Thick-film Devices Research Articles

Modulating Aggregation Behavior by Ternary Strategies for Efficient and Stable Thick-Film Organic Solar Cells.

Functional third components targeted to improve a specific property of organic solar cells is an effective strategy. However, introducing a third component to simultaneously improve efficiency and stability and achieve good performance in thick-film devices has rarely been reported. Herein, low diffusion third components IDCN and ID2CN are reported to achieve a power conversion efficiency (PCE)of 18.08% and a high short-circuit current (J SC)of 27.82mAcm-2, one of the highest values based on PM6:Y6. They increase light harvesting in the range of 400-500nm while enhancing energy transfer via Förster resonance energy transfer (FRET). A tightly ordered molecular arrangement is achieved by modulating the preaggregation and film formation kinetics of Y6, which enhance exciton dissociation and charge transport. Moreover, the low-diffusion third component can effectively restrict the diffusion of Y6 to improve the morphology stability, and the T90 lifetime is increased from 689 to 1545h. In 300nm thick-film devices, PM6:ID2CN:Y6 achieves a PCE of 15.01%, much higher than PM6:Y6's 12.83%, demonstrating the great potential of ID2CN in thick-film devices.

High Performance As-Cast Organic Solar Cells Enabled by a Refined Double-Fibril Network Morphology and Improved Dielectric Constant of Active Layer.

High performance organic solar cells (OSCs) are usually realized by using post-treatment and/or additive, which can induce the formation of metastable morphology, leading to unfavorable device stability. In terms of the industrial production, the development of high efficiency as-cast OSCs is crucially important, but it remains a great challenge to obtain appropriate active layer morphology and high power conversion efficiency (PCE). Here, efficient as-cast OSCs are constructed via introducing a new polymer acceptor PY-TPT with a high dielectric constant into the D18:L8-BO blend to form a double-fibril network morphology. Besides, the incorporation of PY-TPT enables an enhanced dielectric constant and lower exciton binding energy of active layer. Therefore, efficient exciton dissociation and charge transport are realized in D18:L8-BO:PY-TPT-based device, affording a record-high PCE of 18.60% and excellent photostability in absence of post-treatment. Moreover, green solvent-processed devices, thick-film (300nm) devices, and module (16.60 cm2) are fabricated, which show PCEs of 17.45%, 17.54%, and 13.84%, respectively. This work brings new insight into the construction of efficient as-cast devices, pushing forward the practical application of OSCs.

Strain regulates the photovoltaic performance of thick-film perovskites

Perovskite photovoltaics, typically based on a solution-processed perovskite layer with a film thickness of a few hundred nanometres, have emerged as a leading thin-film photovoltaic technology. Nevertheless, many critical issues pose challenges to its commercialization progress, including industrial compatibility, stability, scalability and reliability. A thicker perovskite film on a scale of micrometres could mitigate these issues. However, the efficiencies of thick-film perovskite cells lag behind those with nanometre film thickness. With the mechanism remaining elusive, the community has long been under the impression that the limiting factor lies in the short carrier lifetime as a result of defects. Here, by constructing a perovskite system with extraordinarily long carrier lifetime, we rule out the restrictions of carrier lifetime on the device performance. Through this, we unveil the critical role of the ignored lattice strain in thick films. Our results provide insights into the factors limiting the performance of thick-film perovskite devices.

Ameliorated trap density and energetic disorder via a strengthened intermolecular interaction strategy to construct efficient non-halogenated organic solar cells

The efficiency of non-halogenated organic solar cells is improved from 17.1% to 19.4% after dibenzyl ether (DBE) additive treatment. More strikingly, the thick-film devices achieved a champion efficiency of 17.4%.

High-Performance Paper-Based Thermoelectric Generator from Cu2SnS3 Nanocubes and Bulk-Traced Bismuth.

