High-Efficiency Silicon Inverted Pyramid-Based Passivated Emitter and Rear Cells.

Surface texturing is one of the most important techniques for improving the performance of photovoltaic (PV) device. As an appealing front texture, inverted pyramid (IP) has attracted lots of research interests due to its superior antireflection effect and structural characteristics. In this paper, we prepare high-uniform silicon (Si) IPs structures on a commercial monocrystalline silicon wafer with a standard size of 156 × 156 mm2 employing the metal-assisted chemical etching (MACE) and alkali anisotropic etching technique. Combining the front IPs textures with the rear surface passivation of Al2O3/SiNx, we fabricate a novel Si IP-based passivated emitter and rear cell (PERC). Benefiting from the optical superiority of the optimized IPs and the improvement of electrical performance of the device, we achieve a high efficiency of 21.4% of the Si IP-based PERC, which is comparable with the average efficiency of the commercial PERC solar cells. The optimizing morphology of IP textures is the key to the improvement of the short circuit current Isc from 9.51 A to 9.63 A; meanwhile, simultaneous stack SiO2/SiNx passivation for the Si IP-based n+ emitter and stack Al2O3/SiNx passivation for rear surface guarantees a high open-circuit voltage Voc of 0.677 V. The achievement of this high-performance PV device demonstrates a competitive texturing technique and a promising prospect for the mass production of the Si IP-based PERC.

Realization of Quasi-Omnidirectional Solar Cells with Superior Electrical Performance by All-Solution-Processed Si Nanopyramids.

Large-scale (156 mm × 156 mm) quasi-omnidirectional solar cells are successfully realized and featured by keeping high cell performance over broad incident angles (θ), via employing Si nanopyramids (SiNPs) as surface texture. SiNPs are produced by the proposed metal-assisted alkaline etching method, which is an all-solution-processed method and highly simple together with cost-effective. Interestingly, compared to the conventional Si micropyramids (SiMPs)-textured solar cells, the SiNPs-textured solar cells possess lower carrier recombination and thus superior electrical performances, showing notable distinctions from other Si nanostructures-textured solar cells. Furthermore, SiNPs-textured solar cells have very little drop of quantum efficiency with increasing θ, demonstrating the quasi-omnidirectional characteristic. As an overall result, both the SiNPs-textured homojunction and heterojunction solar cells possess higher daily electric energy production with a maximum relative enhancement approaching 2.5%, when compared to their SiMPs-textured counterparts. The quasi-omnidirectional solar cell opens a new opportunity for photovoltaics to produce more electric energy with a low cost.

Dramatic decrease of aortic longitudinal elastic strength in a rat model of aortic dissection.

BACKGROUND: This study aimed to evaluate thoracic aortic longitudinal elastic strength in a rat model of aortic dissection (AD). METHODS: Young Sprague Dawley rats were fed 0.25% ß-aminopropionitrile (BAPN). Biomechanical and biochemistry properties of the aorta were analyzed. Elasticity modulus, maximum stretching length, draw ratio, maximum load, maximum strength, and maximum extensibility were measured. RESULTS: More than one-half of BAPN-treated rats (52.9%) died of aortic rupture secondary to AD during the experiment. The diameter of the aneurysms was 6.33 ± 1.17 mm and the length was 9.33 ± 4.95 mm. The maximum diameter was significantly increased in BAPN-treated rats with AD (group B2) compared with rats without AD (group B1) and control group (group A) (P = 0.001 and P < 0.001, respectively), but was not different between group B1 and group A (P = 0.108). Thickness of media and initial area in aorta of BAPN-treated rats were significantly increased compared with control group (P = 0.001 and P < 0.001, respectively), but no difference in initial area was observed between group B1 and group B2 (P = 0.54). Maximum stretching length, draw ratio, maximum load, maximum strength, maximum extensibility, and elasticity modulus were dramatically decreased in group B2 compared with group B1 and group A (group B2 vs. group B1: P < 0.001; group B1 vs. group A: P < 0.001). CONCLUSIONS: We successfully established a rat model of AD with a high incidence of rupture and mortality. Examinations of strain and stress parameters as well as elasticity modulus of the dissected and the nondissected aorta help understand pathogenesis of AD.