다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications as protective coatings in areas, such as magnetic storage disks, optical windows and micro-electromechanical devices (MEMs).

/pdf/diamond-like-amorphous-carbon-3pczopr0z7.pdf

Diamond-like amorphous carbon

The ionic defects at the surfaces and grain boundaries of organic–inorganic halide perovskite films are detrimental to both the efficiency and stability of perovskite solar cells. Here, we show that quaternary ammonium halides can effectively passivate ionic defects in several different types of hybrid perovskite with their negative- and positive-charged components. The efficient defect passivation reduces the charge trap density and elongates the carrier recombination lifetime, which is supported by density-function-theory calculation. The defect passivation reduces the open-circuit-voltage deficit of the p–i–n-structured device to 0.39 V, and boosts the efficiency to a certified value of 20.59 ± 0.45%. Moreover, the defect healing also significantly enhances the stability of films in ambient conditions. Our findings provide an avenue for defect passivation to further improve both the efficiency and stability of solar cells. Losses in solar cells can be caused by material defects in the bulk or at interfaces. Here, Zheng et al. use quaternary ammonium halides to passivate various perovskite absorbers and prepare solar cells with certified efficiency above 20%, suggesting that both anionic and cation defects are affected.

https://par.nsf.gov/servlets/purl/10056130

Defect passivation in hybrid perovskite solar cells using quaternary ammonium halide anions and cations

Organic photovoltaics (OPVs) evolve in an exponential manner in the two key areas of efficiency and stability. The power conversion efficiency (PCE) has in the last decade been increased by almost a factor of ten approaching 10%. A main concern has been the stability that was previously measured in minutes, but can now, in favorable circumstances, exceed many thousands of hours. This astonishing achievement is the subject of this article, which reviews the developments in stability/degradation of OPVs in the last five years. This progress has been gained by several developments, such as inverted device structures of the bulk heterojunction geometry device, which allows for more stable metal electrodes, the choice of more photostable active materials, the introduction of interfacial layers, and roll-to-roll fabrication, which promises fast and cheap production methods while creating its own challenges in terms of stability.

Stability of polymer solar cells.

Evidence of charge storage in a 5 μ m thick p-i-n diode of a-Si:H under pulsed high level double injection conditions was observed in a reverse-recovery experiment. Two requirements, a high injection level and a long injection time, need to be satisfied for the presence of charge storage. Under certain conditions, the recovery charge increases with increasing forward pulse and injection time and it decreases with increasing delay time of the reverse pulse bias. A carrier lifetime of about 2 μ s was observed.

Evidence of charge storage in a-Si:H p-i-n diode and lifetime of carriers

The transport propertics of the electrons in i(a-Si:H)in+ (mc-Si:H) junctions are investigatcd by I–U measuremcnts and sweep-out experiments. It is shown that the tunnel and recombination process of thc electrons in the junction dominates the transport properties of the layer devices. The tunnelling and recombining current is effectively prevented by entering an undoped mc-Si:H or a P-doped a-Si:H buffer layer which not only separates the electrons in n+-mc-Si:H layer and dangling bonds defects in the undoped a-Si:H layer but also decreases the interface states in the junction. A diode with better propertics of i(a-Si:H)/n+ (mc-Si:H) junction is obtained by setting a buffer layer, and the layered sample with structure i1(a-Si:H)/n+ (mc-Si:N)/i2(a-Si:H) is also made for performing the sweep-out experiments to probe the transport of electrons in the high level P-doped mc-Si:H films. The experimental results show that the electron mobility is about 0.2 cm2/Vs and the electron density is in the order of 1020cm−3 for the mc-Si:H at a doping level of PH3/SiH4 = 0.16%.



Die Transporteigcnschaften der Elektronen in i(a-Si: H)/n+ (mc-Si:H)-Ubergangen werden mittels I–U-Messungen und „sweep-out”-Experimenten untersucht. Es wird gezcigt, das die Tunnel- und Rekombinationsprozesse der Elektronen im Ubergang die Transporteigenschaften der Schichtelementc dominieren. Der Tunnel- und Rekombinationsstrom wird effektiv verhindert durch Hinzunahme einer undotierten mc-Si: H- oder P-dotierten aSi: H-Bufferschicht, die nicht nur die Elektronen in der n+-mc-Si:H-Schicht und die Dangling-Bond-Defekte in der undotierten a-Si: H-Schicht trennt, sondern auch die Grenzflachenzustande im Ubergang verringert. Eine Diode mit besseren Eigenschaftcn des i(a-Si:H)/n+ (mc-Si:H)-Ubergangs wird mit einer Bufferschicht erhalten und eine geschichtcte Probe mit i1(a-Si:H)/n+ (mc-Si:H)/i2,(a-Si:H)-Struktur wird fur die Drchfuhrung der „Sweep-out”-Experimente hergestellt, um den Elektronentransport in den hochdotierten P-mc-Si:H-Schichtcn zu untersuchen. Die experimentellen Ergebnisse zeigen. das die Elektronenbeweglichkeit etwa 0,2 cm2/Vs betragt und die Elektronendichte in der Grosenordnung von 1020 cm3 fur mc-Si:H bei einem Dotierungsniveau von PH3/SiH4 = 0,16% ist.

Characteristics of i(a-Si:H)/n+(mc-Si:H) Junctions and Electron Transport in P-doped mc-Si:H Films

We introduced a PC61BM layer between the compact TiO2 layer and the perovskite absorber, which forms a porous precursor film, and thus promotes uniform perovskite films with large grain size and improves the device efficiency.

Novel Insight into the Function of PC61BM in Efficient Planar Perovskite Solar Cells

The creation and annealing kinetics of light-induced defects in a-SiSx:H are studied by ESR and LESR measurements. The dispersion of defect creation after prolonged illumination with white light is greater for a-SiSx:H than that for undoped a-Si:H. In addition, the saturated value of the dark spin density is slightly lower for a-SiSx:H than that for a-Si:H. The annealing behavior can be fitted with a Gaussian distribution of annealing activation energies as is the case for undoped a-Si:H. The incorporation of sulfur decreases the peak energy and increases the width of the distribution of activation energies. Light-soaking does not change the low temperature LESR spectrum and LESR spin density.

Kinetics of Light-Induced Deffect Formation and Annealing in Hydrogenated Amorphous Silicon Alloyed with Sulfur

Junction capacitance measurements were used to characterize the properties of nanocrystalline silicon (nc-Si:H) solar cells. These methods included drive-level capacitance profiling (DLCP) to obtain spatially-resolved defect densities, as well as transient photocapacitance (TPC) and transient photocurrent (TPI) spectra to reveal optically responsive states in the band-gap, and to estimate minority carrier behavior before and after lightsoaking. Crystalline volume fractions were estimated using Raman spectroscopy. Previously we had identified at least two types of distinct behaviors in such nc-Si:H materials that depended on the crystalline volume fraction. Here, in one case, we report results indicating that both types of behavior can occur in a single sample, possibly indicating that the structural properties of that sample have evolved during growth.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1946427400028220

Baojie Yan

Papers

Evidence of charge storage in a-Si:H p-i-n diode and lifetime of carriers

Characteristics of i(a-Si:H)/n+(mc-Si:H) Junctions and Electron Transport in P-doped mc-Si:H Films

Novel Insight into the Function of PC61BM in Efficient Planar Perovskite Solar Cells

Kinetics of Light-Induced Deffect Formation and Annealing in Hydrogenated Amorphous Silicon Alloyed with Sulfur

Electronic Properties Of Nanocrystalline Silicon Deposited With Different Crystallite Fractions And Growth Rates