Differential Reflectivity Research Articles

Hybrid sonoprecipitation fabrication of magnetic ZnO-GO-Fe3O4 nanophotocatalyst for solar-light-driven degradation of dyes in water

ZnO-GO-Fe3O4 as an effective magnetic nanocomposite in photodegradation of water pollutants is prepared via two step procedure and its photocatalytic activity for organic dyes degradation is investigated. The first step is sonoprecipitation synthesis of ZnO over graphene oxide nanosheet and the second step is addition of Fe3O4 nanoparticles by two methods: precipitation synthesis and solvothermal addition. X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Analysis (EDX), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) Surface Area Analysis and Barrett-Joyner-Halenda (BJH) Pore Size and Volume Analysis, Differential reflectance spectroscopy (DRS), Fourier Transform Infrared spectroscopy (FTIR) and Vibrating-Sample Magnetometer (VSM) techniques are employed to examine the characterization of the nanocomposites. The results display high surface area with mesoporous structure and low energy band gap is obtained for ZnO-GO-Fe3O4 synthesized via solvothermal method. Also, ultrasound irradiation increases the available surface area for photoreaction. The degradation percent of eosin yellow and methylene blue are about 60 and 97%, respectively. The effect of initial pH of solution, the amount of loaded photocatalyst and initial dye concentration are investigated in this research.

Dual-Polarization Radar Observations of the Evolution of a Supercell Tornado and Analysis of the Echo Mechanisms

To gain a deeper understanding of the structural and evolutionary characteristics of supercell tornadoes that occurred in eastern China on 14 May 2021, observations from the S-band dual-polarization radars, soundings and other instruments are used to investigate the evolutionary process of the tornado formation by the mergering and strengthening of supercell storms. The results are described as follows. The updraft by upper divergence and vertical thermal instability induced by the cold source at the tropopause provided the environmental conditions suitable for tornado formation. The tornado event involved three storm merger processes, each of which was associated with an increase in the echo intensity, vertical rising speed, and vertical vorticity of the supercell. Furthermore, during the last merger, the merging of the two vortices resulted in the reduction of the rotation radius of the new vortex, which also provided a favorable condition for tornadogenesis. A schematic was proposed to describe storm mergers. The characteristics of the velocity spectrum width were indicative of the occurrence and evolution of the tornado in this case. During the tornado stage, distinct polarimetric variable signatures (e.g., a tornado debris signature and a differential reflectivity arc) and radial velocity signatures (i.e., a tornadic vortex signature) were observed.

Analysis of Two Convective Storms Using Polarimetric X-Band Radar and Satellite Data

We analyzed two convective storms that passed over or near the Milešovka meteorological observatory. The observatory is located at the top of a hill and has been recently equipped with a Doppler polarimetric X-band radar FURUNO WR2120 for cloud investigations. Our analysis was based mainly on Doppler polarimetric radar data measured in vertical cross-sections (RHI-Range-Height Indicator). Radar data was also used for classifying hydrometeors by a newly developed XCLASS (X-band radar CLASSification) algorithm. We also used rapid scan data measured by the geostationary satellite Meteosat Second Generation to validate radar measurements at the upper parts of storms. Although an attenuation correction was applied to the reflectivity and differential reflectivity measurements, the attenuation typical of X-band radars was noticeable. It was mainly manifested in the differential reflectivity, co-polar correlation coefficient and specific differential phase. Nevertheless, radar measurements can be used to analyze the internal cloud structure of severe convective storms. The XCLASS classification was developed by major innovation of a previously published algorithm. The XCLASS algorithm identifies seven types of hydrometeors: light rain, rain, wet snow, dry snow, ice, graupel, and hail. It uses measured horizontal and vertical radar reflectivity, specific differential phase, co-polar correlation coefficient, and temperature, and applies fuzzy logic to determine the type of hydrometeor. The new algorithm practically eliminates unrealistic results around and below the melting layer provided by the original algorithm. It identifies wet snow in more cases, and areas with individual hydrometeors have more realistic shapes compared to the original algorithm. The XCLASS algorithm shows reasonable results for the classification of hydrometeors and can be used to study the structure of convective storms.