Flexible paper-based thermoelectric generators (PTEGs) have drawn significant interest in recent years due to their various advantages such as flexibility, adaptability, environment friendliness, low cost, and easy fabrication process. However, the reported PTEG's output performance still lags behind the performance of other flexible devices as it is not so easy to obtain a compact film on a paper-based substrate with desirable power output with the standard thermoelectric (TE) materials that have been previously utilized. In this direction, Cu2SnS3 (CTS), an earth-abundant, ternary sulfide, can be a good choice p-type semiconductor, when paired with a suitable n-type TE material. In this article, CTS nanocubes are synthesized via a simple hot injection method and a thick film device on emery paper was prepared and optimized. Furthermore, a flexible, 20-pair PTEG is fabricated with p-type CTS legs and traced and pressed n-type bismuth legs assembled using Kapton tape that produced a significantly high output power of 2.18 μW (output power density ∼0.85 nW cm-2 K-1) for a temperature gradient of ΔT = 80 K. The TE properties are also supported by finite element simulation. The bending test conducted for the PTEG suggests device stability for up to 800 cycles with <0.05% change in the internal resistance. A proof-of-concept field-based demonstration for energy harvesting from waste heat of a motorbike exhaust is shown recovering an output power of ∼42 nW for ΔT = 20 K, corroborating the experimental and theoretical results.

Over 18% Efficiency Ternary Organic Solar Cells with 300nm Thick Active Layer Enabled by an Oligomeric Acceptor.

The development of high-efficiency thickness-insensitive organic solar cells (OSCs) is crucially important for the mass production of solar panels. However, increasing the active layer thickness usually induces a substantial loss in efficiency. Herein, a ternary strategy in which an oligomer DY-TF is incorporated into PM6:L8-BO system as a guest component is adopted to break this dilemma. The S···F intramolecular noncovalent interactions in the backbone endow DY-TF with a high planarity. Upon the addition of DY-TF, the crystallinity of the blend is effectively improved, leading to increased charge carrier mobility, which is highly desirable in the fabrication of thick-film devices. As a result, thin-film PM6:L8-BO:DY-TF-based device (110nm) shows a power conversion efficiency (PCE) of 19.13%. Impressively, when the active layer thickness increases to 300nm, an efficiency of 18.23% (certified as 17.8%) is achieved, representing the highest efficiency reported for 300 nm thick OSCs thus far. Additionally, blade-coated thick device (300nm) delivers a promising PCE of 17.38%. This work brings new insights into the construction of efficient OSCs with high thickness tolerance, showing great potential for roll-to-roll printing of large-area solar cells.

Low voltage thick-film electroluminescent device with evaporated ZnS:Mn and spin coated BaTiO3 dielectric layer

In a thick-dielectric electroluminescent (TDEL) device, which is a variation of thin-film electroluminescent devices, one of the insulation layers is replaced by a thick-film dielectric layer. High brightness and reliability are the features of TDEL owing to a higher withstanding voltage of the thick-film dielectric layer. This paper presents a new type of TDEL with a bottom emission structure. The thick-film dielectric layer was manufactured by spin coating using an ink material, which is a mixture of BaTiO3 powder and a binder resin. The thicknesses of the phosphor and dielectric layers were minimized to reduce the operating voltage. A threshold voltage as low as 50 V and a maximum luminance of 1000 cd/m2 were obtained at 60 V.

Electronic Component Identification using Voice Recognition

Abstract: Any fundamental discrete device or physical object in an electronic system that affects electrons or the fields around them is referred to as an electronic component. Electrical elements, which are conceptual, should not be confused with electronic components, the majority of which are industrial goods that are only available in a single form. Abstractions used to represent idealised electronic parts and components. There are numerous electrical terminals or leads on electronic components. To build an electronic circuit with a specific purpose (such as an amplifier, radio receiver, or oscillator), these leads link to other electrical components, frequently by wire. Basic electronic components can be integrated inside of discrete packages like semiconductor integrated circuits, hybrid integrated circuits, or thick film devices, as well as arrays or networks of similar components. The list of electrical components that follows concentrates on their discrete form and treats such bundles as independent components

In-situ construction of direct Z-scheme NiO/Bi2MoO6 heterostructure arrays with enhanced room temperature ether sensing properties under visible light irradiation

Light irradiation has emerged as a promising strategy to promote room temperature sensing of resistive-type semiconductor gas sensors recently. However, high recombination rate of photo-generated carriers and poor visible light response of conventional semiconductor sensing materials have greatly limited the further performance improvement. It is urgent to develop gas sensing materials with high photo-generated carrier separation efficiency and excellent visible light response. Herein, a novel direct Z-scheme NiO/Bi2MoO6 heterostructure arrays were designed and in-situ constructed on alumina flat substrate to form thin film sensors, which realized excellent room temperature gas response towards ether under irradiation of visible light for the first time, together with excellent stability and selectivity. Based on density functional theory calculation and experimental characterization, it was demonstrated that the construction of Z-scheme heterostructure could greatly promote the separation of photo-generated carriers and adsorption of ether. Moreover, the excellent visible light response characteristics of NiO/Bi2MoO6 could improve the utilization of visible light. In addition, the in-situ construction of array structure could avoid a series of problems caused by the conventional thick film devices. The work not only provides a promising guideline for Z-scheme heterostructure arrays in promoting the room temperature sensing performance of semiconductors gas sensors under visible light irradiation, but also clarifies the gas sensing mechanism of Z-scheme heterostructure at the atomic and electronic level.

