A5018107495- Thin-Film Transistor Technologies
- Silicon and Solar Cell Technologies
- Silicon Nanostructures and Photoluminescence
- Nanowire Synthesis and Applications
- Laser Material Processing Techniques
- Advanced Sensor and Energy Harvesting Materials
- Advanced Thermoelectric Materials and Devices
- Advanced X-ray Imaging Techniques
- Thermal Radiation and Cooling Technologies
- Spectroscopy and Quantum Chemical Studies
- Conducting polymers and applications
- Analytical Chemistry and Sensors
- Advancements in Semiconductor Devices and Circuit Design
- Electrochemical Analysis and Applications
- Plasmonic and Surface Plasmon Research
- Chalcogenide Semiconductor Thin Films
- Semiconductor materials and interfaces
- Optical Coherence Tomography Applications
- Laser-Ablation Synthesis of Nanoparticles
- Photosynthetic Processes and Mechanisms
- Neuroscience and Neural Engineering
- Thermal properties of materials
- Advanced Optical Sensing Technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Fluorescence Microscopy Techniques
Leibniz Institute of Photonic Technology
2016-2025
Albert Einstein College of Medicine
2024
Photonic Science (United Kingdom)
2013
Max Planck Institute of Microstructure Physics
2009
Klinik für Psychosomatik
2005
Silicon nanowire (SiNW)-based solar cells on glass substrates have been fabricated by wet electroless chemical etching (using silver nitrate and hydrofluoric acid) of 2.7 microm multicrystalline p(+)nn(+) doped silicon layers thereby creating the structure. Low reflectance (<10%, at 300-800 nm) a strong broadband optical absorption (>90% 500 measured. The highest open-circuit voltage (V(oc)) short-circuit current density (J(sc)) for AM1.5 illumination were 450 mV 40 mA/cm(2), respectively...
Three-dimensional flexible solar fabrics based on hydrogenated amorphous silicon (a-Si:H) thin film cells were prepared and characterized. A glass fiber fabric with a polytetrafluoroethylene (PTFE) coating proved to be suitable textile substrate. Interwoven metal wires enable an integrated electrical interconnection. An array of consisting a-Si:H layer stack highly p-type/intrinsic/highly n-type doping profile was deposited onto it. Silver used as the back contact indium tin oxide (ITO)...
We present a concept for core-shell silicon nanowire thin-film solar cell showing strong light trapping. Nanowires are wet chemically etched into several micrometer-thick laser-crystallized thin film on glass. The nanowires equipped with an a-Si heteroemitter deposited as shell around the by plasma-enhanced chemical vapor deposition to achieve radial p-n heterojunction. space between is filled ZnO:Al, acting transparent contact. Our cells reached efficiency of 8.8%. main emphasis this study...
We fabricated an efficient hybrid solar cell by spin coating poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS) on planar multicrystalline Si (mc-Si) thin films. The only 5 μm absorber layers were prepared diode laser crystallization of amorphous deposited electron beam evaporation glass. On these layers, we studied the effect SiOx and Al2O3 terminated surfaces. short circuit density power conversion efficiency (PCE) mc-Si/Al2O3/PEDOT:PSS increase from 20.6 to 25.4 mA/cm2...
In order to facilitate the design freedom for implementation of textile-integrated electronics, we seek flexible transparent conductive electrodes (TCEs) that can withstand not only mechanical stresses encountered during use but also thermal post-treatment. The oxides (TCO) typically used this purpose are rigid in comparison fibers or textiles they intended coat. paper, a TCO, specifically aluminum-doped zinc oxide (Al:ZnO), is combined with an underlying layer silver nanowires (Ag-NW). This...
Scientific and technological progress depend substantially on the ability to image nanoscale. In order investigate complex, functional, nanoscopic structures like, e.g., semiconductor devices, multilayer optics, or stacks of 2D materials, imaging techniques not only have provide images but should also quantitative information. We report material-specific characterization buried with extreme ultraviolet coherence tomography. The method is demonstrated at a laser-driven broadband radiation...
Abstract It is demonstrated that spacer fabrics made of polyester can be coated with Al-doped ZnO (AZO) as thermoelectric (TE) material and conductive silver contact to enable smart textiles. An atomic layer deposition process was used for the AZO coating paste manually applied. A TE generator cooling based on Seebeck Peltier effect observed if a temperature difference or direct current applied, respectively. Both effects were proven exist evaluated. The coefficient determined up 50 µ V · K...