Ag/Co/B tri-doped TiO2/SiO2 film for enhancing photocatalytic degradation

Ag/Co/B tri-doped TiO2/SiO2 film was prepared by the sol–gel method, and the structure and properties of this film were characterized by the X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) test method, field emission scanning electron microscopy (FE-SEM), differential thermal analysis-thermogravimetry (DTA-TG), photoluminescence (PL), and UV-visible diffuse reflectance spectrum (UV-vis DRS). XRD results indicated that the film structure of this film conforms to the anatase single crystal form. The presence of SiO2 can inhibit the formation of brookite and prevent the conversion of anatase into rutile. BET and FE-SEM results revealed that the film had a higher specific surface area and smaller grain size compared with pure TiO2 film. DTA-TG results exposed that the film had excellent thermal stability at 450[Formula: see text]C. Due to the spectacular adsorption capacity of SiO2 and the Schottky barrier formed between Ag and TiO2, this film improved the h[Formula: see text]/e[Formula: see text] separation efficiency and optical absorption performance showed by PL results. UV-vis DRS results displayed that the band gap energy (2.47 eV) of the film was clearly lower than that of pure TiO2 film, due to the intermediate energy levels generated by Co and B ions doping. The photocatalytic activity of the film was verified by ultraviolet and visible light degradation experiments of two different organic pollutants. The experimental results exhibited that the film had excellent photocatalytic degradation ability and stability. Ultimately, a possible synergistic mechanism of photocatalysis was proposed in this paper.

Fast Exciton Diffusion in Monolayer PtSe2

AbstractRecently, 2D noble metal dichalcogenides have drawn considerable attention due to their thickness‐tunable electronic and optical properties. However, the dynamical properties of photocarriers in these materials are less studied. Here, photocarrier dynamics in monolayer and bilayer PtSe samples prepared by chemical vapor deposition are studied by transient absorption microscopy. Spatially and temporally resolved differential reflectance measurements yield room‐temperature exciton lifetimes of 25 and 50 ps for monolayer and bilayer samples, respectively. The exciton diffusion coefficient in monolayer PtSe is found to be as large as 48 cm s. This value is higher than exciton diffusion coefficients of most known monolayer semiconductors. The deduced exciton mobility is close to the theoretical limit of charge carrier mobility of monolayer PtSe. The superior exciton transport property is unique to monolayers, as the exciton diffusion coefficient drops to 6.7 cm s in bilayers PtSe. The novel exciton transport properties, along with its high air stability, make monolayer PtSe an attractive material for ultrathin excitonic devices. These results provide insights on the exciton dynamic properties of 2D PtSe and help develop fundamental understanding on the performance of various optoelectronic devices based on 2D PtSe.

A Polarimetric Radar Operator and Application for Convective Storm Simulation

In this study, a polarimetric radar forward model operator was developed for the Weather Research and Forecasting (WRF) model that was based on a scattering algorithm using the T-matrix methodology. Three microphysics schemes—Thompson, Morrison 2-moment, and Milbrandt-Yau 2-moment—were supported in the operator. This radar forward operator used the microphysics, thermodynamic, and wind fields from WRF model forecasts to compute horizontal reflectivity, radial velocity, and polarimetric variables including differential reflectivity (ZDR) and specific differential phase (KDP) for S-band radar. A case study with severe convective storms was used to examine the accuracy of the radar operator. Output from the radar operator was compared to real radar observations from the Weather Surveillance Radar–1988 Doppler (WSR-88D) radar. The results showed that the radar forward operator generated realistic polarimetric signatures. The distribution of polarimetric variables agreed well with the hydrometer properties produced by different microphysics schemes. Similar to the observed polarimetric signatures, radar operator output showed ZDR and KDP columns from low-to-mid troposphere, reflecting the large amount of rain within strong updrafts. The Thompson scheme produced a better simulation for the hail storm with a ZDR hole to indicate the existence of graupel in the low troposphere.

