Metal Nanowire Networks as Transparent Electrode for Small-Molecule Organic Solar Cells

This work focuses on the development of metal nanowire networks for the use as transparent electrodes in small-molecule organic solar cells. Broad adoption of organic solar cells requires inexpensive roll-to-roll processing on flexible, lightweight substrates. Under these conditions, traditional metal oxide electrodes suffer from significant drawbacks such as brittleness and cost. In contrast, metal nanowire networks provide properties more suitable for high-throughput processing and thus, are investigated here as an alternative. They combine the high-conductivity of metals with the advantage of optical transparency found in aperture-structured networks. The process chain from nanowire deposition to cell integration is examined with silver and copper nanowire material. Two techniques are presented for deposition. While dip-coating is investigated in detail, including a discussion of the most important parameters, spray-coating is demonstrated as an alternative for large area applications. Since the nanowires are barely conductive after deposition, post-treatment steps are used to achieve a performance comparable to standard metal oxide films such as tin-doped indium oxide (ITO). The inherent roughness of nanowire electrodes is addressed by using a conductive polymer as a planarization layer. On top of optimized electrodes, small-molecule organic solar cells are deposited with a UHV thermal evaporation process. Completed cells are tested and performance is found to be comparable to the used standard transparent electrodes. Additionally, a new approach to achieve aligned nanowire network structures is demonstrated. The additional degree of order is used to illustrate optical effects of silver nanowire networks. Furthermore, these aligned networks exhibit anisotropic conductivity. This effect is discussed and simulations are performed to reproduce the observations. The freedom of network design is used to achieve superior conductivity compared to standard random structures.Im Fokus dieser Arbeit steht die Entwicklung von Metall-Nanodraht-Netzwerken für die Anwendung in transparenten Elektroden für organische Solarzellen. Eine breite Verwendung von organischen Solarzellen setzt eine kostengünstige Rolle-zu-Rolle Fertigung auf flexiblen und leichten Substraten voraus. Unter diesen Bedingungen leiden traditionell verwendete Metalloxid-Elektroden unter erheblichen Nachteilen, wie Brüchigkeit und Preis. Im Gegensatz dazu zeigen Metall-Nanodraht-Netzwerke deutlich bessere Eigenschaften und werden deshalb hier als alternative Elektroden untersucht. Die Netzwerke kombinieren die hohe Leitfähigkeit von Metallen mit einer hohen Transmittivität in Folge der netzwerkbedingten Apertur. Die Prozesskette von der Nanodraht-Abscheidung bis zur Zellintegration wird für Silber- und Kupferdrähte untersucht. Zwei Techniken für die Abscheidung werden präsentiert. Ein Tauchverfahren wird detailliert untersucht und die zugehörigen Parameter werden diskutiert. Für große Flächen wird eine Sprühbeschichtung als Alternative aufgezeigt. Da die abgeschiedenen Netzwerke eine schlechte Leitfähigkeit besitzen, sind Nachprozessierungsschritte notwendig um gute Leitfähigkeiten im Bereich von üblichen Elektroden wie Indium-Zinn-Oxid (ITO) zu erreichen. Die Rauheit der Nanodraht-Elektrode wird mit Hilfe einer glättenden Polymerschicht behoben. Auf den optimierten Elektroden werden organische Solarzellen aus kleinen Molekülen in einem thermischen UHV-Prozess abgeschieden. Die Zellen werden getestet und zeigen Eigenschaften vergleichbar zu üblichen transparenten Elektroden. Zusätzlich wird ein neuer Ansatz zur Herstellung von ausgerichteten Netzwerkstrukturen demonstriert. Der zusätzliche Grad an Ordnung wird für die Untersuchung von optischen Effekten an Silberdraht-Netzwerken genutzt. Weiterhin zeigen diese ausgerichteten Netzwerke eine anisotrope Leitfähigkeit. Dieser Effekt wird diskutiert und Simulationen werden durchgeführt, um die Beobachtungen zu verifizieren. Die Freiheit in der Netzwerkstruktur wird für eine Verbesserung der Leitfähigkeit genutzt

2 kirja J. E. I. Walch`ile, Traiecti Batavorum

http://tartu.ester.ee/record=b1880500~S1*es

A spray-coating process for highly conductive silver nanowire networks as the transparent top-electrode for small molecule organic photovoltaics