Fullerene-Liquid-Crystal-Induced Micrometer-Scale Charge-Carrier Diffusion in Organic Bulk Heterojunction.

The short charge-carrier diffusion length (LD ) (100-300nm) in organic bulk heterojunction (BHJ) impedes the further improvement in power conversion efficiency (PCE) of organic solar cells (OSCs), especially for thick-film (>400nm) devices matching with industrial solution processing. Here a facile method is developed to efficiently increase LD and then improve PCEs of OSCs via introducing a fullerene liquid crystal, F1, into the active layer. F1 combines the inherent high electron mobility of fullerene and strong self-assembly capacity of liquid crystal, providing a fast channel for charge-carrier transportand reducing energetic disorder and trap density in BHJ film via enhancing crystallization. Typically, in PM6:Y6:F1 BHJ, the enhanced charge-carrier mobility (>10-2 cm-2 V-1 s-1 ) and prolonged charge-carrier lifetime (55.3 µs) are acquired to realize the record LD of 1.6 or 2.4µm for electron or hole, respectively, which are much higher than those of the PM6:Y6 binary sample and comparable to or even better than those values reported for some inorganic/hybrid materials, such as CuInx Ga(1- x ) Se2 (CIGS) and perovskite thin films. Benefitting from the micrometer-scale LD , the PM6:Y6:F1 ternary OSCs sustain a remarkable PCE of 15.23% with the active layer thickness approaching 500nm.

Importance of Electric-Field-Independent Mobilities in Thick-Film Organic Solar Cells.

In organic solar cells (OSCs), a thick active layer usually yields a higher photocurrent with broader optical absorption than a thin active layer. In fact, a ∼300 nm thick active layer is more compatible with large-area processing methods and theoretically should be a better spot for efficiency optimization. However, the bottleneck of developing high-efficiency thick-film OSCs is the loss in fill factor (FF). The origin of the FF loss is not clearly understood, and there a direct method to identify photoactive materials for high-efficiency thick-film OSCs is lacking. Here, we demonstrate that the mobility field-dependent coefficient is an important parameter directly determining the FF loss in thick-film OSCs. Simulation results based on the drift-diffusion model reveal that a mobility field-dependent coefficient smaller than 10-3 (V/cm)-1/2 is required to maintain a good FF in thick-film devices. To confirm our simulation results, we studied the performance of two ternary bulk heterojunction (BHJ) blends, PTQ10:N3:PC71BM and PM6:N3:PC71BM. We found that the PTQ10 blend film has weaker field-dependent mobilities, giving rise to a more balanced electron-hole transport at low fields. While both the PM6 blend and PTQ10 blend yield good performance in thin-film devices (∼100 nm), only the PTQ10 blend can retain a FF = 74% with an active layer thickness of up to 300 nm. Combining the benefits of a higher JSC in thick-film devices, we achieved a PCE of 16.8% in a 300 nm thick PTQ10:N3:PC71BM OSC. Such a high FF in the thick-film PTQ10 blend is also consistent with the observation of lower charge recombination from light-intensity-dependent measurements and lower energetic disorder observed in photothermal deflection spectroscopy.

Multiphase Morphology with Enhanced Carrier Lifetime via Quaternary Strategy Enables High-Efficiency, Thick-Film, and Large-Area Organic Photovoltaics.