Carbon quantum dots decorated Ag/CuFe2O4 for persulfate-assisted visible light photocatalytic degradation of tetracycline: A comparative study

Tetracycline is a broad-spectrum antibiotic largely found in the environment with many adverse effects on environmental and human health. Recently, the coupling of different advanced oxidation processes has been promised as the effective approach for the degradation of refractory pollutants. In this work, the magnetically separable Ag/CuFe2O4/CQDs photocatalyst was successfully synthesized and characterized by X-ray powder diffraction, Differential reflectance spectroscopy, Transmission Electron Microscopy, Field emission scanning electron microscopy, and Energy-dispersive X-ray spectroscopy analysis. The potential of different systems namely photocatalyst/light, photocatalyst/persulfate and photocatalyst/persulfate/light as well as operation parameters, reusability and involved radicals were evaluated for tetracycline degradation. The highest removal efficiency for the different systems was obtained as photocatalyst/persulfate/light (100%, 30 min) > photocatalyst/persulfate (100%, 55 min) > photocatalyst/light (100%, 75 min). The 47% total organic carbon removal was obtained in optimum condition and intermediate products were proposed based on results of liquid chromatography-mass spectrometry. The results indicated that reaction rate constant (Kobs) decreased from 0.1319 to 0.0270 min−1, 0.0332 min−1 and 0.0174 min−1 with increasing pH, initial tetracycline concentration and humic acid (HA), respectively. The inhibitory effect of inorganic ions was obtained as Cl− < NO3− < HCO3−. The nanocomposite showed high reusability after 5 consecutive cycles (91.5%). The results of the scavenger analysis suggest the superoxide and positive hole are the main species involved in tetracycline degradation.

Terrain Effects on the 13 April 2018 Mountainburg, Arkansas EF2 Tornado

Storm-scale interactions with rough terrain are complex. Terrain has been theorized to impact the strength of low-level mesocyclones. Surface roughness and modifications of the surrounding environment also may impact tornadogenesis or tornado intensity. The Mountainburg, Arkansas EF2 tornado on 13 April 2018 traveled along a path with minor variations in intensity and elevation throughout most of the nearly 19-km (11.8 mi) damage path as the storm moved along a river valley. A detailed damage survey showed that the tornado then made an abrupt ascent of more than 200 m (656 ft) in the last 2 km (1.2 mi) before dissipating. By examining model soundings and conducting a detailed terrain analysis, this study examines what role terrain may have had in channeling the momentum surge and enhancing the low-level vorticity to influence tornadogenesis. Other storm-scale factors are investigated to determine their potential impact on the demise of the tornado. The differential reflectivity column is studied to determine if the updraft was weakening. The relative position of the tornado and mesocyclone also are examined as the tornado ascended the terrain and dissipated to determine whether the change in elevation impacted the overall strength of the storm and to evaluate whether the storm was undergoing a traditional occlusion cycle. Finally, a large-eddy simulation model is used to explore physical changes in a tornado encountering terrain similar to the Mountainburg, Arkansas, tornado near its demise.

Extracting quantitative dielectric properties from pump-probe spectroscopy

Optical pump-probe spectroscopy is a powerful tool for the study of non-equilibrium electronic dynamics and finds wide applications across a range of fields, from physics and chemistry to material science and biology. However, a shortcoming of conventional pump-probe spectroscopy is that photoinduced changes in transmission, reflection and scattering can simultaneously contribute to the measured differential spectra, leading to ambiguities in assigning the origin of spectral signatures and ruling out quantitative interpretation of the spectra. Ideally, these methods would measure the underlying dielectric function (or the complex refractive index) which would then directly provide quantitative information on the transient excited state dynamics free of these ambiguities. Here we present and test a model independent route to transform differential transmission or reflection spectra, measured via conventional optical pump-probe spectroscopy, to changes in the quantitative transient dielectric function. We benchmark this method against changes in the real refractive index measured using time-resolved Frequency Domain Interferometry in prototypical inorganic and organic semiconductor films. Our methodology can be applied to existing and future pump-probe data sets, allowing for an unambiguous and quantitative characterisation of the transient photoexcited spectra of materials. This in turn will accelerate the adoption of pump-probe spectroscopy as a facile and robust materials characterisation and screening tool.

Analytic characterization of random errors in spectral dual-polarized cloud radar observations

Abstract. This study presents the first-ever complete characterization of random errors in dual-polarimetric spectral observations of meteorological targets by cloud radars. The characterization is given by means of mathematical equations for joint probability density functions (PDFs) and error covariance matrices. The derived equations are checked for consistency using real radar measurements. One of the main conclusions of the study is that the convenient representation of spectral polarimetric measurements including differential reflectivity ZDR, correlation coefficient ρHV, and differential phase ΦDP is not suited for the proper characterization of the error covariance matrix. This is because the aforementioned quantities are complex, non-linear functions of the radar raw data, and thus their error covariance matrix is commonly derived using simplified linear relations and by neglecting the correlation of errors. This study formulates the spectral polarimetric measurements in terms of a different set of quantities that allows for a proper analytic treatment of their error covariance matrix. The results given in this study allow for utilization of spectral polarimetric measurements for advanced meteorological applications, among which are variational retrieval techniques, data assimilation, and sensitivity analysis.

