Lead halide perovskite solar cells have recently emerged as a very promising photovoltaic technology due to their excellent power conversion efficiencies; however, the toxicity of lead and poor stability materials remain two main challenges that need be addressed. Here, for first time, we report lead-free, highly stable C6H4NH2CuBr2I compound. The films exhibit extraordinary hydrophobic behavior with contact angle ∼90°, X-ray diffraction patterns unchanged even after 4 h water immersion....

MAX phase materials, exhibiting excellent antioxidation, corrosion resistance and high electrical optical conductivity, attract much attention. The nonlinear properties of the Ti2AlC was demonstrated by measuring saturable absorption Ti2AlC- polyvinyl (PVA) film. modulation depth Ti2AlC-PVA film is calculated to be 2.21%. Stable Q-switched mode-locked pulses train were achieved in Erbium-doped fiber ring cavity using as a absorber. maximum single pulse energy laser 92.8 nJ, width 680 fs....

Physically unclonable function (PUF) methods have high security, but their wide application is limited by complex encoding, large database, advanced external characterization equipment, and complicated comparative authentication. Therefore, we creatively propose the physically holographic encryption anticounterfeiting based on light propagation of medium fluorescent labels. As far as know, this first method with a fluorescence property. The proposed reduces above requirements traditional PUF...

Bidirectional rotating thrust bearings are critical components for the development of bidirectional equipment. This paper presents design and numerical study an oil-lubricated bearing with novel herringbone grooves, which consists three groups spiral grooves. The lubrication mechanism grooves is revealed. static characteristics numerically investigated by solving Reynolds equation applying finite element method. influences radial width, depth, angle, circumferential width ratio, number...

The Schottky barrier height of Ni on n-GaN has been measured to be 0.56 and 0.66 eV by capacitance–voltage (C–V) current–density–temperature (J–T) methods, respectively. Gallium nickel (Ga4Ni3) is formed as deposited the GaN film, which affects markedly. thermal stability also investigated annealing these specimens at various temperatures. Specimen temperatures above 200 °C leads formation nitrides Ni3N Ni4N interface GaN. These interfacial compounds change 1.0 0.8 C–V J–T Comparisons...

We demonstrate all-optical modulation based on ultrafast saturable absorption in graphene-covered-microfiber. By covering the microfiber surface with polydimethylsiloxane supported graphene film along fiber length, a greatly enhanced interaction between propagating light and can be obtained via strong evanescent field of microfiber. The light–graphene results high-speed, broadband maximum depths 5 dB 13 for single-layer bi-layer graphene, respectively. Such modulator is easy to fabricate,...

We report a passively Q-switched and mode-locked erbium-doped fiber laser (EDFL) based on PtSe2, new two-dimensional material, as saturable absorber (SA). Self-started Q-switching at 1560 nm in the EDFL was achieved threshold pump power of 65 mW, maximum 450 mW, single pulse energy is 143.2 nJ. Due to polarization-dependent characteristics PtSe2-based SA, can be switched from state by adjusting polarization state. A train with repetition rate 23.3 MHz width 1.02 ps generated when increases...

The light scattering effect gradually became stronger with increasing content of nanosheets from substrate to surface in the gradient structure.

We demonstrated saturable absorbers (SAs) based on silver nanoparticles (SNPs) by depositing them the end facet of fiber. The SNPs-based SAs showed large modulation depths and high maximum transmittances. With one SA, we built a passively <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -switched erbium-doped fiber laser (EDFL). Self-started -switching at 1564.5 nm in EDFL...

This letter reports the direct observation of radiative recombination in graded base layer InGaP/GaAs heterojunction bipolar transistors (HBTs). For a 1 μm×16 μm emitter HBT, we demonstrate change spontaneous light emission intensity (ΔIout) as current (Δib) HBT is varied from 0 to 5 mA, i.e., an operating light-emitting transistor. We also output modulation at MHz with modulated normal transistor mode operation HBT.

Results of photoconductivity measurements in undoped n-type and Se-doped GaN epitaxial thin films are presented. Similar to the photoluminescence spectra, also shows a broad yellow band centered around 2.2 eV. It is found that persistent (PPC) does exist all studied films. In addition, PPC effects can be observed for pumping photon energy down band. The results reveal origin effect luminescence may arise from same intrinsic defect. shown most probable candidate defect nitrogen antisite.

