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Multi-stable Operation of a Semiconductor Ring Laser Due to Spatial Hole-Burning
摘要： We have theoretically analyzed multi-stability of a symmetric ring laser operating in one single longitudinal mode in the presence of coherent back scattering and inversion-grating-induced mutual coupling of the clockwise and counter-clockwise modes. Our model takes into account the inversion grating created by the standing-wave pattern of the interfering counter-propagating fields and avoids the frequently used ad-hoc introduction of cross and self-saturation coefficients. Our study confirms that linear coupling due to waveguide irregularities or weak interface reflections leads to an effective pump strength the clock and anti-clock wise modes are below which symmetrically coupled whereas above which the grating-induced coupling leads to multi-stability.
关键词： Coupled oscillator systems,Optical hole burning,Bistable circuits,Semiconductor lasers,Ring lasers
更新于2025-09-11 14:15:04
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Optimizing the Interface between Hole Transporting Material and Nanocomposite for Highly Efficient Perovskite Solar Cells
摘要： The performances of organometallic halide perovskite-based solar cells severely depend on the device architecture and the interface between each layer included in the device stack. In particular, the interface between the charge transporting layer and the perovskite film is crucial, since it represents both the substrate where the perovskite polycrystalline film grows, thus directly influencing the active layer morphology, and an important site for electrical charge extraction and/or recombination. Here, we focus on engineering the interface between a perovskite-polymer nanocomposite, recently developed by our group, and different commonly employed polymeric hole transporters, namely PEDOT: PSS [poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)], PEDOT, PTAA [poly(bis 4-phenyl}{2,4,6-trimethylphenyl}amine)], Poly-TPD [Poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] Poly-TPD, in inverted planar perovskite solar cell architecture. The results show that when Poly-TPD is used as the hole transfer material, perovskite film morphology improved, suggesting an improvement in the interface between Poly-TPD and perovskite active layer. We additionally investigate the effect of the Molecular Weight (MW) of Poly-TPD on the performance of perovskite solar cells. By increasing the MW, the photovoltaic performances of the cells are enhanced, reaching power conversion efficiency as high as 16.3%.
关键词： starch composite,solar cells,organometallic halide perovskite,polymeric hole transporters,interfaces
更新于2025-09-11 14:15:04
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Slow sound laser in lined flow ducts
摘要： This work considers the propagation of sound in a waveguide with an impedance wall. In the low frequency regime, the first effect of the impedance is to decrease the propagation speed of acoustic waves. Therefore, a flow in the duct can exceed the wave propagation speed at low Mach numbers, making it effectively supersonic. This work analyzes a setup where the impedance along the wall varies such that the duct is supersonic then subsonic in a finite region and supersonic again. In this specific configuration, the subsonic region acts as a resonant cavity, and triggers a laser-like instability. This work shows that the instability is highly subwavelength. Besides, if the subsonic region is small enough, the instability is static. This work also analyzes the effect of a shear flow layer near the impedance wall. Although its presence significantly alters the instability, its main properties are maintained. This work points out the analogy between the present instability and a similar one in fluid analogues of black holes known as the black hole laser.
关键词： impedance wall,slow sound,black hole laser,supersonic flow,laser instability,subsonic flow
更新于2025-09-11 14:15:04
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Delamination-free millisecond laser drilling of thermal barrier coated aerospace alloys
摘要： Millisecond (ms) pulsed laser drilling is currently state-of-the-art in producing acute angle film cooling holes over aero-engine and gas-turbine components made from uncoated nickel superalloys. After laser drilling, most of these components are coated with a high-temperature thermal barrier coating (TBC) to maintain the temperature of the component at a level appropriate for its application. It is desirable to produce holes over the TBC coated components; however, the current state-of-the-art ms laser drilling of acute angle holes over TBC coated materials results in a high level of coating delamination and hence is not used in manufacturing industries. The recent introduction of ms quasi-continuous wave (QCW) fiber lasers has had a significant impact on industrial laser drilling. This paper reports the results of a fundamental investigation carried out on ms QCW laser drilling of angular holes over TBC coated superalloys and provides a pragmatic solution to the issue of TBC delamination. In addition to the investigation on traditional percussion and trepanning laser drilling processes, a new method of drilling called 'laser drilling post-laser TBC decoating' is evaluated with the aim of achieving delamination-free laser drilling of TBC coated aerospace alloy.
关键词： millisecond,thermal barrier coating,laser,drilling,angular,fiber,trepanning,TBC,hole,quasi-CW
更新于2025-09-11 14:15:04
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Fluorine Substituted Benzotriazole Core Building Block Based Highly Efficient Hole Transporting Materials for Mesoporous Perovskite Solar Cells
摘要： Two novel donor-accepter-donor (D-A-D) structured hole transporting materials based on fluorine substituted benzotriazole (BTA) core building block (2FBTA-1, 2FBTA-2) are designed and synthesized through the molecular regulation. Applied these materials into perovskite solar cell (PSC), power conversion efficiencies (PCEs) of 7.55 % and 17.94% are obtained for 2FBTA-1 and 2FBTA-2, respectively. The better photovoltaic performance of 2FBTA-2 could be attributed to its more suitable energy level, more planar molecular configurations and higher hole mobility. Moreover, the devices with 2FBTA-2 as HTM show good stability under the air condition. The results qualify the BTA promising building block for future HTM design.