Synthesis and analysis of low field high magnetostrictive Ni-Co ferrite for magneto-electric energy harvesting applications

Low field high magnetostrictive cobalt substituted nickel ferrites with composition Ni1-xCoxFe2O4 (x = 0, 0.25, 0.5, 0.75 and 1) were synthesized by sol gel technique. The formation of cubic spinel structure of samples was confirmed by X-ray diffraction. Surface morphology and optical properties were studied by using scanning electron microscopy and Differential Reflectance spectroscopy. The systematic change in the Metal-Oxygen (M−O) bands with Co substitution in nickel ferrite samples was observed in Fourier Transform Infrared spectra. With Co substitution remanance and coercivity values were increased and Curie temperature values were decreased systematically. The magnetostriction was found to increase with the substitution of Co from 10 ppm to a maximum value of about 200 ppm. Ni0.5Co0.5Fe2O4 showed magnetostriction of ∼−63 ppm at 1500 Oe and ∼−85 ppm at 2000 Oe and strain sensitivity value 1.74x10-9A-1m at 1500 Oe.

Inspection of Line Defects in Transition Metal Dichalcogenides Using a Microscopic Hyperspectral Imaging Technique

The line defects of two-dimensional (2D) transition metal dichalcogenides (TMDs) play a vital role in determining their device performance. In this work, a microscopic hyperspectral imaging technique based on differential reflectance was introduced for the online inspection of line defects in TMDs. Upon comparison of the measurement results of imaging and spectra, the relationship between optical contrast and differential reflectance spectra was established. A light selection method was proposed to optimize the optical contrast of line defects. Via application of an image processing algorithm, an automatic detection of the line defects with a classification accuracy of 95% was achieved for WS2, MoS2, and MoSe2. This work not only provides a microscopic hyperspectral imaging technique for detecting 2D material defects but also introduces a versatile design strategy for developing an advanced machine vision spectroscopic system.

Climatology of the Vertical Profiles of Polarimetric Radar Variables and Retrieved Microphysical Parameters in Continental/Tropical MCSs and Landfalling Hurricanes

AbstractMost existing cloud models tend to overestimate the size of cloud ice particles and underestimate their concentration. This emphasizes the need to provide a reliable observational reference to optimize cloud model performance, particularly in areas of high concentration of ice at high altitudes. The dual‐polarization radars give the community a unique opportunity to quantify cloud ice with a good accuracy using polarimetric radar retrievals. In this study, we utilize the network of operational WSR‐88D radars to build a climatology of the vertical profiles of radar variables, such as radar reflectivity Z, differential reflectivity ZDR, and specific differential phase KDP as well as the radar‐retrieved vertical profiles of ice water content (IWC) above the melting layer and liquid water content below it, mean volume diameter Dm, and total number concentration Nt of ice and liquid particles. Such climatology was created for continental/marine mesoscale convective systems (MCSs) and tropical cyclones including hurricanes. The dataset includes 13 continental MCSs, 10 marine MCSs, and 11 tropical cyclones. Separate statistics of the “background” vertical profiles and the ones associated with high IWC aloft have been obtained in the course of this study. It is shown that continental MCSs exhibit larger size of ice in lower concentration aloft compared to the marine MCSs and especially tropical cyclones/hurricanes. A combination of high KDP and low Z aloft signifies lower Dm, higher Nt, and often substantial IWC.

Biaxial versus uniaxial strain tuning of single-layer MoS2

Strain engineering has arisen as a powerful technique to tune the electronic and optical properties of two-dimensional semiconductors like molybdenum disulfide (MoS2). Although several theoretical works predicted that biaxial strain would be more effective than uniaxial strain to tune the band structure of MoS2, a direct experimental verification is still missing in the literature. Here we implemented a simple experimental setup that allows to apply biaxial strain through the bending of a cruciform polymer substrate. We used the setup to study the effect of biaxial strain on the differential reflectance spectra of 12 single-layer MoS2 flakes finding a redshift of the excitonic features at a rate between -40 meV/% and -110 meV/% of biaxial tension. We also directly compare the effect of biaxial and uniaxial strain on the same single-layer MoS2 finding that the biaxial strain gauge factor is 2.3 times larger than the uniaxial strain one.

