We study the magnitude of metastable light-induced changes in undoped hydrogenated amorphous silicon (the Staebler-Wronski effect) with electron-spin-resonance and photoconductivity measurements. The influence following parameters is investigated a systematic way: sample thickness, impurity content, illumination time, light intensity, photon energy, annealing temperatures. experimental results can be explained quantitatively by model based on nonradiative recombination photoexcited carriers...

The stability of a tin-based perovskite solar cell is major challenge. Here, hybrid cells in new series that incorporate nonpolar organic cation, guanidinium (GA+ ), varied proportions into the formamidinium (FA+ ) tin triiodide (FASnI3 crystal structure presence 1% ethylenediammonium diiodide (EDAI2 as an additive, are reported. device performance optimized at precursor ratio (GAI:FAI) 20:80 to attain power conversion efficiency (PCE) 8.5% when prepared freshly; efficiencies continuously...

Data are presented which show that a major part of the localized electronic state distribution in hydrogenated amorphous silicon is thermal equilibrium at elevated temperatures. Measurements transport reported, with particular emphasis on effects annealing and cooling samples. Two regimes behavior observed. When samples cooled below temperature ${T}_{E}$, atomic structures slowly relax temperature-dependent time constant. In n-type relaxation several weeks room temperature, ${T}_{E}$...

The energy dependence of the average optical matrix element for both hydrogenated amorphous (a-Si:H) and crystalline silicon (c-Si) has been determined experimentally, with use density states imaginary part dielectric function. valence- conduction-band a-Si:H c-Si were measured x-ray photoemission inverse spectroscopy, respectively. Using sub-band-gap by isothermal capacitance transient a nearly complete experimental determined. function was ellipsometry photothermal deflection spectroscopy....

Abstract Hydrogen diffusion in doped and compensated a-Si:H has been measured by secondary-ion mass spectrometry profiling the temperature range 155-300°C. Doping reduces activation energy enhances coefficient up to three orders of magnitude at 200°C, a correlation between dangling-bond density is found. An analysis different models indicates that breaking weak Si – bonds hydrogen may be an important process. The relation results thermal equilibration electronic structure discussed. over...

Changes in the composition and electronic properties of plasma-deposited $a$-Si: H after annealing at temperatures through 600\ifmmode^\circ\else\textdegree\fi{} C are studied by ESR, luminescence, infrared spectroscopy hydrogen evolution. The generation paramagnetic defects on is found to depend only amount evolved. relation peaks hydrogen-evolution rate specific local hydrogen-bonding environments shown be dominated effects diffusion sample microstructure.

By studying the step coverage of plasma-deposited amorphous silicon and germanium on patterned substrates, we find that film formation process under device-quality deposition conditions has a substantial component behaves like surface rate-limited chemical vapor process, while producing defective material are associated with much more physical-vapor-deposition-like process. An explanation involving reactions SiHx radicals is proposed.

We report on a detailed study of structural and electronic properties hydrogenated amorphous silicon-germanium alloys deposited by rf glow discharge from SiH4 GeH4 in diode reactor. The chemical composition the is related to deposition conditions, with special emphasis preferential incorporation Ge into solid phase role inert dilutant gases. Hydrogen bonding investigated nuclear magnetic resonance vibrational (Raman infrared) spectroscopy. optical a-SiGe:H samples under optimal conditions...

We have cocrystallized the drug ethidium bromide with dinucleoside monophosphate 5-iodouridylyl(3'-5')adenosine and solved three-dimensional structure to atomic resolution by x-ray crystallography. This has allowed direct visualization of intercalative binding this a fragment nucleic acid double helix.

Amorphous semiconducting films of the Si-B binary system have been prepared by rf plasma decomposition silane-diborane gas mixtures. The infrared vibrational modes, optical absorption, conductivity, spin resonance, and hydrogen content these studied as a function preparation conditions. These alloy differ substantially from chalcogenide glasses on one hand group-IV amorphous semiconductors other. They contain between 10- 45-at.% ${10}^{18}$ ${10}^{19}$ ${\mathrm{cm}}^{\ensuremath{-}3}$...

Remarkable power conversion efficiencies (PCE) of metal–halide perovskite solar cells (PSCs) are overshadowed by concerns about their ultimate stability, which is arguably the prime obstacle to commercialization this promising technology. Herein, problem addressed introducing ethane‐1,2‐diammonium ( + NH 3 (CH 2 ) , EDA 2+ cations into methyl ammonium MA lead iodide perovskite, enables, inter alia, systematic tuning morphology, electronic structure, light absorption, and photoluminescence...

Abstract We synthesized and characterized methylammonium (MA) mixed tri‐halide tin perovskites (MASnIBr 2− x Cl ) for carbon‐based mesoscopic solar cells free of lead hole‐transporting layers. Varied SnCl 2 /SnBr ratios yielded with three halides (I, Br, Cl) co‐crystallized inside the tin‐perovskite. When proportion was ≥50 % ( ≥1), phase separation occurred to give MASnI 3− y Br MASnCl z in stoichiometric proportions their precursors, confirmed by XRD. A device MASnIBr 1.8 0.2 (SnCl =10 %)...

