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Quantum dot-sensitized solar cells (QDSSCs) have emerged as a promising solar architecture for next-generation solar cells. The QDSSCs exhibit a remarkably fast electron transfer from the quantum dot (QD) donor to the TiO2 acceptor with size quantization properties of QDs that allows for the modulation of band energies to control photoresponse and photoconversion efficiency of solar cells. To understand the mechanisms that underpin this rapid charge transfer, the electronic properties of CdSe and PbSe QDs with different sizes on the TiO2 substrate are simulated using a rigorous ab initio density functional method. This method capitalizes on localized orbital basis set, which is computationally less intensive. Quite intriguingly, a remarkable set of electron bridging states between QDs and TiO2 occurring via the strong bonding between the conduction bands of QDs and TiO2 is revealed. Such bridging states account for the fast adiabatic charge transfer from the QD donor to the TiO2 acceptor, and may be a general feature for strongly coupled donor/acceptor systems. All the QDs/TiO2 systems exhibit type II band alignments, with conduction band offsets that increase with the decrease in QD size. This facilitates the charge transfer from QDs donors to TiO2 acceptors and explains the dependence of the increased charge transfer rate with the decreased QD size. [ABSTRACT FROM AUTHOR]

Knowledge, regarding sun protection, is essential to change behaviour and to reduce sun exposure of patients at risk for skin cancer. Patient education regarding appropriate or sun protection measures, is a priority to reduce skin cancer incidence. The aim of this study was to evaluate the knowledge about sun protection and the recommendations given in a population of non-dermatologists physicians involved in the care of patients at high risk of skin cancer. This study is a cross-sectional study. Physicians were e-mailed an anonymous questionnaire evaluating the knowledge about risk factors for skin cancer, sun protection and about the role of the physician in providing sun protection recommendations. Of the responders, 71.4% considered that the risk of skin cancer of their patients was increased when compared with the general population. All the responders knew that UV-radiations can contribute to induce skin cancers and 71.4% of them declared having adequate knowledge about sun protection measures. A proportion of 64.2% of them declared that they were able to give sun protection advices: using sunscreens (97.8%), wearing covering clothes (95.5%), performing regular medical skin examination (91.1%), to avoid direct sunlight exposure (77.8%), avoiding outdoor activities in the hottest midday hours (73.3%) and practising progressive exposure (44.4%). Non-dermatologist physicians reported a correct knowledge of UV-induced skin cancer risk factors. The majority of responders displayed adequate knowledge of sun protection measures and declared providing patients with sun protection recommendation on a regular basis. Several errors persisted. [ABSTRACT FROM AUTHOR]

The article offers information on the U.S. Solar Decathlon, an architectural competition that takes place every two years, that will be held at the National Mall in Washington, D.C., from October 12 to 20, 2007. The competition seeks out the newest and best innovations in solar architecture and encourages cutting-edge research into the design of highly efficient and commercially cost-effective solar-powered housing. It offers an overview of the contests included in the competition.