A practical and effective method for reducing differential reflectance spectroscopy noise

Differential reflectance spectroscopy (DRS) is a powerful tool to study processes during thin-film growth, especially that of transition metal dichalcogenides and organic thin films. To satisfy the requirements for in situ and real-time monitoring of film growth, including spectral resolution and sensitivity at the level of monolayers and even sub-monolayers, the most challenging technical task in DRS is to reduce noise to an extremely low level so that the best possible signal-to-noise ratio can be achieved. In this paper, we present a simplified and cost-effective DRS apparatus, with which we show that the measurement noise is mainly composed of thermal drift noise and explore the temperature-dependence of the DRS signal. Based on the results obtained, we propose an easily realized and effective scheme aiming to reduce the noise. Experimental results demonstrate that this scheme is effective in stabilizing reliable signals for a long period of several hours. Significant noise reduction is achieved, with the typical average noise of the DRS system being decreased to 0.05% over several hours. The improved DRS system is applied to study the growth of an organic semiconductor layer for an organic field-effect transistor device. The results indicate that the apparatus proposed in this paper has potential applications in fabrication of devices on the nanoscale and even the sub-nanoscale.

The surface modification of spherical ZnO with Ag nanoparticles: A novel agent, biogenic synthesis, catalytic and antibacterial activities

Nowadays, the industrial wastewater pollutants including toxic dyes and pathogenic microbes have caused serious environmental contaminations and human health problems. In the present study, eco-friendly and facile green synthesis of Ag modified ZnO nanoparticles (ZnO-Ag NPs) using Crataegus monogyna ( C. monogyna ) extract (ZnO-Ag@CME NPs) is reported. The morphology and structure of the as-biosynthesized product were characterized by field emission scanning electron microscopy (FESEM), X-Ray diffraction (XRD), differential reflectance spectroscopy (DRS), dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy (EDS) techniques. TEM and FESEM images confirmed the oval and spherical-like structure of the products with a size of 55–70 nm. The EDS analysis confirmed the presence of Zn, Ag, and O elements in the biosynthesized product. The photocatalytic results showed ZnO-Ag@CME NPs were degraded (89.8% and 75.3%) and (94.2% and 84.7%) of methyl orange (MO) and basic violet 10 (BV10), under UV and sunlight irradiations, respectively. The Ag modified ZnO nanoparticles exhibited enhanced catalytic activity towards organic pollutants, and showed better performance than the pure ZnO nanoparticles under UV and sunlight irradiations. This performance was probably due to the presence of silver nanoparticles as a plasmonic material. Antibacterial activity was performed against different bacteria. ZnO-Ag@CME NPs showed high antibacterial activity against K. pneumoniae, S. typhimurium, P. vulgaris, S. mitis, and S. faecalis with MIC values of 50, 12.5, 12.5, 12.5, and 12.45 µg/mL, respectively. All in all, the present investigation suggests a promising method to achieve high-efficiency antibacterial and catalytic performance.

Observational Characteristics of Dual-Polarization Radar for Heavy Rainfall Events in Capital Area

In this study, the observational characteristics of dual-polarization radar for studying the heavy rainfall in the capital area were evaluated. To this end, three rainfall events that had caused significant flood damage due to the heavy rainfall from June to August 2020 were selected. The application of dual-polarization radar data revealed a significant change in precipitation during the analysis of observation characteristics of the affected capital area’s heavy rainfall. Moreover, the physical characteristics of reflectivity, differential reflectivity, specific differential phase, and copolar-correlation coefficient and their temporal dynamics in radar rainfall were compared to rain gauge rainfall. The radar reflectivity has been identified at the frequency of ≥ 40 dBZ due to the effects of heavy rainfall in the capital area, while the differential reflectivity has confirmed that the particle size was larger. The specific differential phase seemingly exhibited the most similar distribution to rain gauge rainfall, while exhibiting local characteristics of heavy rainfall in the capital area, according to the differential reflectivity result. The copolar-correlation coefficient confirmed the consistent observational performance of the dual-polarization radar for evaluation of heavy rainfall. Overall, the radar rainfall demonstrated good performance in simulating the peak time, and CSU-HIDRO estimated the rainfall with up to 32.4% more accuracy than JPOLE.

