Disorder and Transport Properties of In3SbTe2 – an X-ray, Neutron and Electron Diffraction Study

Quenched metastable In3SbTe2 was investigated by X-ray and neutron powder diffraction as well as by single-crystal X-ray diffraction. The average structure corresponds to the rocksalt type, the anion position being occupied by antimony and tellurium. Neutron data indicate no antisite disorder of indium and antimony. The compound is a high-temperature phase that can be quenched to yield a metastable compound at ambient temperature which, upon heating, decomposes at ca. 320 °C into InSb and InTe. Diffuse scattering in reconstructed X-ray and selected area electron diffraction patterns indicates local distortions of the crystal structure due to static atom displacement along from the average positions, caused by the different size of the anions, but no superstructure. The electrical conductivity of In3SbTe2 is 3.2 × 104 S·cm–1 at 25 °C, the temperature characteristics correspond to metallic behavior. Consequently, the thermal conductivity is also rather high. The decomposition into InSb and InTe reduces the electrical conductivity by a factor of 3 in heterogeneous microstructures

In Situ Studies of Solvent Additive Effects on the Morphology Development during Printing of Bulk Heterojunction Films for Organic Solar Cells

The development of polymer morphology and crystallinity of printed bulk heterojunction (BHJ) films doped with the different solvent additives 1,8‐diiodooctane (DIO) or diphenyl ether (DPE) is investigated with in situ grazing‐incidence small/wide‐angle X‐ray scattering. The solvent additives, having different boiling points, lead to a different film drying behavior and morphology growth states in the BHJ films of the benzothiadiazole‐based polymer (PPDT2FBT) and [6,6]‐phenyl‐C$_{71}$‐butyric acid methyl ester (PC$_{71}$BM). The phase demixing in the printed films is changing over time along with solvent evaporation. Polymer domains start aggregating to form larger domains in the liquid–liquid phase, while phase separation mainly occurs in the liquid–solid phase. The present work provides a profound insight into the morphology development of printed BHJ films doped with different solvent additives, which is particularly important for the large‐scale fabrication of organic photovoltaics

In Situ Studies of Solvent Additive Effects on the Morphology Development during Printing of Bulk Heterojunction Films for Organic Solar Cells

The development of polymer morphology and crystallinity of printed bulk heterojunction (BHJ) films doped with the different solvent additives 1,8‐diiodooctane (DIO) or diphenyl ether (DPE) is investigated with in situ grazing‐incidence small/wide‐angle X‐ray scattering. The solvent additives, having different boiling points, lead to a different film drying behavior and morphology growth states in the BHJ films of the benzothiadiazole‐based polymer (PPDT2FBT) and [6,6]‐phenyl‐C$_{71}$‐butyric acid methyl ester (PC$_{71}$BM). The phase demixing in the printed films is changing over time along with solvent evaporation. Polymer domains start aggregating to form larger domains in the liquid–liquid phase, while phase separation mainly occurs in the liquid–solid phase. The present work provides a profound insight into the morphology development of printed BHJ films doped with different solvent additives, which is particularly important for the large‐scale fabrication of organic photovoltaics

In Situ Printing: Insights into the Morphology Formation and Optical Property Evolution of Slot‐Die‐Coated Active Layers Containing Low Bandgap Polymer Donor and Nonfullerene Small Molecule Acceptor

Printing of active layers for high‐efficiency organic solar cells with the slot‐die coating technique can overcome the challenge of upscaling, which will be needed for organic photovoltaics on its way to marketability. The morphology of a bulk‐heterojunction organic solar cell has a very high impact on its power conversion efficiency. Therefore, it is of particular importance to understand the mechanisms of structure formation during printing of active layers to enable further optimization of the solar cell performance and upscaling of the production process. Meniscus‐guided slot‐die coating of the blend of a low bandgap conjugated polymer donor with benzodithiophene units PBDB‐T‐SF and the nonfullerene small molecule acceptor IT‐4F is studied in situ with optical microscopy, Ultraviolet–visible spectroscopy, and grazing incidence small angle X‐ray scattering. The structure formation is followed from the liquid to the final dry film state. Thereby, five regimes of morphology formation are determined. The morphological evolution in the printed active layer is correlated to changing optical properties of the thin film. In the final dry film, polymer domains of several tens of nanometers are observed, which will be favorable for application in high‐efficiency organic solar cells

Effect of Solvent Additives on the Morphology and Device Performance of Printed Nonfullerene Acceptor Based Organic Solar Cells

