Donor Layer Research Articles

BIO4: A Dual-Action Nitric Oxide-Releasing Slippery Surface Coating for Extracorporeal Organ Support: First Evaluation at Clinically Relevant Blood Flow Rate for Partial Lung Support

Background: Numerous biomaterials are developed to mitigate untoward effects of blood exposure to foreign surfaces on blood-contacting medical devices, such as extracorporeal life support (ECLS); however, limited testing is performed using clinical blood flow conditions and device components. A liquid infused nitric oxide-releasing (LiNORel) material was developed to prevent surface protein adsorption while eluting nitric oxide (NO) to minimize platelet activation and aggregation. The study objective was to assess LiNORel applied to full-scale ECLS circuit tubing during 6 h ex vivo circulation of porcine blood at a clinically relevant flow rate. We hypothesized that LiNORel reduces thrombus deposition and platelet sequestration versus unmodified tubing. Methods: Heparinized blood (0.75 U/mL) was collected from mechanically ventilated swine (n=9, 45-55kg) with ARDS following polytrauma in an unrelated multi-day ICU study. Blood was divided into circuits with the following (500 mL/circuit): CTRL – unmodified tubing; LI – tubing with liquid infused surface modification; NO – tubing with NOrelease modification; LiNORel – tubing with liquid infused and NO-release modifications. Circuits included a blood reservoir, centrifugal pump, and 2 tubing segments (1 m, 3/8” ID). Circulation was performed for 6 h at 1.5 L/min flow rate. Heparin was sparingly administered to maintain activated clotting times (ACT) of 125-160s. Data included: heparin administered, blood gas, methemoglobin (MetHb) as an indicator of NO toxicity, pump revolutions per minute. At baseline, 3- and 6 h, a blood panel was performed to assess platelet count/activation, thromboelastography, PT, aPTT, fibrinogen, D-dimer, von Willebrand factor (vWF) activity and plasma free hemoglobin. Post-circulation thrombus deposition was analyzed. Data were analyzed for within-group time-dependent changes and between group differences. All tests were two-sided (p<0.05 for significance). Results: Circuits remained patent in all groups with ACT in range. Numerically (n.s.), CTRL received more heparin (100±49 U) to maintain ACT (NO=50±32 U, LI=33±27, LiNORel=47±33 U). There was no group difference in blood gases and MetHb. Numerically, reduction in platelet count at 6 h was greatest in CTRL and least in LiNORel (n.s., Fig 1A). Activated platelets were elevated at 6 h in CTRL vs NO (p=0.013) and LiNORel (p=0.020) (Fig 1B). Numerically, procoagulant platelets were elevated in CTRL (Fig 1C). No group differences in thromboelastography, PT, aPTT and fibrinogen were observed. D-dimer was elevated at 6 h in CTRL (p=0.007) and LI (p=0.027) groups. vWF was elevated at 6 h in CTRL (p=0.001). Clot deposition was minimal and not different between groups. Conclusions: LiNORel reduced platelet activation in this model which utilized a clinically relevant blood flow rate and full-scale circulation tubing for partial lung support. Additional testing in vivo for multi-day duration is ongoing in our laboratory. Figure 1. Platelet count (A), concentration of activated platelets indicated by expression of P-selectin (B) and concentration of procoagulant platelets indicated by phosphatidyl serine expression (C) during 6-hours ex vivo circulation. Circuit tubing consisted of Control (CTRL) – uncoated standard tubing; Nitric Oxide (NO) – tubing with embedded nitric oxide donor; Liquid Infused (LI) – tubing swelled with non-adhesive lubricant layer; Liquid-infused Nitric Oxide Release (LiNORel) – tubing with embedded nitric oxide donor and non-adhesive lubricant layer combination coating. †Indicates significant difference between LiNORel and CTRL. ‡Indicates significant difference between NO and CTRL. *Indicates significant difference within NO group from baseline (BL). **Indicates significant difference within CTRL group from BL. ***Indicates significant difference within LiNORel group from BL. ****Indicates significant difference within LI group from BL. All tests two-sided with p<0.05 for significance.