Low voltage cathodoluminescent characteristics of ZnGa2O4 phosphor grown by rf magnetron sputtering have been investigated from 300 to 700 nm. The effects substrate heating and annealing treatment on the luminescent are also studied. A blue emission peaked at 470 nm is observed. Better properties achieved films which crystal structure with a standard powder x-ray diffraction pattern ZnGa2O4. effect strength ligand field resultant energy levels for investigated. Low-voltage excellent...

Two different kinds of n-type GaN films were prepared by organometallic vapor phase epitaxy, one using trimethylgallium (TMGa) and another triethylgallium (TEGa) as the alkyl source. Schottky diodes with well-behaved current–voltage capacitance–voltage characteristics fabricated. Deep-level transient spectroscopy studies performed on these samples. Three distinct deep levels, labeled E1, E2, E3, measured in film grown TMGa, an activation energy 0.14, 0.49, 1.63±0.3 eV, respectively. Only...

Photoluminescence, resonant Raman scattering, and photoconductivity measurements have been employed to study the yellow emission in undoped $n$-type a set of Se-doped GaN epitaxial films. It is best described by transition from conduction-band edge deep acceptor. Unlike donors acceptors used most previous studies that substitute Ga sites, Se atoms can replace N sites. With this unique fact, we identify origin involves nitrogen antisite. In addition, it found persistent be observed after band...

Brushless direct current motors with Hall sensors have been widely used in myriad industrial and commercial applications due to their simplicity low cost. Meanwhile, the fault tolerant control (FTC) of sensor drives has attracted renewed research attention. During FTC, motor need diagnose Hall-sensor fault(s) reconstruct faulty signal(s). In this context, we propose an innovative fast diagnosis (FFD) method for analyzing different cases diagnosing signal(s) shortest possible time. Compared...

High-capacity optical data storage and information encryption by using glass substrates are fascinating due to merits of expanding the functionality applicability optoelectronic field. However, development substrate-based multi-dimensional methods has remained a challenge because high hardness, brittleness melting temperature glasses. Herein, inspired unique natural structure plant leaves, multicolor micro-texture-based physical unclonable functions (PUFs) fluorescence labels (MTPLs)...

Abstract Achieving reversible large‐span photoluminescence regulation still faces difficulties due to limitations in the design or preparation conditions of related materials. Herein, a universal strategy that combines voltage‐driven molecular orientation with optical synergy between rare earth (RE) doped materials and polymer dispersed liquid crystals (PDLC) is proposed achieve opto‐electrically synergistic induced multi‐response regulation. The obtained Eu(tta) 3 phen/PDLC composites can...

Ohmic contacts with low resistance are fabricated on n-type GaN films using Ti/Ag bilayer metallization. The grown by pressure metalorganic chemical vapor deposition (LP-MOCVD) Si as the dopant. characteristics studied for carrier concentration range from 1.5×1017 to 1.7×1019 cm−3. lowest value specific contact resistivity of 6.5×10−5 Ω cm2 is obtained without annealing. barrier height Ti calculated be 0.067 eV.

We experimentally demonstrate an operation switchable Erbium-doped fiber laser by employing graphene saturable absorber (GSA) on microfiber. With the introducing of a polydimethylsiloxane layer, can be considered as parallel plate microfiber and induces different propagation losses to TE TM modes. By use such polarization sensitive GSA microfiber, Erbium doped with states continuous wave, stable Q-switching, Q-switched mode-locking, continuous-wave achieved simply tuning in cavity. Our...

The improving intrinsic stability, determining the life span of devices, is a challenging task in industrialization inverted perovskite solar cells. most important prerequisite for boosting stability high-quality films deposition. Here, molecule, N-(2-pyridyl)pivalamide (NPP) utilized, as multifunctional resonance bridge between poly(triarylamine) (PTAA) and film to regulate quality promote hole extraction enhancing device stability. pyridine groups NPP couple with phenyl PTAA through π-π...

Graphene saturable absorbers (GSAs) have been widely applied in ultra-fast mode-locked fiber lasers. Thanks to the broadband advantage of graphene, we theoretically and experimentally demonstrate variation modulation depth GSA by employing effect cross absorption modulation. This method provides an easy efficient way modulate characteristics GSA. By varying power, realize all-fiber fundamental laser a harmonic with tunable output pulse width. Results show that widths two lasers can be tuned...