Calibration of radar differential reflectivity using quasi-vertical profiles

Abstract. Accurate precipitation estimation with weather radars is essential for hydrological and meteorological applications. The differential reflectivity (ZDR) is a crucial weather radar measurement that helps to improve quantitative precipitation estimates using polarimetric weather radars. However, a system bias between the horizontal and vertical channels generated by the radar produces an offset in ZDR. Existing methods to calibrate ZDR measurements rely on the intrinsic values of the ZDR of natural targets (e.g. drizzle or dry snow) collected at high elevation angles (e.g. higher than 40∘ or even at 90∘), in which ZDR values close to 0 dB are expected. However, not all weather radar systems can scan at such high elevation angles or point the antenna vertically to collect precipitation measurements passing overhead. Therefore, there is a need to develop new methods to calibrate ZDR measurements using lower-elevation scans. In this work, we present and analyse a novel method for correcting and monitoring the ZDR offset using quasi-vertical profiles computed from scans collected at 9∘ elevations. The method is applied to radar data collected through 1 year of precipitation events by two operational C-band polarimetric weather radars in the UK. The proposed method shows a relative error of 0.1 dB when evaluated against the traditional approach based on ZDR measurements collected at 90∘ elevations. Additionally, the method is independently assessed using disdrometers located near the radar sites. The results showed a reasonable agreement between disdrometer-derived and radar-calibrated ZDR measurements.

Characterization of TiO2 and an as-prepared TiO2/SiO2 composite and their photocatalytic performance for the reduction of low-concentration N-NO3- in water.

Excessive N-NO3- water pollution has become a widespread and serious problem that threatens human and ecosystem health. Here, a TiO2/SiO2 composite photocatalyst was prepared via the sol-gel/hydrothermal method. TiO2 and TiO2/SiO2 were characterized by X-ray diffraction (XRD), UV-Vis differential reflectance spectroscopy (DRS), Fourier infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Afterward, the photocatalytic performance of TiO2 and TiO2/SiO2 to reduce low nitrate concentrations (30 mgN L-1) under UV light was evaluated and the effects of different factors on this process were investigated, after which the reaction conditions were optimized. Removal rates of up to 99.93% were achieved at a hole scavenger (formic acid) concentration of 0.6mL L-1, a CO2 flow rate of 0.1 m3h-1, and a TiO2 concentration of 0.9g L-1. In contrast, TiO2/SiO2 at a 1.4g L-1 concentration and a TiO2 load rate of 40% achieved a removal rate of 83.48%, but with more than 98% of nitrogen generation rate. NO2- and NH4+ were the minor products, whereas N2 was the main product.

Blue phosphorene on Au(111) as a decoupling layer for organic epitaxially grown films

Blue phosphorene (BlueP) is considered as a promising two-dimensional (2D) material for future-(opto)electronic applications. Monolayer BlueP is often fabricated on Au(111) single-crystal surfaces. It has been suggested that small P domains form a lateral network with Au adatoms. Previous studies attempting to use BlueP/Au(111) as a substrate for the deposition of fullerene indicated that the former is susceptible to structural deterioration, unlike most other 2D materials in this regard. Here, we investigate 3,4:9,10-perylenetetracarboxylic dianhydride (PTCDA) monolayers and multilayer films deposited on BlueP/Au(111). We monitor the film growth in real time using in situ optical differential reflectance spectroscopy with the substrate kept either at room temperature or at $\ensuremath{\approx}120{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$. Furthermore, we examine the epitaxial alignment between PTCDA and BlueP by means of distortion-corrected low-energy electron diffraction and low-temperature scanning tunneling microscopy. Our data clearly reveal that PTCDA exhibits a highly ordered monolayer structure with a herringbone packing motif, whereas the domain orientations differ from all previously reported structures of PTCDA directly on Au(111). Importantly, we find no indications for adsorption-induced reordering or degradation of BlueP/Au(111). At elevated temperatures, PTCDA is observed to form multilayer islands covering only a fraction of the available PTCDA monolayer surface on BlueP/Au(111), and this Stranski-Krastanov growth mode bears similarities to literature results for PTCDA multilayers on pristine coinage metal surfaces.