Enhancement of power conversion efficiency by chlorophyll and carotenoid co-sensitization in the biosolar cells

Photosynthetic pigment-based biosolar cells (BSCs) have attracted much attention over the past few years in the field of artificial photosynthesis. To further improve the power conversion efficiency (PCE) of chlorophyll (Chl)-based bilayer BSCs, co-sensitization effects of three carboxylated chromophores, methyl trans-32-carboxy-pyropheophorbide-a (H2Chl-1), methyl 7-deformyl-7-(trans-carboxyethenyl)-pyropheophorbide-b (H2Chl-2), and β-apo-8′-carotenoic acid (Car) were investigated as H2Chl-1:H2Chl-2, H2Chl-1:Car, and H2Chl-2:Car combinations. The homogeneously co-sensitized mesoporous TiO2 (m-TiO2) layer (TiO2–H2Chl:Car) serves as the photoactive and electron extraction layer, while a Chl-a derivative, zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl) forms J-type self-aggregation film and acts as electron donor layer. The light absorption and electron injection efficiency of the TiO2 sensitized H2Chl-1:Car blends are better than those of other types of co-sensitization after optimizing the blend ratio of each type. The electron absorption spectrum of TiO2–(H2Chl-1:Car) at the best mass ratio of 10:3 (molar ratio of 12:5) showed wider absorption band in 350–450 nm region compared to the spectrum of sole TiO2–(H2Chl-1). The charge transfer resistance was significantly reduced when TiO2–(H2Chl-1:Car) was applied for BSCs. The best PCE of 2.13% was achieved using TiO2–(H2Chl-1:Car = 10:3), which corresponds to 40% increase of PCE compared to the device using TiO2–(H2Chl-1) without Car.

Efficient Semitransparent Layer‐by‐Layer Organic Photovoltaics via Optimizing Wide Bandgap and Narrow Absorption Polymer Layer Thickness

Layer‐by‐layer organic photovoltaics (LbL‐OPVs) are fabricated using wide bandgap polymer D18 with narrow photon harvesting range in visible light region and narrow bandgap small molecular N3 with strong near‐infrared photon harvesting; the only difference is D18 layer thickness adjusted by spin coating speed. A 15.75% power conversion efficiency (PCE) is obtained from the LbL‐OPVs with D18 layer prepared under 7000 round per minute of spin coating condition; the corresponding D18/N3 layers have a 52.06% of average visible transmittance (AVT) in the spectral range from 370 to 740 nm. Based on the optimized D18/N3 layers, semitransparent LbL‐OPVs are built with 1 nm Au/(10, 15, 20 nm) Ag as the top electrode. The PCE and AVT of semitransparent LbL‐OPVs can be simultaneously adjusted by altering Ag layer thickness due to its variable reflectance and conductivity of top electrode dependence on Ag layer thickness. The PCE/AVT of 12.58%/22.81%, 13.80%/15.09%, and 14.85%/9.48% can be individually achieved from the semitransparent LbL‐OPVs with 10, 15, or 20 nm‐thick Ag layer, which should be among the highest values of semitransparent OPVs based on bulk heterojunction or LbL structures. Adjusting donor layer thickness may be an effective method to construct efficient semitransparent LbL‐OPVs.

Magnetic state in the quasi-two-dimensional organic conductor λ−(BEST)2FeCl4 and the path of π−d interaction