The integration of electronic functionalities into textiles for use as wearable sensors, energy harvesters, or coolers has become increasingly important in recent years. A special focus is on efficient thermoelectric materials. Copper iodide a p-type thermoelectrically active, nontoxic material attractive harvesting and generation because its transparency possible high-power factor. deposition CuI polyester spacer fabrics by wet chemical processes represents great potential textile industry...
In this paper, we demonstrate a two-step laser crystallization process for thin film silicon solar cells on glass. first step 5 µm thick amorphous layer is crystallized by diode to get the absorber. The multicrystalline consists of grains with sizes in range 1 mm 10 mm. second epitaxially an excimer form emitter.Epitaxy was investigated fluence 700 1200 mJ/cm2. resulting thickness emitter measured and numerically simulated, both 185 nm 1100 achieve maximum open circuit voltages 548 mV,...
We present an optimized contacting scheme for multicrystalline silicon thin film solar cells on glass based epitaxially crystallized emitters with a Al 2 O 3 layer and silver back reflector. In first step 6.5 µm thick amorphous absorber is by diode laser. second emitter excimer The covered thickness ranging from 1.0 nm to 2.5 nm, which passivates the surface acts as tunnel barrier. On top of 90–100 reflector deposited. was found have optimal 1.5 resulting in that achieve maximum open‐circuit...
During the preparation of silicon thin film solar cells on glass substrates by diode laser induced liquid phase crystallization (LPC), cracking is an issue. This due to thermal stresses caused high temperature gradients within sample. In this paper, relation between stress and distribution sample during LPC discussed. Experiments for two sets irradiation parameters were done leading crack free or cracked film. Additionally, evolution was modeled numerically. Based simulation, introduced...
Abstract Smart textiles that promise to become sensors and actuators for multiple applications are an active area of research. Conductive formed by coating a fabric with conductive film will play key role in such applications. Here we present contactless mapping the terahertz (THz) conductivity thin films deposited on textiles. These maps enable non-destructive assessment layers therefore identification localization non-uniformities local conductivity. The THz measurements quantitatively...
Recently, polycrystalline silicon thin film solar cells on glass are fabricated by a laser induced liquid phase crystallization (LPC) process. This study compares new economic diode laser, emitting line focus at 980 nm, with the 808 nm normally used concerning its absorption during LPC. We measured optical constants of amorphous spectral ellipsometry and UV/VIS spectroscopy. Together literature data for crystalline combined numerical temperature simulations, we calculated LPC overall power...
Simultaneous and locally resolved determination of the mechanical stress variation free hole concentration using Raman spectroscopy is demonstrated in laser crystallized amorphous silicon layers. Such layers are often used for fabrication thin film solar cells, e.g., on borosilicate glass substrates. The combined effects doping signal can be separated based use three wavelengths visible. results show that samples investigated varies between 1×1018 1.3×1019 cm−3. Stress as well vary...
Abstract Silicon nanowire (SiNW) based solar cells are a promising candidate for third generation with high efficiency, which will further reduce the cost of PV modules, making it competitive conventional energy sources. In this paper wet chemical etching process generating silicon nanowires is investigated on different low‐cost substrate materials. These useful radial pn‐junction cell core–shell configuration, allows using absorber materials low‐carrier lifetime. work, applied to...
We report on the fabrication of spherical Au spheres by pulsed laser treatment using a KrF excimer (248 nm, 25 ns) under ambient conditions as fast and high throughput technique. The presented experiments were realized initial layers 100 nm thickness deposited optically transparent low cost Borofloat glass or single-crystalline SrTiO3 substrates, respectively. High (111)-orientation smoothness (RMS ≈ 1 nm) are properties before treatment. After treatment, with size distribution ranging from...
We present a tabletop setup for extreme ultraviolet (EUV) reflection spectroscopy in the spectral range from 40 to 100 eV by using high-harmonic radiation. The simultaneous measurements of reference and sample spectra with high energy resolution provide precise robust absolute reflectivity measurements, even when operating spectrally fluctuating EUV sources. stability sensitivity are crucial factors many applications attosecond science, spectroscopy, nano-scale tomography. show that accuracy...
The effect of roughness and thickness alumina layers, mimicking the passivation layer commonly used in dye-sensitized photoelectrodes, on molecular adsorption P1 dye, 4-(bi(4-(2,2-dicyano-vinyl)-thiophene-2-yl]-phenyl]-aminobenzoic acid) has been studied using surface-sensitive vibrational sum frequency generation(VSFG) spectroscopy. VSFG spectra reveal formation poorly ordered dye layers relatively rough surfaces where XPS measures a higher loading. Furthermore, these molecules are...