Size-tunable mesoporous spherical TiO 2 (MS TiO 2 ) with a surface area of $110 m 2 g À1 have been prepared through combination of ''dilute mixing''-driven hydrolysis of titanium(iv) tetraethoxide and solvothermal treatment. The hierarchically structured MS TiO 2 are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen sorption analysis. Using three different MS TiO 2 (587, 757, and 1554 nm in diameter) as a scattering overlayer on a transparent nanocrystalline TiO 2 film, bi-layered dye-sensitized solar cells (DSCs) have been fabricated. Since the MS TiO 2 particles are comprised of $10 nm nanocrystallites that cluster together to form large secondary spheres, they can function as light scatterers without sacrificing the surface area for dye-uptake. As a result, the present MS TiO 2 -based cells perform a noticeable improvement in the overall efficiency: maximum 9.37% versus 6.80% for the reference cell made of a TiO 2 nanocrystalline film. This extraordinary result is attributed to the dual effects of enhanced dye loading and light scattering.

Herein, we present a simple strategy for broadband light confinement without sacrificing dye-loading capacity by suitably combining multi-layer architecture with hierarchically structured TiO 2 . For this purpose, three distinct TiO 2 hierarchical nanomaterials were exploited to simultaneously realize high internal surface area and a graded series of optical properties (in terms of reflectance and transmittance). The present hierarchically structured multi-layer showed a remarkable improvement in the overall efficiency for dye-sensitized solar cells (DSCs): a maximum of 11.43% at 1 Sun (12.16% at 1/8 Sun) versus 8.15% at 1 Sun (8.26% at 1/8 Sun) for the reference cell made of a nanocrystalline TiO 2 single-layer. This notable result is attributed to the synergetic effects of the enhanced broadband light confinement, dye-loading, and charge-collection efficiency.

Dye‐sensitized solar cells (DSCs) are considered to be a promising alternative to Si‐based photovoltaic cells. The electrolyte of the DSC primarily uses triiodide/iodide (I3−/I−) as a redox couple. Therefore, it is essential to understand the regeneration and recombination kinetics of the I3−/I− redox couples in the device. In this context, controlling the total and local concentrations of the I3−/I− redox couples is an important parameter that can influence the DSC performance. Here, we propose that the introduction of a sodium bis (2‐ethylhexyl) sulfosuccinate (AOT)/water system to the I3−/I− electrolyte enables the control of the concentration of the redox couples, which consequently achieves a high power conversion efficiency of ∼11% for ∼1000 h (under 1 sun illumination) owing to the enhanced dye‐regeneration efficiency and the reduced recombination rate. This novel concept assists in the comprehension of the regeneration and recombination kinetics and develops highly efficient DSCs.

The sea urchin TiO(2) (SU TiO(2)) particles composed of radially aligned rutile TiO(2) nanowires are successfully synthesized through the simple solvothermal process. SU TiO(2) was incorporated into the TiO(2) nanoparticle (NP) network to construct the SU-NP composite film, and applied to the CdS/CdSe/ZnS quantum-dot-sensitized solar cells (QDSSCs). A conversion efficiency of 4.2% was achieved with a short-circuit photocurrent density of 18.2 mA cm(-2) and an open-circuit voltage of 531 mV, which corresponds to ∼20% improvement as compared with the values obtained from the reference cell made of the NP film. We attribute this extraordinary result to the light scattering effect and efficient charge collection.

No abstract

No abstract

No abstract

A novel way to tune the bandgap in an Ag 2 S quantum dot (QD) system is developed by inducing a lattice-distorted region of ≈1-nm scale in a QD with rapid quenching. Accordingly, the bandgap can be controlled simply by tailoring the degree of the lattice-distortion in a QD (2.51 to 1.64 eV). As reported by H. M. Jang and co-workers on page 1300, this conceptual method can pave a new way to realize quantum effects in future QD-based applications.