| 1. |
- Ferreira, MA, et al.
(författare)
-
Genome-wide association and transcriptome studies identify target genes and risk loci for breast cancer
- 2019
-
Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 1741-
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified more than 170 breast cancer susceptibility loci. Here we hypothesize that some risk-associated variants might act in non-breast tissues, specifically adipose tissue and immune cells from blood and spleen. Using expression quantitative trait loci (eQTL) reported in these tissues, we identify 26 previously unreported, likely target genes of overall breast cancer risk variants, and 17 for estrogen receptor (ER)-negative breast cancer, several with a known immune function. We determine the directional effect of gene expression on disease risk measured based on single and multiple eQTL. In addition, using a gene-based test of association that considers eQTL from multiple tissues, we identify seven (and four) regions with variants associated with overall (and ER-negative) breast cancer risk, which were not reported in previous GWAS. Further investigation of the function of the implicated genes in breast and immune cells may provide insights into the etiology of breast cancer.
|
|
| 2. |
- Rey, G., et al.
(författare)
-
Absorption Coefficient of a Semiconductor Thin Film from Photoluminescence
- 2018
-
Ingår i: Physical Review Applied. - : AMER PHYSICAL SOC. - 2331-7019. ; 9:6
-
Tidskriftsartikel (refereegranskat)abstract
- The photoluminescence (PL) of semiconductors can be used to determine their absorption coefficient (a) using Planck's generalized law. The standard method, suitable only for self-supported thick samples, like wafers, is extended to multilayer thin films by means of the transfer-matrix method to include the effect of the substrate and optional front layers. a values measured on various thin-film solar-cell absorbers by both PL and photothermal deflection spectroscopy (PDS) show good agreement. PL measurements are extremely sensitive to the semiconductor absorption and allow us to advantageously circumvent parasitic absorption from the substrate; thus, a can be accurately determined down to very low values, allowing us to investigate deep band tails with a higher dynamic range than in any other method, including spectrophotometry and PDS.
|
|
| 3. |
- Grini, Sigbjörn, et al.
(författare)
-
Strong Interplay between Sodium and Oxygen in Kesterite Absorbers : Complex Formation, Incorporation, and Tailoring Depth Distributions
- 2019
-
Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 9:27
-
Tidskriftsartikel (refereegranskat)abstract
- Sodium and oxygen are prevalent impurities in kesterite solar cells. Both elements are known to strongly impact performance of the kesterite devices and can be connected to efficiency improvements seen after heat treatments. The sodium distribution in the kesterite absorber is commonly reported, whereas the oxygen distribution has received less attention. Here, a direct relationship between sodium and oxygen in kesterite absorbers is established using secondary ion mass spectrometry and explained by defect analyses within the density functional theory. The calculations reveal a binding energy of 0.76 eV between the substitutional defects Na-Cu and O-S in the nearest neighbor configuration, indicating an abundance of Na Symbol of the Klingon Empire O complexes in kesterite absorbers at relevant temperatures. Oxygen incorporation is studied by introducing isotopic O-18 at different stages of the Cu2ZnSnS4/Mo/soda-lime glass baseline processing. It is observed that oxygen from the Mo back contact and contaminations during the sulfurization are primary contributors to the oxygen distribution. Indeed, unintentional oxygen incorporation leads to immobilization of sodium. This results in a strong correlation between sodium and oxygen, in excellent agreement with the theoretical calculations. Consequently, oxygen availability should be monitored to optimize postdeposition heat treatments to control impurities in kesterite absorbers and ultimately, the solar cell efficiency.
|
|
| 4. |
- Kon, E., et al.
