functional moieties in hole-transporting materials for efficient semiconductor-sensitized solar cells.

Sb(2)S(3)-sensitized mesoporous-TiO(2) solar cells using several conjugated polymers as hole-transporting materials (HTMs) are fabricated. We found that the cell performance was strongly correlated with the chemical interaction at the interface of Sb(2)S(3) as sensitizer and the HTMs through the thiophene moieties, which led to a higher fill factor (FF), open-circuit voltage (V(oc)), and short-circuit current density (J(sc)). With the application of PCPDTBT (poly(2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)) as a HTM in a Sb(2)S(3)-sensitized solar cell, overall power conversion efficiencies of 6.18, 6.57, and 6.53% at 100, 50, and 10% solar irradiation, respectively, were achieved with a metal mask.

High-performance nanostructured inorganic-organic heterojunction solar cells.

We report all solid-state nanostructured inorganic-organic heterojunction solar cells fabricated by depositing Sb(2)S(3) and poly(3-hexylthiophene) (P3HT) on the surface of a mesoporous TiO(2) layer, where Sb(2)S(3) acts as an absorbing semiconductor and P3HT acts as both a hole conductor and light absorber. These inorganic-organic light harvesters perform remarkably well with a maximum incident-photon-to-current efficiency (IPCE) of 80% and power conversion efficiency of 5.13% under air-mass 1.5 global (AM 1.5G) illumination with the intensity of 100 mW cm(-2). These devices are highly stable under room light in air, even without encapsulation. The present findings offer novel directions for achieving high-efficiency solid-state solar cells by hybridization of inorganic-organic light harvesters and hole transporters.

Evolution of phase and morphology of titanium dioxide induced from peroxo titanate complex aqueous solution.

We demonstrate the growth of anatase TiO2 in nanospheres and rutile TiO2 in nanorods, by the hydrolysis of titanium tetraisopropoxide (TTIP) in the presence of hydrogen peroxide at 100 degrees C using sol-gel method. X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), scanning electron microscopy (SEM), and surface area measurement techniques are used to characterize the phase and shape developments of TiO2 obtained from peroxo titanate complex in an aqueous solution at 100 degrees C. Peroxo titanate complexes were prepared by a reaction of titanium hydroxide, formed by hydrolysis of titanium tetraisopropoxide (TTIP), and different amounts of hydrogen peroxide (H2O2). TEM and XRD investigations reveal that the size of spheres (anatase) and rods (rutile) are about 8 nm (diameter) and about 13 x 29 nm approximately 20 x 75 nm (width x length) respectively. The influence of molar ratio of H2O2/TTIP on the phase and morphology of TiO2 is presented. A mixture of anatase spheres and short rutile rods are formed at low H2O2/TTIP ratio while predominantly rutile a quit long rods are formed at higher H2O2/TTIP ratio.

High-turnover visible-light photoreduction of CO2 by a Re(I) complex stabilized on dye-sensitized TiO2.

Hybrid systems prepared by fixing a Re(i) complex and a dye on three types of TiO2 nanoparticles in two different ways commonly revealed persistent photocatalysis of the CO2 reduction to CO with no levelling-off tendency under visible-light irradiation in DMF, giving a turnover number of ≥435.

Improvement of external quantum efficiency depressed by visible light-absorbing hole transport material in solid-state semiconductor-sensitized heterojunction solar cells.

A mesoporous (mp)-TiO(2)/Sb(2)S(3)/P3HT [poly(3-hexylthiophene)] heterojunction solar cell displays reduced external quantum efficiency (EQE) at a wavelength of approximately 650 nm. This loss in EQE is due to incomplete charge carrier transport because the transportation of charge carriers generated in P3HT by the absorption of light into Sb(2)S(3) was inefficient, and consequently, the carriers recombined. The depression of the EQE was greatly relieved by introducing the porous structure formed by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN) into the P3HT layer.

Multiplexed near-infrared in vivo imaging complementarily using quantum dots and upconverting NaYF4:Yb3+,Tm3+ nanoparticles.

A new multiplexed NIR in vivo imaging is showcased by using quantum dots and NaYF(4):Yb(3+),Tm(3+) nanoparticles. The 'temporal' multiplexing is demonstrated by alternating the excitation wavelengths and unmixing the emissions of different probes. Multiplexed cellular imaging and the cellular trafficking in animal models are shown.

Colloidal TiO2 nanocrystals prepared from peroxotitanium complex solutions: phase evolution from different precursors.

We report the preparation of nanocrystalline anatase and rutile TiO(2) from aqueous peroxotitanium complex (PTC) solutions and their characterization by powder X-ray diffraction (XRD), infrared spectroscopy, and Raman spectroscopy. The phase evolution of TiO(2) prepared using PTC derived from different precursors, i.e., TiCl(4) and titanium tetraisopropoxide (TTIP), is related to the nature of the intermediate steps. Phase-pure nanoanatase was formed in PTC solution derived from TiCl(4), while a mixture of minor anatase and dominant rutile were prepared from PTC when TTIP was used as precursor. On the other hand, in the case of calcining PTC powders in air, a pure anatase phase of TiO(2) was obtained, regardless of the precursor used. Thus, the formation and attachment of hydrated TiO(6) units or TiO(2)·xH(2)O under a different environment, especially pH, plays a critical role in determining the phase during the crystallization of TiO(2).

Organic-inorganic hybrid compounds of Li with bisimidazole derivatives: Li ion binding study and topochemical properties.

The imidazole-based ligands, bis(imidazol-1-yl)methane (Bizm, 1a) and (pyrenyl)bis(imidazol-1-yl) methane (Pbizm,2a) were prepared. With LiClO4, these two compounds formed two novel organic-inorganic hybrid materials: a 3D network polymer Li(Bizm).ClO4 (1b) and a 1D chain polymer Li(Pbizm)2.ClO4 (2b). The intriguing topological and physiochemical characteristics of 1b and 2b are reported on the basis of the X-ray single-crystal structure analysis and Li ion binding studies.