Studies of the quasi-two-dimensional organic conductors $\ensuremath{\lambda}\text{\ensuremath{-}}{(D)}_{2}M{\mathrm{Cl}}_{4}$ [$D=\text{donor molecules}$, $M=\mathrm{Ga},\mathrm{Fe}$] have shown that $\ensuremath{\lambda}\text{\ensuremath{-}}{(\mathrm{BETS})}_{2}{\mathrm{GaCl}}_{4}$ [BETS = bis(ethylenedithio)tetraselenafulvalene] undergoes an unconventional superconducting transition and $\ensuremath{\lambda}\text{\ensuremath{-}}{(\mathrm{BETS})}_{2}{\mathrm{FeCl}}_{4}$ undergoes a field-induced superconducting transition. In $\ensuremath{\lambda}$-type salts, the interactions between donor molecules and ${\mathrm{FeCl}}_{4}^{\ensuremath{-}}$ ($\ensuremath{\pi}\text{\ensuremath{-}}d$ interactions) are important. To investigate $\ensuremath{\pi}\text{\ensuremath{-}}d$ interaction, a pair of magnetic $M=\mathrm{Fe}$ and nonmagnetic $M=\mathrm{Ga}$ salts which have the same ground state in the donor layer is desired. However, no such pair has been found, and few experimental studies have considered $\ensuremath{\pi}\text{\ensuremath{-}}d$ interaction paths. $\ensuremath{\lambda}\text{\ensuremath{-}}{(\mathrm{BEST})}_{2}M{\mathrm{Cl}}_{4}$ [BEST = bis(ethylenediseleno)tetrathiafulvalene] are obtained for both anions, and $M=\mathrm{Ga}$ salt shows an antiferromagnetic transition, but the ground state has not been analyzed in $M=\mathrm{Fe}$ salt. We perform x-ray diffraction, magnetic susceptibility measurement, and M\"ossbauer spectroscopy in $\ensuremath{\lambda}\text{\ensuremath{-}}{(\mathrm{BEST})}_{2}{\mathrm{FeCl}}_{4}$. We find that a magnetic transition is observed at around 26 K. The $\ensuremath{\lambda}\text{\ensuremath{-}}{(\mathrm{BEST})}_{2}M{\mathrm{Cl}}_{4}$ system is a system in which both ${\mathrm{FeCl}}_{4}^{\ensuremath{-}}$ and ${\mathrm{GaCl}}_{4}^{\ensuremath{-}}$ salts show antiferromagnetic transitions. In addition, the ethylene motions observed at room temperature are ordered around 108 K, resulting in the establishment of the $\ensuremath{\pi}\text{\ensuremath{-}}d$ interaction path between chalcogens and the anion, and low-field magnetization suggests that the $\ensuremath{\pi}\text{\ensuremath{-}}d$ interaction in $\ensuremath{\lambda}\text{\ensuremath{-}}{(\mathrm{BEST})}_{2}{\mathrm{FeCl}}_{4}$ is smaller than that in $\ensuremath{\lambda}\text{\ensuremath{-}}{(\mathrm{BETS})}_{2}{\mathrm{FeCl}}_{4}$. Our results show that the inner chalcogen of donor molecules is important as the path of the interaction.

An application study of membraneless-gas separation microfluidic paper-based analytical device for monitoring total ammonia in fish pond water using natural reagent.

The membraneless-gas separation microfluidic paper-based analytical device(ML-GSμPAD), consisting of donor, spacer, and acceptor layers, was developed to monitor total ammonia in fish pond water. The principle of the analysis involved the addition of sodium hydroxide solution to the sample zone in the donor layer containing ammonia/ammonium, and the produced ammonia gas diffuses through the spacer to the detection zone in the acceptor layer containing red rose extract to produce a color change from pink to blue corresponding to the ammonia/ammonium concentration. Under optimum conditions, the proposed method provided good linearity of ammonia in the range concentration of 0-100mg L-1 (R2 = 0.9993) with LOD and LOQ of 2.25 and 7.51mg L-1, respectively. This method was successfully applied to fish pond water samples without significant influence of interfering compounds with recoveries in the range of 103-110%, indicating good selectivity and accuracy of the proposed method.

High‐Efficiency Sequential‐Cast Organic Solar Cells Enabled by Dual Solvent‐Controlled Polymer Aggregation

The precise tuning of the active layer morphology to improve organic solar cells (OSCs) efficiency remains a key issue in the field of organic photovoltaics. Herein, a new solution to the above problem is provided by using the dual‐solvent modulated polymer‐assisted sequential spin‐coating method. Herein, the sequential spin‐coated OSCs based on the D18‐Cl/Y6 system are prepared for the first time and an efficiency of 16.38% is obtained, similar to that of bulk heterojunction OSCs. On this basis, the performance is further improved by using a dual solvent to balance the dissolution and crystallization of D18‐Cl, separately optimizing the morphology of the donor layer and allowing the subsequent spin‐coated Y6 solution to penetrate uniformly into the D18‐Cl framework. After the dual‐solvent treatment, the D18‐Cl (CF + CB)/Y6‐based device obtains a power conversion efficiency (PCE) of 17.33% and the D18‐Cl (THF + CB)/Y6‐based device achieves an even better PCE of 17.73%. It is worth noting that no post‐treatment is adopted here and after 2500 h of placement, the efficiency of the aforementioned devices is still 90% of the original. Thus, this work provides a simple method for tuning the film morphology to prepare efficient and stable devices, which is beneficial for future commercial production of OSCs.

Layer-by-Layer Organic Photovoltaic Solar Cells Using a Solution-Processed Silicon Phthalocyanine Non-Fullerene Acceptor.