(författare)
-
A multilayer biomaterial for osteochondral regeneration shows superiority vs microfractures for the treatment of osteochondral lesions in a multicentre randomized trial at 2 years
- 2018
-
Ingår i: Knee Surgery Sports Traumatology Arthroscopy. - : Springer Science and Business Media LLC. - 0942-2056 .- 1433-7347. ; 26:9, s. 2704-2715
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose The increasing awareness on the role of subchondral bone in the etiopathology of articular surface lesions led to the development of osteochondral scaffolds. While safety and promising results have been suggested, there are no trials proving the real potential of the osteochondral regenerative approach. Aim was to assess the benefit provided by a nanostructured collagen-hydroxyapatite (coll-HA) multilayer scaffold for the treatment of chondral and osteochondral knee lesions. Methods In this multicentre randomized controlled clinical trial, 100 patients affected by symptomatic chondral and osteochondral lesions were treated and evaluated for up to 2 years (51 study group and 49 control group). A biomimetic coll-HA scaffold was studied, and bone marrow stimulation (BMS) was used as reference intervention. Primary efficacy measurement was IKDC subjective score at 2 years. Secondary efficacy measurements were: KOOS, IKDC Knee Examination Form, Tegner and VAS Pain scores evaluated at 6, 12 and 24 months. Tissue regeneration was evaluated with MRI MOCART scoring system at 6, 12 and 24 months. An external independent agency was involved to ensure data correctness and objectiveness. Results A statistically significant improvement of all clinical scores was obtained from basal evaluation to 2-year follow-up in both groups, although no overall statistically significant differences were detected between the two treatments. Conversely, the subgroup of patients affected by deep osteochondral lesions (i.e. Outerbridge grade IV and OCD) showed a statistically significant better IKDC subjective outcome (+12.4 points, p = 0.036) in the coll-HA group. Statistically significant better results were also found for another challenging group: sport active patients (+16.0, p = 0.027). Severe adverse events related to treatment were documented only in three patients in the coll-HA group and in one in the BMS group. The MOCART score showed no statistical difference between the two groups. Conclusions This study highlighted the safety and potential of a biomimetic implant. While no statistically significant differences were found compared to BMS for chondral lesions, this procedure can be considered a suitable option for the treatment of osteochondral lesions.
|
|
| 5. |
- Li, Shu-Yi, et al.
(författare)
-
Optical properties of reactively sputtered Cu2ZnSnS4 solar absorbers determined by spectroscopic ellipsometry and spectrophotometry
- 2016
-
Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 149, s. 170-178
-
Tidskriftsartikel (refereegranskat)abstract
- We have determined for the first time the device-relevant optical constants of 500 nm and 800 nm-thick Cu2ZnSnS4 absorbers, grown on bare and Mo-coated soda-lime glass (SLG), using spectroscopic ellipsometry (SE). The composition, structure, phase purity and morphology were characterized by X-ray fluorescence, X-ray photoelectron spectroscopy depth profiling, X-ray diffraction, Raman spectroscopy, scanning-electron microscopy and atomic force microscopy. For the SE analysis, carefully determined sample characteristics were utilized to build a multilayer stack optical model, in order to derive the dielectric functions and refractive indices. The SE-derived absorption coefficients from CZTS/SLG samples were compared with those derived from complementary spectrophotometry measurements and found to be in good agreement. The bandgap determined from Tauc plots was E-g=1.57 +/- 0.02 eV. The absorption coefficients just above the bandgap were found to be a few 10(4) cm(-1) and to exceed 10(5) cm(-1) at energies above similar to 2.5 eV, which is much higher than previously found. The sub-bandgap k-value was found to be k similar to 0.05 or less, suggesting that a moderate band tail is present. Separate device characterization performed on identical samples allowed us to assign device efficiencies of, respectively, 2.8% and 5.3% to the 500 nm and 800 nm-thick samples featured in this study.
|
|
| 6. |
- Ren, Yi, et al.
(författare)
-
Evolution of Cu2ZnSnS4 during Non-Equilibrium Annealing with Quasi-in Situ Monitoring of Sulfur Partial Pressure
- 2017
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 29:8, s. 3713-3722
-
Tidskriftsartikel (refereegranskat)abstract
- Chalcogen-based materials like Cu2ZnSnS4 (CZTS) have attracted extensive attention for applications such as photovoltaics and water splitting. However, an inability to monitor the sulfur partial pressure (PS2) during the non-equilibrium annealing process at high temperatures complicates the synthesis of CZTS with controlled optoelectronic properties. Here we demonstrate that PS2 can be monitored by investigating the Sn–S phase transformation. We showed that PS2 drops considerably over the annealing time, causing gradual alterations in CZTS: (i) a change in defect type and (ii) evolution of ZnS and SnxSy phases. With additional ordering treatment, we observed that the low room-temperature photoluminescence energy usually seen in CZTS can result from insufficient PS2 during annealing. It is proven that remarkable Voc beyond 700 mV for solar cells with nonoptimal CdS buffer can be repeatedly achieved when CZTS is prepared under a sufficiently high PS2. An ordering treatment before CdS deposition can further improve Voc to 783 mV.
|
|
| 7. |
|
|
| 8. |
- Ren, Yi, et al.
