This review describes the main features of dye-sensitized solar cells (DSCs) and highlights recent breakthroughs in this promising thin-film photovoltaic (PV) technology. After a brief presentation of the commercially available technologies, the general operation principles and the most relevant characteristics of DSCs are summarized. Recent major advances in high efficiency sensitizers, nanostructured semiconductors and robust electrolytes offer an opportunity for DSCs integration into the marketplace. With attractive features, like low-cost potential, simple processing, wide range of applicability -from low-power electronics to semi-transparent windowpanes for electricity generation -and good performance under typical operating conditions, these cells are one step from large-scale commercialization. We describe major strategies that are under way to make DSCs a key technology in the future PV paradigm. PV and DSC position in the global energy marketNow, more than ever before, energy is what makes our world continuously work. World energy consumption is ca. 4.7 Â 10 20 J (450 quadrillion Btu) and is expected to grow about 2% each year for the next 25 years.1 Earth's resources upon which the world economy has sustained its grown are finite and governments are increasingly aware of this, particularly now that peak oil is on a near future.2 In order to maintain social and economic development, society is obliged to find a way of making a suitable transition to renewable fuels. This desired change in our energetic paradigm is also being hastened by environmental issues; 3 mankind cannot afford to continue to progress by relying on sources of energy that release greenhouse gases.Nowadays, renewable sources comprise about 13% of all energy production and photovoltaics (PV) account for no more than 0.04% and most probably only in 2030 will that figure reach 1%.4 Solar PV energy costs are not yet competitive and continued PV grow is mainly based on government support, 5 as is easily perceived by analyzing three major consumers: Germany, Japan and the USA (the three combined share about 90% of the world market). 6 Nevertheless, PV solar cells are clearly very elegant and attractive devices for producing energy: cells are free from chemical and noise pollution; their power output is flexible, producing mW as well as MW; production can be done in situ, it is not dependent on the electrical grid, which makes them uniquely portable; they do not rely on reserves located abroad in geopolitically unstable countries and, of course, their source of energythe Sun -is free and inexhaustible for the next few million years. Moreover, the sun's rays reaching the earth are enough to fulfill global energy demand more than 10 thousand times over, i.e. in theory one hour of sunlight is more than enough for a whole year of global consumption. Also, ad extremum, solar energy is the only way of respecting the second law of thermodynamics towards sustainable development, because it benefits from all the massive creation of entropy in the sta...

Understanding the oxidation of the purines adenine and guanine is primary to improving electrochemical methods of DNA detection and analysis. Adenine in the solution phase is reported to undergo a complex electrochemical oxidation mechanism that is overall a -6H + , -6eprocess, involving irreversible chemical steps. The observed voltammetry associated with the oxidation of adenine is strongly dependent upon the electrode used; this is a reflection of both the kinetics of oxidation and strength of bonding to the electrode surface, both of which are surface specific. Two main cases are presented within the article, one in which the adsorption of adenine to the electrode surface is strong, as is the case with gold and one in which the bonding is weaker, as found with graphitic surfaces. In the case of gold, adsorption is strong enough to prevent the adenine oxidation to be observed within the electrochemical window and further to this the formed monolayer prevents oxidation of the gold surface. With graphitic surfaces adsorption is weaker and as such oxidation of adenine is observed, this oxidative signal is demonstrated to be due to the oxidation of both surface bound and solution phase species. A generic method for analyzing the peak currents for reversible electron transfers coupled with an irreversible chemical process is presented. The analysis is dependent upon knowledge of the number of electrons transferred prior to the first chemically irreversible process and the total number of electrons transferred during the redox process. In addition to this, the analysis provides a description for the peak height of voltammetric waves that have contributions from both adsorbed and solution phase species, with these two processes being resolved through their differing dependencies with scan rate. The methodology is then used for the analysis of the oxidation of adenine on an edge-plane pyrolytic graphite electrode, where the influences on peak current from adsorption and diffusion are demonstrated. The diffusion coefficient for adenine is found to be (1.25 ( 0.2) × 10 5 cm s -1 , which is in close agreement to that found by independent measurements reported in the literature. The adsorption of adenine at low concentrations to the electrode surface, is shown to exhibit a linear dependence of coverage with the solution phase concentration, where the surface coverage is given by Γ ) KC* with a measured K value of (1.7 ( 0.1) × 10 -3 cm and C* is the solution phase concentration.

Cardamonin, as shown by the increasing number of publications, has received growing attention from the scientific community due to the expectations toward its benefits to human health. In this study, research on cardamonin is reviewed, including its natural sources, health promoting aspects, and analytical methods for its determination. Therefore, this article hopes to aid current and future researchers on the search for reliable answers concerning cardamonin's value in medicine.