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931.
Hole‐extraction layer dependence of defect formation and operation of planar CH3NH3PbI3 perovskite solar cells 下载免费PDF全文
Duc Cuong Nguyen Sung‐yoon Joe Na Young Ha Hui Joon Park Ji‐Yong Park Y. H. Ahn Soonil Lee 《固体物理学:研究快报》2017,11(2)
Three planar CH3NH3PbI3 (MAPbI3) solar cells having the same structure except a hole‐extraction layer (HEL) showed distinctive difference in operation characteristics. Analysis of frequency‐dependent capacitance and dielectric‐loss spectra of the three MAPbI3 devices showed two types of recombination‐loss channels with different time constants that we attributed respectively to interface and bulk defects. Discrepancy in defect formation among the three devices with a HEL of PEDOT:PSS, NiOx, or Cu‐doped NiOx was not surprising because grain‐size distribution and crystalline quality of MAPbI3 can be affected by surface energy and morphology of underlying HELs. We were able to quantify interface and bulk defects in these MAPbI3solar cells based on systematic and simultaneous simulations of capacitance and dielectric‐loss spectra, and current–voltage characteristics by using the device simulator SCAPS.
932.
Cho S Li WS Yoon MC Ahn TK Jiang DL Kim J Aida T Kim D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(29):7576-7584
Multiporphyrin dendrimers are among the most promising architectures to mimic the oxygenic light-harvesting complex because of their structural similarities and synthetic convenience. The overall geometries of dendrimers are determined by the core structure, the type of dendron, and the number of generations of interior repeating units. The rigid core and bulky volume of exterior porphyrin units in multiporphyrin dendrimers give rise to well-ordered three-dimensional structures. As the number of generations of interior repeating units increases, however, the overall structures of dendrimers become disordered and randomized due to the flexibility of the repeating units. To reveal the relationship between molecular structure and processes of excitation-energy migration in multiporphyrin dendrimers, we calculated the molecular structure and measured the time-resolved transient absorption and fluorescence anisotropy decays for various hexaarylbenzene-anchored polyester zinc(II) porphyrin dendrimers along with three types of porphyrin dendrons as references. We found that the congested two-branched type dendrimers exhibit more efficient energy migration processes than one- or three-branched type dendrimers because of multiple energy migration pathways, and the three-dimensional packing efficiency of dendrimers strongly depends on the type of dendrons. 相似文献
933.
Abazov VM Abbott B Abolins M Acharya BS Adams M Adams T Agelou M Agram JL Ahn SH Ahsan M Alexeev GD Alkhazov G Alton A Alverson G Alves GA Anastasoaie M Andeen T Anderson S Andrieu B Arnoud Y Arov M Askew A Asman B Assis Jesus AC Atramentov O Autermann C Avila C Badaud F Baden A Bagby L Baldin B Balm PW Banerjee P Banerjee S Barberis E Bargassa P Baringer P Barnes C Barreto J Bartlett JF Bassler U Bauer D Bean A Beauceron S Begalli M Begel M Bellavance A Beri SB Bernardi G Bernhard R Bertram I 《Physical review letters》2006,96(1):011801
We present a search for the standard model Higgs boson in H --> WW(*) decays with e+e-, e+/-mu-/+, and mu+mu- final states in pp collisions at a center-of-mass energy of square root of s = 1.96 TeV. The data, collected from April 2002 to June 2004 with the D0 detector, correspond to an integrated luminosity of 300-325 pb(-1), depending on the final state. The number of events observed is consistent with the expectation from backgrounds. Limits from the combination of all three channels on the Higgs boson production cross section times branching ratio sigma x BR(H --> WW(*) are presented. 相似文献
934.
Data are presented on a fabrication approach that places an isolated single quantum dot at the center of a semiconductor microcavity. The microcavity is based on an all-epitaxial mesa-confined design that is mechanically robust and provides the thermal dissipation needed for a single photon source device technology. Microphotoluminescence is used to reveal single quantum dot emission with the essential optical properties of single quantum emitters. 相似文献
935.
Abazov VM Abbott B Abolins M Acharya BS Adams M Adams T Agelou M Agram JL Ahn SH Ahsan M Alexeev GD Alkhazov G Alton A Alverson G Alves GA Anastasoaie M Andeen T Anderson S Andrieu B Anzelc MS Arnoud Y Arov M Askew A Asman B Jesus AC Atramentov O Autermann C Avila C Ay C Badaud F Baden A Bagby L Baldin B Bandurin DV Banerjee P Banerjee S Barberis E Bargassa P Baringer P Barnes C Barreto J Bartlett JF Bassler U Bauer D Bean A Begalli M Begel M Belanger-Champagne C Bellantoni L Bellavance A 《Physical review letters》2006,97(16):161803
We report a search for the standard model (SM) Higgs boson based on data collected by the D0 experiment at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 260 pb(-1). We study events with missing transverse energy and two acoplanar b jets, which provide sensitivity to the ZH production cross section in the nunu[over]bb[over] channel, and to WH production when the lepton from the W-->lnu decay is undetected. The data are consistent with the SM background expectation, and we set 95% C.L. upper limits on sigma(pp[over]-->ZH/WH)xB(H-->bb[over]) from 3.4/8.3 to 2.5/6.3 pb, for Higgs-boson masses between 105 and 135 GeV. 相似文献
936.