(författare)
-
Investigation of the SnS/Cu2ZnSnS4 interfaces in Kesterite Thin-Film Solar Cells
- 2017
-
Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 2:5, s. 976-981
-
Tidskriftsartikel (refereegranskat)abstract
- Kesterite Cu2ZnSnS4 (CZTS), having only earth abundant elements, is a promising solar cell material. Nevertheless, the impact of the SnS secondary phase, which often forms alongside CZTS synthesis at high annealing temperature, on CZTS solar cells is poorly studied. We confirm, by means of X-ray diffraction, Raman scattering, and energy dispersive X-ray spectroscopy mapping, that this phase tends to segregate at both the surface and the back side of annealed CZTS films with Cu-poor and Zn-rich composition. Using electron beam-induced current measurements, it is further demonstrated that the formation of SnS on the CZTS surface is harmful for solar cells, whereas the SnS phase can be beneficial for solar cells when it segregates on the CZTS rear. This positive contribution of SnS could stem from a passivation effect at the CZTS/SnS rear interface. This work opens new possibilities for an alternative interface development for kesterite-based photovoltaic technology.
|
|
| 9. |
- Ross, N., et al.
(författare)
-
Cu2ZnSn(S,Se)4 Solar Cell Absorbers from Diffusion of Selenium into Annealed Cu2ZnSnS4 Absorbers
- 2016
-
Ingår i: 2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC). - New York : IEEE. - 9781509027248 ; , s. 492-497
-
Konferensbidrag (refereegranskat)abstract
- Small grain compound-sputtered Copper Zinc Tin Sulfide (CZTS) precursors and large grain recrystallized CZTS solar cell absorbers are annealed at sub-recrystallization temperatures in selenium atmosphere to promote selenium diffusion into the CZTS films. Grazing incidence x-ray diffraction and Raman spectroscopy show the presence of two distinct sulfide and mixed sulfide/selenide phases, with the selenide-like phase more prominent at the front surface of the absorber. Only a narrow range of sulfur-to-selenium ratios is observed in the sulfide/selenide phase. Secondary ion mass spectrometry profiles show a compositional sulfur-selenium gradient for samples annealed at 450 degrees C. Scanning electron microscopy with energy dispersive X-ray spectroscopy reveals that the compositional gradient is formed by a spatial distribution of sulfide/selenide grains, embedded in the remaining sulfide absorber. Sulfur-selenium gradients within single absorber grains are not observed, indicating that the mixed sulfide/selenide phase nucleates and grows in competition with the existing sulfide phase, rather than forming by replacement of anions within existing crystals. IV and EQE measurements of devices fabricated from the selenized absorbers support this conclusion.
|
|
| 10. |
- Ross, N., et al.
(författare)
-
Mixed sulfur and selenium annealing study of compound-sputtered bilayer Cu2ZnSnS4 / Cu2ZnSnSe4 precursors
- 2017
-
Ingår i: 2017 IEEE 44Th Photovoltaic Specialist Conference (PVSC). - : IEEE. - 9781509056057 ; , s. 3269-3274
-
Konferensbidrag (refereegranskat)abstract
- Copper zinc tin sulfide (CZTS) and copper zinc tin selenide (CZTSe) precursor films are compound co-sputtered from metal sulfide and selenide targets. A bilayer precursor consisting of a CZTS-only underlayer and CZTSe-only overlayer is also sputtered. These precursor films are annealed with varying ratios of elemental sulfur and selenium to promote the formation of recrystallized Cu2ZnSn(S, Se) 4 (CZTSSe) solar cell absorber layers with intermediate sulfur-to-selenium ratios Sr=[S]/([S]+[Se]). The films are characterized by scanning electron microscope (SEM) energy dispersive X-ray spectroscopy (EDX), secondary ion mass spectrometry (SIMS), and grazingincidence X-ray diffraction (GIXRD). Selenium-containing precursors produce absorber layers with rougher surfaces, leading to higher short-circuit currents Jsc for some annealing conditions. The Sr value of the crystallized absorber is independent of the ratio of sulfur to selenium in the precursor unless sulfur is deficient in the anneal. Sulfur-selenium distribution in bilayer precursors after mixed S/Se annealing is found to be uniform: neither a step nor significant sulfur-gradient remains. We relate the chalcogen distribution after annealing to the excess of chalcogen in the anneal, and discuss the consequences for back-grading of the band gap by sulfur-selenium variation. Both the thickness and Sr value of the Mo(S, Se) 2 back contact is found to be dependent on the sulfur-selenium ratio of the precursor, with CZTSe precursors producing thicker and more selenium rich back contact layers.
|
|