Silicon phthalocyanines (SiPcs) are promising, inexpensive, and easy to synthesize non-fullerene acceptor (NFA) candidates for all-solution sequentially processed layer-by-layer (LbL) organic photovoltaic (OPV) devices. Here, we report the use of bis(tri-n-butylsilyl oxide) SiPc ((3BS)2-SiPc) paired with poly(3-hexylthiophene) (P3HT) and poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′]dithiophene-4,8-dione))] (PBDB-T) donors in an LbL OPV structure. Using a direct architecture, P3HT/(3BS)2-SiPc LbL devices show power conversion efficiencies (PCEs) up to 3.0%, which is comparable or better than the corresponding bulk heterojunction (BHJ) devices with either (3BS)2-SiPc or PC61BM. PBDB-T/(3BS)2-SiPc LbL devices resulted in PCEs up to 3.3%, with an impressive open-circuit voltage (Voc) as high as 1.06 V, which is among the highest Voc obtained employing the LbL approach. We also compared devices incorporating vanadium oxide (VOx) or poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a hole transporting layer and found that VOx modified the donor layer morphology and led to improved Voc. Probing the composition as a function of film layer depths revealed a similar distribution of active material for both BHJ and LbL structures when using (3BS)2-SiPc as an NFA. These findings suggest that (3BS)2-SiPc is a promising NFA that can be processed using the LbL technique, an inherently easier fabrication methodology for large-area production of OPVs.

High-performance pseudo-bilayer ternary organic solar cells with PC71BM as the third component

PM6/Y6:PC71BM pseudo-bilayer ternary OSCs were prepared. PC71BM enhances light absorption and boosts VOC, and improves the contact between the donor layer and acceptor layer, which improves photovoltaic performance and device stability significantly.

Electronic structure of Li+@C60 adsorbed on methyl-ammonium lead iodide perovskite CH3NH3PbI3 surfaces

Jeon et al. [Angew. Chem., 2018, 57, 4607] showed that air stability for over 1000 hours under light illumination can be achieved in CH3NH3PbI3 perovskite solar cells when Li+ is replaced by Li+@C60 in a dopant material used in the p-type donor layer.

Thermally coupled SHS processes in (Ni + Al)/(Co + Ti)/(Ni + Al) layered system: experimental and theoretical study

The paper focuses on the theoretical and experimental study of the mechanisms of reaction mixture combustion in the ≪chemical oven≫ mode in a three-layer Ni–Al/Ti–Co/Ni–Al sample. Experimental studies were carried out in a reactor in an argon atmosphere at atmospheric pressure and an ambient temperature of 298 K on rectangular samples pressed from Ni–Al and Ti–Co powder mixtures in the form of a three-layer package. The Ti–Co acceptor layer was in the middle of the sample, and the Ni–Al donor layer was outside. The acceptor layer thickness was varied from 4.3 to 13 mm, while the donor layer thickness (4.7 mm) remained constant. It was found that as the acceptor layer thickness increases, the combustion wave front propagation velocity and reaction initiation temperature decrease, and the maximum temperature in the front remains constant and equal to the melting point of the final product. The time of acceptor layer heating before the reaction increases. The acceptor mixture reaction proceeds in the thermal explosion mode when the thickness of the acceptor layer exceeds that of the donor one. Maximum temperature in this case is higher than the melting point of the final product. The inner layer synthesis modes change with an increase in the acceptor layer thickness: stationary – pulsating – extinction. The mathematical model of the three-layer sample high-temperature synthesis in dimensional variables is constructed taking into account heat transfer with the environment. As a result of experimental studies and numerical calculations, the critical thickness of the inner layer was found to be 15 mm, at which the inner layer combustion becomes impossible at fixed sizes of donor layers. Critical conditions for the combustion wave propagation along the acceptor layer are weakly dependent on the external heating source. The experimental technique and mathematical model of the layered system combustion can be used to assess the critical conditions for the metal composite synthesis in the frontal combustion mode.