We report the synthesis and characterization of alloyed Sn–Pb methylammonium mixed-halide perovskites (CH3NH3SnyPb1–yI3–xClx) to extend light harvesting toward near-infrared region for carbon-based mesoscopic solar cells free organic hole-transport layers. The proportions Sn in are well-controlled by mixing tin chloride (SnCl2) lead iodide (PbI2) varied stoichiometric ratios (y = 0–1). SnCl2 plays a key role modifying lattice structure perovskite, showing anomalous optical optoelectronic...

The diffusive transport of hydrogen is used to investigate H trapping in hydrogen-depleted amorphous Si (a-Si) samples and determine a rough H-diffusion density states. diffusion profiles show clear evidence deep traps separated from shallow traps, the results are well explained by simple division states into concentration about (0.8--2)\ifmmode\times\else\texttimes\fi{}${10}^{20}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$, which 30% can be identified with dangling bonds. energy at least...

The hydrogen concentration and density of amorphous semiconducting films prepared by glow-discharge decomposition silane have been measured as a function deposition temperature. An inductively coupled well capacitively plasma-decomposition system was used. For samples the system, content decreased from 26 to 8 at.% increased 1.9 2.27 g/cm3 substrate temperature 25 450 °C.

We have investigated the time and intensity dependence of creation process for light-induced metastable defects (Staebler–Wronski effect) in hydrogenated amorphous silicon (a-Si:H). The observed changes electron spin resonance density (dangling bonds) photoconductivity are consistent with a model which explains Staebler–Wronski effect as self-limiting intrinsic to a-Si:H. A possible microscopic mechanism based on nonradiative recombination band tail carriers is discussed.

The conductance of amorphous Si films produced by glow discharge SiH4 is found to be very sensitive various adsorbates such as water, ammonia, and dimethyl ether. Films exposed air light must first heated 150 °C in vacuum remove adsorbed moisture the reversible photoelectronic effect discovered Staebler Wronski. When adsorbates, undoped (about 0.36 μm thick) decreases several orders magnitude; lightly phosphorus-doped increases rapidly then slowly a saturation value which lies above annealed...

9-Aminoacridine forms a crystalline complex with the dinucleoside monophosphate, 5-iodocytidylyl(3'-5')guanosine. We have solved three-dimensional structure of this by x-ray crystallography and observed two distinct intercalative binding modes drug to miniature Watson-Crick double helical structures. The first these involves pseudosymmetric stacking interaction between 9-aminoacridine molecules guanine-cytosine base-pairs. This configuration may be used when intercalating into DNA. second is...

Fabrication of mesoporous carbon-based perovskite solar cells <italic>via</italic> slow crystallization using NMP solvent attained a great device efficiency 15% with preferred orientation the crystals at (004) facet.

Alcohol-based bifunctional ammonium cations, 2-hydroxyethylammonium (HEA+), HO(CH2)2NH3+, were introduced into formamidinium (FA+) tin-based perovskites (HEAxFA1–xSnI3; x = 0–1) to absorb light in carbon-based mesoscopic solar cells. We found that HEA+ cations play a key role control the crystal structures, lattice structures altered from orthorhombic (x 0) rhombohedral 0.2–0.4) with greater symmetry. When was increased 0.6–1.0, tin and iodide vacancies formed generate 3D-vacant...

We demonstrated that two Lewis bases - urea and thiourea acted as efficient additives for CH3NH3(MA)PbI3-x Cl x MAPbI3 perovskite solar cells (PSCs) observed a significant increase in PCE the devices presence of 1% with remarkable 18.8% using an extremely low annealing temperature (85 °C).

The film thickness, chemical state, and polarization screening for a-SiN1.4 :H films deposited by glow discharge over hydrogenated amorphous silicon (a-Si:H) were determined x-ray photoelectron spectroscopy (XPS) Auger spectroscopy. nitride observed to be single phase the escape depth 1400-eV electrons in was 30 Å. band offsets a-Si:H/a-SiN1.4 interface XPS Bremsstrahlung isochromat (BIS) 1.2 eV valence 2.2 conduction band, while gap found 5.3 accordance with optical gap. By combining...

We report a simple synthetic approach to grow uniform CH3NH3PbI3 perovskite (PSK) layers free of pinholes via varied portions silver iodide (AgI) added the precursor solution. XRD/EDS elemental mapping experiments demonstrated nearly Ag distribution inside film. When 1% AgI-assisted films were fabricated into p-i-n planar device, photovoltaic performance was enhanced by ∼30% (PCE increased from 9.5% 12.0%) relative standard cell without AgI. Measurement electronic properties using hall setup...