H.Y. Kwon M.J. Shin Y.J. Choi J.Y. Moon H.S. Ahn S.N. Yi S. Kim D.H. Ha S.H. Park 《Journal of Crystal Growth》2009,311(16):4146-4151
We fabricated one-dimensional GaN nanorods on AlN/Si (1 1 1) substrates at various temperatures, and carrier gas flow amount, using the hydride vapor phase epitaxy (HVPE) method. An AlN buffer layer of 50 nm thickness was deposited by RF sputtering for 25 min. Stalagmite-like GaN nanorods formed at a growth temperature of 650 °C. The diameters and lengths of GaN nanorods increase with growth time, whereas the density of nanorods decreases. And we performed the experiments by changing the carrier gas flow amount at a growth temperature of 650 °C and HCl:NH3 flow ratio of 1:40. GaN nanorods, with an average diameter of 50 nm, were obtained at a carrier gas flow amount of 1340 sccm. The shape, structures, and optical characteristics of the nanorods were investigated by field-emission scanning electron microscopy, X-ray diffraction, and photoluminescence. 相似文献
937.
938.
Devices and architectures for photonic chip-scale integration 总被引:1,自引:0,他引:1
J. Ahn M. Fiorentino R. G. Beausoleil N. Binkert A. Davis D. Fattal N. P. Jouppi M. McLaren C. M. Santori R. S. Schreiber S. M. Spillane D. Vantrease Q. Xu 《Applied Physics A: Materials Science & Processing》2009,95(4):989-997
Silicon nanophotonics holds the promise of dramatically advancing the state of the art in computing by enabling parallel architectures
that combine unprecedented performance and ease of use with affordable power consumption. This paper presents a design study
for a many-core architecture called Corona which utilizes dense wavelength division multiplexing (DWDM) for on- and off-chip
communication together with the devices which will be needed to implement such a communication infrastructure. 相似文献
939.
Hyungju Ahn Sudhakar Naidu Du Yeol Ryu Junhan Cho 《Macromolecular rapid communications》2009,30(6):469-474
The phase behavior of a weakly interacting binary system composed of deuterated polystyrene (dPS) and poly(n‐hexyl methacrylate) (PnHMA) was investigated by the turbidity measurement for the binary blend, and by small angle X‐ray scattering (SAXS) and depolarized light scattering for the block copolymers. For the binary dPS/PnHMA blend, a new phase diagram involving both the upper critical solution transition (UCST) and lower critical solution transition (LCST) was observed by the delicate control of molecular weights between dPS and PnHMA. Whereas for the block copolymers such as dPS‐block‐PnHMA and PS‐block‐PnHMA, an order‐to‐disorder transition (ODT) on heating was observed within the experimental temperature range depending on the molecular weight. This coexistence of both a UCST and LCST in the dPS/PnHMA blend consequently represents the experimental evidence that the corresponding (d)PS‐b‐PnHMAs possess not only ODT, but also lower disorder‐to‐order transition (LDOT) character driven by a compressibility difference, although the latter is hindered by thermal degradation.
940.
Ahn JK Akune Y Baranov V Chen KF Comfort J Doroshenko M Fujioka Y Hsiung YB Inagaki T Ishibashi S Ishihara N Ishii H Iwai E Iwata T Kato I Kobayashi S Komatsubara TK Kurilin AS Kuzmin E Lednev A Lee HS Lee SY Lim GY Ma J Matsumura T Moisseenko A Morii H Morimoto T Nakano T Nanjo H Nix J Nomura T Nomachi M Okuno H Omata K Perdue GN Podolsky S Sakashita K Sasaki T Sasao N Sato H Sato T Sekimoto M Shinkawa T Sugaya Y Sugiyama A Sumida T Suzuki S Tajima Y Takita S Tsamalaidze Z Tsukamoto T Tung YC 《Physical review letters》2008,100(20):201802
We performed a search for the K L0-->pi0nu nu[over] decay at the KEK 12-GeV proton synchrotron. No candidate events were observed. An upper limit on the branching ratio for the decay was set to be 6.7 x 10(-8) at the 90% confidence level. 相似文献