Dissection of Barrier Dysfunction in Organoid-Derived Human Intestinal Epithelia Induced by Giardia duodenalis

The protozoa Giardia duodenalis is a major cause of gastrointestinal illness worldwide, but underlying pathophysiological mechanisms remain obscure, partly due to the absence of adequate cellular models. We aimed at overcoming these limitations and recapitulating the authentic series of pathogenic events in the primary human duodenal tissue by using the human organoid system. We established a compartmentalized cellular transwell system with electrophysiological and barrier properties akin to duodenal mucosa and dissected the events leading to G. duodenalis-induced barrier breakdown by functional analysis of transcriptional, electrophysiological, and tight junction components. Organoid-derived cell layers of different donors showed a time- and parasite load-dependent leak flux indicated by collapse of the epithelial barrier upon G. duodenalis infection. Gene set enrichment analysis suggested major expression changes, including gene sets contributing to ion transport and tight junction structure. Solute carrier family 12 member 2 and cystic fibrosis transmembrane conductance regulator-dependent chloride secretion was reduced early after infection, while changes in the tight junction composition, localization, and structural organization occurred later as revealed by immunofluorescence analysis and freeze fracture electron microscopy. Functionally, barrier loss was linked to the adenosine 3',5'-cyclic monophosphate (cAMP)/protein kinase A-cAMP response element-binding protein signaling pathway. Data suggest a previously unknown sequence of events culminating in intestinal barrier dysfunction upon G. duodenalis infection during which alterations of cellular ion transport were followed by breakdown of the tight junctional complex and loss of epithelial integrity, events involving a cAMP/protein kinase A-cAMP response element-binding protein mechanism. These findings and the newly established organoid-derived model to study G. duodenalis infection may help to explore new options for intervening with disease and infection, in particular relevant for chronic cases of giardiasis.

Highly Selective High‐Speed Circularly Polarized Photodiodes Based on π‐Conjugated Polymers

AbstractChiral π‐conjugated molecular systems that are intrinsically sensitive to the handedness of circularly polarized (CP) light potentially allow for miniaturized, low‐cost CP detection devices. Such devices promise to transform several technologies, including biosensing, quantum optics, and communication of data encrypted by exploiting the spin angular momentum of light. Here a simple, bilayer organic photodiode (CP OPD) comprising an achiral π‐conjugated polymer–chiral additive blend as the electron donor layer and an achiral C60 electron acceptor layer is realized. These devices exhibit considerable photocurrent dissymmetry gph, with absolute values as high as 0.85 and dark currents as low as 10 pA. Impressively, they showcase a linear dynamic range of 80 dB, and rise and fall times of ≈7 µs, which significantly outperforms all previously reported CP selective photodetectors. Mechanistically, it is shown that the gph is sensitive to the thickness of both the chiral donor and achiral acceptor layers and that a trade‐off exists between the external quantum efficiency and gph. The fast‐switching speeds of these devices, coupled with their large dynamic range and highly selective response to CP light, opens up the possibility of their direct application in CP sensing and optical communications.

Printed Cu–Ag Phases Using Laser‐Induced Forward Transfer

Laser‐induced forward transfer (LIFT) is an additive manufacturing technique where short laser pulses are focused through a transparent substrate onto a thin, uniform, metal layer jetting micrometer‐scale droplets yielding high‐resolution 3D metal structures. Herein, LIFT printing from multilayered metal donors, and from compositional metal mixtures, is explored and presented. A comprehensive study of this sort has been lacking so far. LIFT printing from Cu–Ag structured donors is thoroughly studied. X‐ray diffraction (XRD) analysis reveals the formation of a metastable Cu–Ag phase reflecting the high cooling rate of the metal droplets. Tuning properties of the printed metal structures is made possible by controlling the pulse width and the donor layers’ properties. Longer pulses (10 ns) jetting from cosputtered donors yield better homogeneity than shorter pulses (1 ns) from donors made of distinct sputtered layers. These homogenic structures also display better resistance to chemical etching. This study opens the door to designing various phases and structures with different electrical and mechanical properties by using LIFT of multimaterials donors.

Multi-Functional Solid Additive Induced Favorable Vertical Phase Separation and Ordered Molecular Packing for Highly Efficient Layer-by-Layer Organic Solar Cells.