We present a novel top-electrode spray-coating process for the solution-based deposition of silver nanowires (AgNWs) onto vacuum-processed small molecule organic electronic solar cells. The process is compatible with organic light emitting diodes (OLEDs) and organic light emitting thin film transistors (OLETs) as well. By modifying commonly synthesized AgNWs with a perfluorinated methacrylate, we are able to disperse these wires in a highly fluorinated solvent. This solvent does not dissolve most organic materials, enabling a top spray-coating process for sensitive small molecule and polymer-based devices. The optimized preparation of the novel AgNW dispersion and spray-coating at only 30 °C leads to high performance electrodes directly after the deposition, exhibiting a sheet resistance of 10.0 Ω □−1 at 87.4% transparency (80.0% with substrate). By spraying our novel AgNW dispersion in air onto the vacuum-processed organic p-i-n type solar cells, we obtain working solar cells with a power conversion efficiency (PCE) of 1.23%, compared to the air exposed reference devices employing thermally evaporated thin metal layers as the top-electrode

Multiclass cancer classification in fresh frozen and formalin-fixed paraffin-embedded tissue by DigiWest multiplex protein analysis

Histomorphology and immunohistochemistry are the most common ways of cancer classification in routine cancer diagnostics, but often reach their limits in determining the organ origin in metastasis. These cancers of unknown primary, which are mostly adenocarcinomas or squamous cell carcinomas, therefore require more sophisticated methodologies of classification. Here, we report a multiplex protein profiling-based approach for the classification of fresh frozen and formalin-fixed paraffin-embedded (FFPE) cancer tissue samples using the digital western blot technique DigiWest. A DigiWest-compatible FFPE extraction protocol was developed, and a total of 634 antibodies were tested in an initial set of 16 FFPE samples covering tumors from different origins. Of the 303 detected antibodies, 102 yielded significant correlation of signals in 25 pairs of fresh frozen and FFPE primary tumor samples, including head and neck squamous cell carcinomas (HNSC), lung squamous cell carcinomas (LUSC), lung adenocarcinomas (LUAD), colorectal adenocarcinomas (COAD), and pancreatic adenocarcinomas (PAAD). For this signature of 102 analytes (covering 88 total proteins and 14 phosphoproteins), a support vector machine (SVM) algorithm was developed. This allowed for the classification of the tissue of origin for all five tumor types studied here with high overall accuracies in both fresh frozen (90.4%) and FFPE (77.6%) samples. In addition, the SVM classifier reached an overall accuracy of 88% in an independent validation cohort of 25 FFPE tumor samples. Our results indicate that DigiWest-based protein profiling represents a valuable method for cancer classification, yielding conclusive and decisive data not only from fresh frozen specimens but also FFPE samples, thus making this approach attractive for routine clinical applications

A Smooth Model for the String Group

We construct a model for the string group as an infinite-dimensional Lie group. In a second step we extend this model by a contractible Lie group to a Lie 2-group model. To this end we need to establish some facts on the homotopy theory of Lie 2-groups. Moreover, we provide an explicit comparison of string structures for the two models and a uniqueness result for Lie 2-group models.Comment: 32 pages; v2: uniqueness result for 2-group models added (Th. 6.5), typo in title corrected; v3: construction of basic PU(H)-bundle discussed (Rem. 3.9), final version to appear in IMR

Single Application of Low-Dose, Hydroxyapatite-Bound BMP-2 or GDF-5 Induces Long-Term Bone Formation and Biomechanical Stabilization of a Bone Defect in a Senile Sheep Lumbar Osteopenia Model

