Due to low cost and high efficiency, dye-sensitized solar cells (DSSCs) have recently attracted extensive academic and commercial interest for the conversion of sunlight into electricity. 1 Many dyes have been tested as potential sensitizers over the past two decades to improve DSSC performance. The DSSCs can be classified into two types, namely, Type I and Type II, depending on the electroninjection pathway from the dye to the conduction band (CB) of TiO 2 , 2 as shown in Figure 1.First, upon light absorption, the dye molecules are excited from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). After excitations, the dye molecules inject electrons from the excited state into the TiO 2 conduction band. This process is referred to as a "two-step" electron injection type pathway (Fig. 1, Pathway I). The Type-I dyes can be a variety of Ru(II) complexes, 1,3 coumarin derivatives, 4 metal-porphyrin complexes, 5 and others, 6 which usually possess carboxylic acid or phosphonic acid anchoring groups. Another pathway (Fig. 1, Pathway II) is the "one-step" electron injection from the HOMO of the dye to the conduction band of TiO 2 by the photo-induced excitation of the dye-to-TiO 2 charge-transfer (DTCT) complex. The Type-II dyes are rarely reported, compared with Type-I. As a typical example, catechol dyes having enediol units are an example of Type-II dyes that tend to strongly bind TiO 2 through the chelation of surface Ti(IV) ions, giving rise to intense DTCT bands, 2,7,8 which tend to appear at a wavelength longer than 320 nm along with local bands (arising from the dye itself). Several reports have demonstrated that the photoexcitation of DTCT bands indeed gives rise to very fast (< 100 fs) direct electron injection from the dyes to TiO 2 9,10 in compliance with the Mulliken's CT theory. 11 However, the efficiency of the catechol-sensitzed DSSC was generally quite low, 0.5-2.0%. 6,8 The low efficiency arises from the fast back-electron-transfer rates from reduced TiO 2 to the oxidized dye for path II in contrast to path I. In fact, large portions (> 75%) of charge recombination occur within a few picoseconds in pathway B. 8e,10,13 As a result, the external quantum efficiencies arising from pathway II have never exceeded 10% in any wavelength in the absence of externally applied bias potentials.Another compounds which have also been known to form visible CT complexes with surface Ti(IV) ions, are transitionmetal cyanides, 14-17 which hence give rise to strong DTCT bands. In this respect, the nitrile dyes could be classified as Type-II dyes, which adopt the "one-step" electron injection to the CB of TiO 2 (Pathway II) on DSSC. Thus, the development of dye systems for the electron-injection to TiO 2 which occurs via both pathways I and II, 6a,9c,10 is of great interest from academic and practical points of view. Here, we are interested in the study of the sensitizer bearing nitrile units that bind to the surface of TiO 2 through the chelation of surface Ti(IV) ions. 19 Th...

Objectives: Phthalates are used in a large variety of products including as coatings of pharmaceutical tablets, film formers, stabilizers, dispersants, emulsifying agents, and suspending agents. They have been the subject of great public concern in recent years. The extensive uses of this material have attracted attention and issues regarding its safety have been raised. Methods:In this study, three types of phthalate skin permeation were studied using matrixes such as ointments, creams and lotions in vitro. The absorption of phthalate diesters [Dimethyl phthalate (DMP), Din-propyl phthalate (DPP) and Di-n-pentyl phthalate (DNPP)] using film former has been measured in vitro through rat skin. Epidermal membranes were set up in Franz diffusion cells and their permeability to PBS measured in order to establish the integrity of the skin before the phthalates were applied to the epidermal surface.Results: Absorption rates for each phthalate ester were determined and permeability assessment made to quantify any irreversible alterations in barrier function due to contact with the esters. Types of phthalate in vitro experimental results quickly appeared in the following order DMP > DPP ≥ DNPP. Conclusions:In the experimental results, lotion> cream> ointment, and the permeation rate of lotion with a great amount of moisture was the fastest. Skin permeation rate is generally influenced by the chemical characteristics of a given chemical, such as molecular weight and lipophilicity. As the esters became more lipophilic and less hydrophilic, the rate of absorption decreased.