Layer-by-layer (LBL) deposition strategy enabling favorable vertical phase distributions has been regarded as promising candidates for constructing high-efficient organic photovoltaic (OPV) cells. However, solid additives with the merits of good stability and reproducibility have been rarely used to fine-tune the morphology of the LBL films for improved efficiency and stability. Herein, hierarchical morphology control in LBL OPV is achieved via a dual functional solid additive. Series of LBL devices are fabricated by introducing the solid additive individually or simultaneously to the donor or acceptor layer to clarify the functions of additives. Additive in the donor layer can facilitate the formation of preferable vertical component distribution, and that in the acceptor layer will enhance the molecular crystallinity for better charge transport properties. The optimized morphology ultimately contributed to high PCEs of 16.4% and 17.4% in the binary and quaternary LBL devices. This reported method provides an alternative way to controllably manipulate the morphology of LBL OPV cells.

Layer‐by‐layered organic solar cells: Morphology optimizing strategies and processing techniques

AbstractThe last decades have witnessed the rapid development and the gradually improved efficiencies of organic solar cells (OSCs), which show great potentials in the fabrication of eco‐friendly and flexible photovoltaic panels. Layer‐by‐layered (LBL) structure via sequential processing of the donor and acceptor layers becomes an advisable option to construct pseudo‐bilayer configurations in OSC active layer. Favorable vertical phase separation and sufficient exciton dissociation interfaces can be simultaneously realized in such aggregation morphology via different processing technologies and strategies. High efficiencies of over 18% in ternary LBL device and 11.9% in LBL‐processed module (11.52 cm2) have been successfully achieved in recent works. Moreover, the unique merits of LBL structure in individual layer processing enable it a promising candidate for large‐scale printing and further industrialization of OSCs. This perspective provides the recent advance of LBL OSCs with the focus on fabrication technologies and strategies for morphology control and also proposes the current thinking and perspective on LBL structures for future development.

Dendritic Interfacial Exciplex Hosts for Solution‐Processed TADF‐OLEDs with Power Efficiency Approaching 100 lm W−1

AbstractTwo kinds of interfacial exciplex hosts formed between a dendritic oligocarbazole donor (H2) and two pyridine‐containing isomeric acceptors (B4PyMPM and B3PyMPM) are developed for solution‐processed thermally activated delayed fluorescent (TADF) organic light‐emitting diodes (OLEDs). The exciplex hosts exhibit small singlet−triplet energy splitting (90–110 meV) and distinct TADF effect which can convert triplet excitons into singlet ones and thus are beneficial for alleviating the triplet annihilation process. Notably, it is found that a small structural variation of acceptor from B4PyMPM (para‐linked pyridyl units) to B3PyMPM (meta‐linked pyridyl units) has a significant effect on enhancing carrier balance between donor and acceptor layers of interfacial exciplex, leading to greatly improved electroluminescent efficiency for the resultant devices. Solution‐processed TADF‐OLEDs based on H2/B3PyMPM interfacial exciplex host achieve the maximum power efficiency (PE) of 95.0 lm W−1 (85.5 cd A−1, 26.4 %), which is much better than that of H2/B4PyMPM devices (69.9 lm W−1) and represents the record PE for solution‐processed TADF‐OLEDs.

Investigation of the Characteristic of Solution‐Processed Tetraphenyldibenzoperiflanthene (DBP) Film and Its Application on Organic Photovoltaic Cells

Solution‐processed tetraphenyldibenzoperiflanthene (DBP) films are prepared with three popular solvents, including chroloform (CF), chrolobenzene (CB), and dichrolobenzene (ODCB). The absorption and photoluminescence (PL) spectra of the DBP solution and DBP film are investigated. The absorption spectra between the DBP film and DBP solution are similar, whereas the PL spectrum shape of the DBP film and DBP solution is completely different, originating from the DBP molecular aggregation in the film, causing conjugate expansion, which results in dimer luminescence. The DBP donor layer at 32 nm prepared from solvent of CF, CB, and ODCB achieves a power conversion efficiency (PCE) of 1.42%, 0.88%, and 0.48%, respectively. The annealing temperature and DBP thickness are optimized; the 32 nm‐thick active layer annealed at 50 °C achieves the highest performance. The CF‐DBP film represents an interpenetrating network morphology, slightly higher roughness and hole mobility, which may be the main contribution to the relatively higher photocurrent than the CB‐DBP and ODCB‐DBP devices. Herein, a simple guidance for preparing solution‐processed DBP films is provided and simultaneously its application on organic photovoltaic cells (OPVs) is expanded.