Printing of active layers of high-efficiency organic solar cells and morphology control by processing with varying solvent additive concentrations are important to realize realworld use of bulk-heterojunction photovoltaics as it enables both up-scaling and optimization of the device performance. In this work, active layers of the conjugated polymer with benzodithiophene units PBDB-T-SF and the nonfullerene small molecule acceptor IT-4F are printed using meniscus guided slot-die coating. 1,8-Diiodooctane (DIO) is added to optimize the power conversion efficiency (PCE). The effect on the inner nanostructure and surface morphology of the material is studied for different solvent additive concentrations with grazing incidence small-angle X-ray scattering (GISAXS), grazing incidence wide-angle X-ray scattering (GIWAXS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Optical properties are studied with photoluminescence (PL), UV/vis absorption spectroscopy, and external quantum efficiency (EQE) measurements and correlated to the corresponding PCEs. The addition of 0.25 vol % DIO enhances the average PCE from 3.5 to 7.9%, whereas at higher concentrations the positive effect is less pronounced. A solar cell performance of 8.95% is obtained for the best printed device processed with an optimum solvent additive concentration. Thus, with the largescale preparation method printing similarly well working solar cells can be realized as with the spin-coating method

An experiment for novel material thin-film solar cell characterization on sounding rocket flights

Novel material thin-film solar cells are promising alternatives to conventional solar cells for future space applications. Previous terrestrial investigations have shown promising stability under simulated space conditions, pioneering the next step to test these solar cells under space conditions. Here, we present the sounding rocket experiment OHSCIS to characterize the electronic behavior of Organic and Hybrid Solar Cells In Space (OHSCIS). The mechanical and electronic design aims at maximizing the rate of data collection and the fail-safety for high scientific output with precise measurements. The maiden flight onboard the MAPHEUS-8 proved the experimental concept to be successful and produced valuable results for the operation and behavior of perovskite and organic solar cells in space

Readily available titania nanostructuring routines based on mobility and polarity controlled phase separation of an amphiphilic diblock copolymer

The amphiphilic diblock copolymer polystyrene-block-polyethylene oxide is combined with sol–gel chemistry to control the structure formation of blade-coated foam-like titania thin films. The influence of evaporation time before immersion into a poor solvent bath and polarity of the poor solvent bath are studied. Resulting morphological changes are quantified by scanning electron microscopy (SEM) and grazing incidence small angle X-ray scattering (GISAXS) measurements. SEM images surface structures while GISAXS accesses inner film structures. Due to the correlation of evaporation time and mobility of the polymer template during the phase separation process, a decrease in the distances of neighboring titania nanostructures from 50 nm to 22 nm is achieved. Furthermore, through an increase of polarity of an immersion bath the energetic incompatibility of the hydrophobic block and the solvent can be enhanced, leading to an increase of titania nanostructure distances from 35 nm to 55 nm. Thus, a simple approach is presented to control titania nanostructure in foam-like films prepared via blade coating, which enables an easy upscaling of film preparation

Spray‐Coating Magnetic Thin Hybrid Films of PS‐ b ‐PNIPAM and Magnetite Nanoparticles

Spray coating is employed to fabricate magnetic thin films composed of thediblock copolymer polystyrene-block-poly(N-isopropylacrylamide) and Fe3O4magnetic nanoparticles (MNPs) functionalized with hydrophobic coatings.The kinetics of structure formation of the hybrid films is followed in situ withgrazing incidence small angle X-ray scattering during the spray deposition. Togain a better understanding of the influence of MNPs on the overall structureformation, the pure polymer film is also deposited as a reference via an identicalspray protocol. At the initial spraying stage, the hybrid film (containing2 wt% of MNPs) exhibits a faster formation process of a complete film ascompared to the reference. The existence of MNPs depresses the dewettingbehavior of polymer films on the substrate at macroscale and simultaneouslyalters the polymer microphase separation structure orientation fromparallel to vertical. As spraying proceeds, MNPs aggregate into agglomerateswith increasing sizes. After the spray deposition is finished, both samplesgradually reach an equilibrium state and magnetic films with stable structuresare achieved in the end. Superconducting quantum interference deviceinvestigation reveals the superparamagnetic property of the sprayed hybridfilm. Consequently, potential application of sprayed films in fields such asmagnetic sensors or data storage appears highly promising

Comparison of UV Irradiation and Sintering on Mesoporous Spongelike ZnO Films Prepared from PS- b -P4VP Templated Sol–Gel Synthesis

Mesoporous ZnO films with large surface-area-to-volume ratio show great promise in multiple applications, among which solid-state dye-sensitized solar cells (ssDSSCs) have attracted great attention in the field of photovoltaics. An appropriate mesopore size in the nanostructured ZnO films significantly plays an indispensable role in improving the device efficiency that resulted from an efficient penetration of dye molecules and solid hole transport material. In the present work, mesoporous spongelike ZnO films are prepared using sol–gel synthesis templated by a diblock copolymer polystyrene-block-poly(4-vinylpyridine). Two different template removal techniques, ultraviolet (UV) irradiation and high-temperature sintering, are used to compare their respective impact on the pore sizes of the final ZnO thin films. Both the surface morphology and the inner morphology show that mesopores obtained via UV irradiation are smaller as compared to their sintered counterparts. Moreover, increasing the template-to-ZnO precursor ratio is found to further enlarge present mesopores. Accordingly, a strong correlation between the pore sizes of sol–gel synthesized ZnO films and photovoltaic performance of fabricated ssDSSCs is demonstrated. In contrast with the devices fabricated from the UV-irradiated ZnO films, those obtained from sintered samples show >2 times higher efficiency