Effects of hydroxyapatite (HA) particles with bone morphogenetic BMP-2 or GDF-5 were compared in sheep lumbar osteopenia; in vitro release in phosphate-buffered saline (PBS) or sheep serum was assessed by ELISA. Lumbar (L) vertebral bone defects (Ø 3.5 mm) were generated in aged, osteopenic female sheep ( n = 72; 9.00 ± 0.11 years; mean ± SEM). Treatment was: (a) HA particles (2.5 mg; L5); or (b) particles coated with BMP-2 (1 µg; 10 µg) or GDF-5 (5 µg; 50 µg; L4; all groups n = 6). Untouched vertebrae (L3) served as controls. Three and nine months post-therapy, bone formation was assessed by osteodensitometry, histomorphometry, and biomechanical testing. Cumulative 14-day BMP release was high in serum (76–100%), but max. 1.4% in PBS. In vivo induction of bone formation by HA particles with either growth factor was shown by: (i) significantly increased bone volume, trabecular and cortical thickness (overall increase HA + BMP vs. control close to the injection channel 71%, 110%, and 37%, respectively); (ii) partial significant effects for bone mineral density, bone formation, and compressive strength (increase 17%; 9 months; GDF-5). Treatment effects were not dose-dependent. Combined HA and BMPs (single low-dose) highly augment long-term bone formation and biomechanical stabilization in sheep lumbar osteopenia. Thus, carrier-bound BMP doses 20,000-fold to 1000-fold lower than previously applied appear suitable for spinal fusion/bone regeneration and improved treatment safety

Fuzzy Scalar Field Theory as Matrix Quantum Mechanics

We study the phase diagram of scalar field theory on a three dimensional Euclidean spacetime whose spatial component is a fuzzy sphere. The corresponding model is an ordinary one-dimensional matrix model deformed by terms involving fixed external matrices. These terms can be approximated by multitrace expressions using a group theoretical method developed recently. The resulting matrix model is accessible to the standard techniques of matrix quantum mechanics.Comment: 1+17 pages, 4 figures, minor improvements, version published in JHE

Real‐world outcomes using PD‐1 antibodies and BRAF + MEK inhibitors for adjuvant melanoma treatment from 39 skin cancer centers in Germany, Austria and Switzerland

Abstract Background Programmed death‐1 (PD‐1) antibodies and BRAF + MEK inhibitors are widely used for adjuvant therapy of fully resected high‐risk melanoma. Little is known about treatment efficacy outside of phase III trials. This real‐world study reports on clinical outcomes of modern adjuvant melanoma treatment in specialized skin cancer centers in Germany, Austria and Switzerland. Methods Multicenter, retrospective study investigating stage III–IV melanoma patients receiving adjuvant nivolumab (NIV), pembrolizumab (PEM) or dabrafenib + trametinib (D + T) between 1/2017 and 10/2021. The primary endpoint was 12‐month recurrence‐free survival (RFS). Further analyses included descriptive and correlative statistics, and a multivariate linear‐regression machine learning model to assess the risk of early melanoma recurrence. Results In total, 1198 patients from 39 skin cancer centers from Germany, Austria and Switzerland were analysed. The vast majority received anti PD‐1 therapies (n = 1003). Twelve‐month RFS for anti PD‐1 and BRAF + MEK inhibitor‐treated patients were 78.1% and 86.5%, respectively (hazard ratio [HR] 1.998 [95% CI 1.335–2.991]; p = 0.001). There was no statistically significant difference in overall survival (OS) in anti PD‐1 (95.8%) and BRAF + MEK inhibitor (96.9%) treated patients (p > 0.05) during the median follow‐up of 17 months. Data indicates that anti PD‐1 treated patients who develop immune‐related adverse events (irAEs) have lower recurrence rates compared to patients with no irAEs (HR 0.578 [95% CI 0.443–0.754], p = 0.001). BRAF mutation status did not affect overall efficacy of anti PD‐1 treatment (p > 0.05). In both, anti PD‐1 and BRAF + MEK inhibitor treated cohorts, data did not show any difference in 12‐month RFS and 12‐month OS comparing patients receiving total lymph node dissection (TLND) versus sentinel lymph node biopsy only (p > 0.05). The recurrence prediction model reached high specificity but only low sensitivity with an AUC = 0.65. No new safety signals were detected. Overall, recorded numbers and severity of adverse events were lower than reported in pivotal phase III trials. Conclusions Despite recent advances in adjuvant melanoma treatment, early recurrence remains a significant clinical challenge. This study shows that TLND does not reduce the risk of early melanoma recurrence and should only be considered in selected patients. Data further highlight that variables collected during clinical routine are unlikely to allow for a clinically relevant prediction of individual recurrence risk