Explore the vast range of titles available.

The performance improvement of conventional CdTe solar cells is mainly limited by doping concentration and minority carrier life time. Alloying CdTe with an isovalent element changes its properties, for example its band gap and behaviour of dopants, which has a significant impact on its performance as a solar cell absorber. In this work, the structural, optical, and electronic properties of CdTe1-xSex films are examined for different Se concentrations. The band gap of this compound changes with composition with a minimum of 1.40 eV for x = 0.3. We show that with increasing x, the lattice constant of CdTe1-xSex decreases, which can influence the solubility of dopants. We find that alloying CdTe with Se changes the effect of Cu doping on the p-type conductivity in CdTe1-xSex, reducing the achievable charge carrier concentration with increasing x. Using a front surface CdTe1-xSex layer, compositional, structural and electronic grading is introduced to solar cells. The efficiency is increased, mostly due to an increase in the short-circuit current density caused by a combination of lower band gap and a better interface between the absorber and window layer, despite a loss in the open-circuit voltage caused by the lower band gap and reduced charge carrier concentration.

Recent improvements in CdTe thin film solar cells have been achieved by using CdTe1−xSex as a part of the absorber layer. This review summarizes the published literature concerning the material properties of CdTe1−xSex and its application in current thin film CdTe photovoltaics. One of the important properties of CdTe1−xSex is its band gap bowing, which facilitates a lowering of the CdTe band gap towards the optimum band gap for highest theoretical efficiency. In practice, a CdTe1−xSex gradient is introduced to the front of CdTe, which induces a band gap gradient and allows for the fabrication of solar cells with enhanced short-circuit current while maintaining a high open-circuit voltage. In some device structures, the addition of CdTe1−xSex also allows for a reduction in CdS thickness or its complete elimination, reducing parasitic absorption of low wavelength photons.

The performance improvement of conventional CdTe solar cells is mainly limited by doping concentration and minority carrier life time. Alloying CdTe with an isovalent element changes its properties, for example its band gap and behaviour of dopants, which has a significant impact on its performance as a solar cell absorber. In this work, the structural, optical, and electronic properties of CdTe Se films are examined for different Se concentrations. The band gap of this compound changes with composition with a minimum of 1.40 eV for x = 0.3. We show that with increasing x, the lattice constant of CdTe Se decreases, which can influence the solubility of dopants. We find that alloying CdTe with Se changes the effect of Cu doping on the p-type conductivity in CdTe Se , reducing the achievable charge carrier concentration with increasing x. Using a front surface CdTe Se layer, compositional, structural and electronic grading is introduced to solar cells. The efficiency is increased, mostly due to an increase in the short-circuit current density caused by a combination of lower band gap and a better interface between the absorber and window layer, despite a loss in the open-circuit voltage caused by the lower band gap and reduced charge carrier concentration.

Background We examined the impact of muscle relaxation on surgical conditions and patients’ postoperative outcome during elective laparoscopic cholecystectomy under balanced anaesthesia. Methods After approval and consent, 57 anaesthetized patients were randomly assigned to group no neuromuscular blockade (No NMB) and deep neuromuscular blockade (Deep NMB), i.e. no twitch response to train-of-four nerve stimulation. Laparoscopic cholecystectomy was performed using the 4-trocar technique with a CO 2 -pneumoperitoneum. Surgical conditions were assessed using a Visual Analogue Scale. Movement of diaphragm or abdominal muscles, inadequate visibility, or breathing and coughing against the ventilator were documented as events reflecting inadequate muscle relaxation. Independently, surgeons could request 0.3 mg/kg rocuronium to improve surgical conditions. Workflow variables were obtained as a surrogate of surgical conditions. Data are presented as mean (95 % confidence interval). The trial is registered at ClinicalTrials.gov (NCT00895778). Results While in 12 of 25 patients of group “No NMB” one or more adverse events impaired the surgical procedure ( p  < 0.001), only 1 of 25 patients of group “Deep NMB” showed an adverse event. Deep NMB resulted in an absolute risk reduction of 0.44 (0.23–0.65) and a number needed to treat of 2.3 (1.5–4.4), respectively. Surgeons requested 0.3 mg/kg rocuronium in 10 of 25 cases (40 %) of group “No NMB” only. This dose significantly improved surgical conditions by an average 62 of 100 possible points. All further variables did not differ between groups. Conclusions Deep NMB ameliorates surgical conditions for laparoscopic cholecystectomy by improved visibility and reduction of involuntary movements.