关键词： perovskite solar cell,photovoltaic,benzotriazole,hole transporting material
更新于2025-09-11 14:15:04
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Spectroscopic and Simulation Analysis of Facile PEDOT:PSS Layer Deposition-Silicon for Perovskite Solar Cell
摘要： In this research work, we have characterized and simulated a well-known hole transport material (HTM) for perovskite solar cell (PSC) and conductive polymer poly (3, 4- ethylenedioxy-thiophene) - poly (styrene sulfonate) (PEDOT: PSS). The PEDOT:PSS is a better contender in the field of photovoltaic with its excellent combination of characteristics like high hole conductivity, stability and transparency. The nanocomposite PEDOT:PSS is deposited on the silicon wafer which is N-type doped for the testing the structure characteristic variations. The thin film of PEDOT:PSS over Silicon wafer is prepared with the conventional coating technique and characterized with spectroscopic techniques. The structural behavior has been disclosed under the comprehensive study of Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM), and X-Ray Diffractometer (XRD) mapping. On the other hand, the important optical properties were revealed by detailed analysis by spectroscopy characterization (FTIR, UV-vis, Raman spectra) covering the range of 200–2500 nm. The maximum absorbance range of PEDOT:PSS is 270–320 nm with maximum absorption at 280.5 nm. The photovoltaic cell is simulated by using Spiro-OMeTAD and PEDOT:PSS as Hole Transport Layer (HTL) for a better comparison in terms of power efficiency, quantum efficiency and fill factor. The PSC device shows exemplary power efficiency of 11.89% and 12.13% for PEDOT:PSS & Spiro-OMeTAD as HTL respectively.
关键词： FESEM,Perovskite,Hole transport layer,FTIR,Spectroscopic analysis,Raman spectra,PEDOT:PSS
更新于2025-09-11 14:15:04
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Enhanced photovoltaic performance of solution-processed Sb2Se3 thin film solar cells by optimizing device structure
摘要： Thin-film solar cells have attracted worldwide attention due to their high efficiency and low cost. Antimony selenide (Sb2Se3) is a promising light absorption material candidate for thin-film solar cells due to its suitable band gap, abundance, low toxicity, and high chemical stability. Herein, we fabricate an Sb2Se3 thin film solar cell using a simple hydrazine solution process. By controlling the thickness of the photoactive layer and inserting a poly(3-hexylthiophene) hole-transporting layer, an Sb2Se3 solar cell with a power conversion efficiency of 2.45% was achieved.
关键词： hole-transporting layer,n-i-p structure,solution process,poly(3-hexylthiophene),antimony Selenide,thin film solar cell
更新于2025-09-11 14:15:04
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Mg Doped CuCrO2 as Efficient Hole Transport Layers for Organic and Perovskite Solar Cells
摘要： The electrical and optical properties of the hole transport layer (HTL) are critical for organic and halide perovskite solar cell (OSC and PSC, respectively) performance. In this work, we studied the effect of Mg doping on CuCrO2 (CCO) nanoparticles and their performance as HTLs in OSCs and PSCs. CCO and Mg doped CCO (Mg:CCO) nanoparticles were hydrothermally synthesized. The nanoparticles were characterized by various experimental techniques to study the effect of Mg doping on structural, chemical, morphological, optical, and electronic properties of CCO. We found that Mg doping increases work function and decreases particle size. We demonstrate CCO and Mg:CCO as efficient HTLs in a variety of OSCs, including the first demonstration of a non-fullerene acceptor bulk heterojunction, and CH3NH3PbI3 PSCs. A small improvement of average short-circuit current density with Mg doping was found in all systems.
关键词： Mg doped CuCrO2,perovskite solar cells,hole transport layer,organic solar cells
更新于2025-09-11 14:15:04
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P‐13.8: Influences of Passivation Hole Etching on the ITO and Metal Contact for Bottom Emission AMOLED Display
摘要： A top-gate self-aligned a-IGZO TFT backplate with white OLED and color filter was demonstrated in this paper. Three kind of PV (passivation) hole etching sequences noted as case 1~3, were studied to verify the contact between ITO and Source/Drain electrode. For case 3, PV hole etching process after PLN patterning shows smooth metal surface and excellent panel performance. In contrast, Sourse and Drain metal corrosion occurred due to non-uniform PV film deposition in other two cases , resulting in bad contact between ITO and S/D metal and poor panel performance.
关键词： COA,corrosion,Passivation Hole Etching
更新于2025-09-11 14:15:04
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Fast Electron and Slow Hole Relaxation in InP-Based Colloidal Quantum Dots
摘要： Colloidal InP-based quantum dots are a promising material for light-emitting applications as an environment friendly alternative to their Cd-containing counterparts. Especially for their use in optoelectronic devices, it is essential to understand how charge carriers relax to the emitting state after injection with excess energy and if all of them arrive at this desired state. Herein, we report on time-resolved differential transmission measurements on colloidal InP/ZnS and InP/ZnSe core/shell quantum dots. By optically exciting and probing individual transitions, we are able to distinguish between electron and hole relaxation. This in turn allows us to determine how the initial excess energy of the charge carriers affects the relaxation processes. According to the electronic level scheme, one expects a strong phonon bottleneck for electrons, while holes should relax easier as their energy levels are more closely spaced. On the contrary, we find that electrons relax faster than holes. The fast electron relaxation occurs via an efficient Auger-like electron-hole scattering mechanism. On the other hand, a small wave function overlap between core and shell states slows the hole relaxation down. Additionally, holes can be trapped at the core/shell interface leading to either slow detrapping or nonradiative recombination. Overall, these results demonstrate that it is crucial to construct devices enabling the injection of charge carriers energetically close to their emitting states in order to maximize the radiative efficiency of the system.
关键词： InP,differential transmission spectroscopy,phonon bottleneck,charge carrier relaxation,trap states,electron-hole scattering,colloidal quantum dots
更新于2025-09-11 14:15:04