Organic Semiconductors for Optically Triggered Neural Interfacing: The Impact of Device Architecture in Determining Response Magnitude and Polarity

The use of organic semiconductor devices as photocapacitors is an innovation with promising applications in neural interface technologies, particularly for retinal prosthetics. Here we report the characterization of four distinct photocapacitor device architectures that were fabricated by depositing ultra-thin layers of poly-3-hexylthiophene and C60 fullerene in various combinations on tin-doped indium oxide (ITO) electrodes. We used electrophysiological recordings to measure the intrinsic photoresponse at 470 nm, and also to determine light-induced voltage perturbations in electrolyte solutions interfaced with these semiconductors. We also determined the light-induced intracellular voltage changes in co-cultured sensory neurons. Electrochemical impedance spectroscopy was used to establish the photocapacitive response mechanism of the intracellular changes upon illumination. The largest amplitude photocapacitive response was elicited from a neuron/acceptor-donor bilayer/ITO device architecture, whilst reversing the donor and acceptor layer order enabled a neuron response of the opposite polarity. The photoresponse in the neuron/acceptor/donor/ITO bilayer device configuration was significantly enhanced in both amplitude and time duration by electrical grounding of the indium tin oxide layer. We describe the advantages and limitations of each configuration of these device and discuss pathways towards the creation of optically triggered neural interfaces that do not require an external electrical power supply.

Eco-Friendly Lead-Free Solder Paste Printing via Laser-Induced Forward Transfer for the Assembly of Ultra-Fine Pitch Electronic Components.

Current challenges in printed circuit board (PCB) assembly require high-resolution deposition of ultra-fine pitch components (<0.3 mm and <60 μm respectively), high throughput and compatibility with flexible substrates, which are poorly met by the conventional deposition techniques (e.g., stencil printing). Laser-Induced Forward Transfer (LIFT) constitutes an excellent alternative for assembly of electronic components: it is fully compatible with lead-free soldering materials and offers high-resolution printing of solder paste bumps (<60 μm) and throughput (up to 10,000 pads/s). In this work, the laser-process conditions which allow control over the transfer of solder paste bumps and arrays, with form factors in line with the features of fine pitch PCBs, are investigated. The study of solder paste as a function of donor/receiver gap confirmed that controllable printing of bumps containing many microparticles is feasible for a gap < 100 μm from a donor layer thickness set at 100 and 150 μm. The transfer of solder bumps with resolution < 100 μm and solder micropatterns on different substrates, including PCB and silver pads, have been achieved. Finally, the successful operation of a LED interconnected to a pin connector bonded to a laser-printed solder micro-pattern was demonstrated.

Innovative Implementation of an Alternative Tetrathiafulvene Derivative for Flexible Indium Phthalocyanine Chloride-Based Solar Cells.

Herein, we present the photovoltaic properties of an indium phthalocyanine chloride (InClPc)-based flexible planar heterojunction device, introducing the tetrathiafulvene derivative 4,4′-Dimethyl-5,5′-diphenyltetrathiafulvalene (DMDP-TTF) as the electron donor layer. UV-vis spectroscopy is widely used to characterize the electronic behavior of the InClPc/DMDP-TTF active layer. The interactions between the DMDP-TTF and phthalocyanine are predominantly intermolecular and the result of the aggregation of InClPc. Tauc bands were obtained at 1.41 and 2.8 eV; these energy peaks can result in a charge transfer ascribed to the transition from the DMDP-TTF to π-orbitals that are associated with the phthalocyanine ring or even with the same indium metal center. Conductive carbon (CC) was used for the cathode. Finally, an indium tin oxide (ITO)/InClPc/DMDP-TTF/CC device was fabricated by high-vacuum thermal evaporation onto a flexible substrate and the photovoltaic properties were evaluated. A diode type I-V curve behavior was observed with a photovoltaic response under illumination. A generated photocurrent of 2.25 × 10−2 A/cm2 was measured. A conductivity reduction with the incident photon energy from 1.61 × 10−7 S/cm to 1.43 × 10−7 S/cm is observed. The diode resistance presents two different behaviors with the applied voltage. A VTFL of 5.39 V, trap concentration of 7.74 × 1016 cm−3, and carrier mobility values of ~10−6 cm2/V s were calculated, showing improved characteristics via the innovative implementation of an alternative TTF-derivative, indicating that the DMDP-TTF has a strong interaction at the junction where free available states are increased, thus inducing higher mobilities due to the large number of π-orbitals, which indicates the feasibility of its use in solar cells technology.