With the continuous breakthrough of the efficiency oforganic photovoltaics (OPVs), their practical applications are on the agenda. However, the thickness tolerance and upscaling in recently reported high-efficiency devices remains challenging. In this work, the multiphase morphology and desired carrier behaviors are realized by utilizing a quaternary strategy. Notably, the exciton separation, carrier mobility, and carrier lifetime are enhanced significantly, the carrier recombination and the energy loss (Eloss ) are reduced, thus beneficial for a higher short-circuit density (JSC ), fill factor (FF), and open-circuit voltage (VOC ) of the quaternary system. Moreover, the intermixing-phase size is optimized, which is favorable for constructing the thick-film and large-area devices. Finally, the device with a 110nm-thick active layer shows an outstanding power conversion efficiency (PCE) of 19.32% (certified 19.35%). Furthermore, the large-area (1.05 and 72.25 cm2 ) devices with 110nm thickness present PCEs of 18.25% and 12.20%, and the device with a 305nm-thick film (0.0473 cm2 ) delivers a PCE of 17.55%, which are among the highest values reported. The work demonstrates the potential of the quaternary strategy for large-area and thick-film OPVs and promotes the practical application of OPVs in the future.

ZnO/MoO3 Heterojunction Thick Films to Detect ppb Level Volatile Organic Compounds

The development of a fast, stable metal oxide-based VOC sensor for the detection of trace-level ppb concentrations, remains a challenge. Recently, many composite materials have been investigated to try and develop sensors with these characteristics. Here, we report on the development of ZnO/MoO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> heterojunction thick film devices, fabricated by a spin-coating technique, to detect a wide range of VOCs at application relevant ppb level concentrations. For comparison, pristine ZnO and pristine MoO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> devices were also fabricated. Sensors were tested at different temperatures and resulting in an optimum temperature of 380°C. The sensors were tested towards 11 different VOCs at ppb concentrations. Of all the sensors tested, the heterojunction device showed the highest response to VOCs, with the highest sensitivity towards 200 ppb of ethanol (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> /R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> = 12.84). The results compared well with the pristine materials, with the response of the ZnO material being 6 times smaller and MoO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 10 times smaller compared to their heterojunction counterpart. The response times of the heterojunction device were also faster, at around 30 sec compared with 120 sec for pristine materials.

Regulation of Crystallinity and Vertical Phase Separation Enables High‐Efficiency Thick Organic Solar Cells

AbstractThick film organic solar cells have great potential for preparing large‐area devices in the future. However, unsuitable vertical donor/acceptor distribution, poor crystallinity of materials, and voltage losses remain unclear, limiting the performance of thick film devices. Here, a target ternary strategy by introducing a nematic liquid crystalline small molecule donor BTR‐Cl into the PM6:Y6 host system is used to reduce the performance degradation caused by the increase of active layer thickness. By incorporating 10% BTR‐Cl into the blend film, the voltage loss is minimized in both thin and thick ternary devices. Moreover, the power conversion efficiency of the ternary device is maintained at 15.28% compared to 12.94% of binary devices with an active layer thickness of 300 nm. It is benefited from the optimized crystallization behavior and more suitable vertical phase distribution driven by differences in miscibility between components. While ensuring sufficient phase separation, the charge transport is improved, it also prompts the balance of charge transport and reduces the non‐radiative recombination. This work demonstrates that the use of the third component to enhance the crystallization of the active layer and improve the vertical phase distribution is an effective method to build thick films for future large‐scale printing techniques.

Silicone encapsulation of thin-film SiO x , SiO x N y and SiC for modern electronic medical implants: a comparative long-term ageing study

Objective. Ensuring the longevity of implantable devices is critical for their clinical usefulness. This is commonly achieved by hermetically sealing the sensitive electronics in a water impermeable housing, however, this method limits miniaturisation. Alternatively, silicone encapsulation has demonstrated long-term protection of implanted thick-film electronic devices. However, much of the current conformal packaging research is focused on more rigid coatings, such as parylene, liquid crystal polymers and novel inorganic layers. Here, we consider the potential of silicone to protect implants using thin-film technology with features 33 times smaller than thick-film counterparts. Approach. Aluminium interdigitated comb structures under plasma-enhanced chemical vapour deposited passivation (SiO x , SiO x N y , SiO x N y + SiC) were encapsulated in medical grade silicones, with a total of six passivation/silicone combinations. Samples were aged in phosphate-buffered saline at 67 ∘C for up to 694 days under a continuous ±5 V biphasic waveform. Periodic electrochemical impedance spectroscopy measurements monitored for leakage currents and degradation of the metal traces. Fourier-transform infrared spectroscopy, x-ray photoelectron spectroscopy, focused-ion-beam and scanning-electron- microscopy were employed to determine any encapsulation material changes. Main results. No silicone delamination, passivation dissolution, or metal corrosion was observed during ageing. Impedances greater than 100 GΩ were maintained between the aluminium tracks for silicone encapsulation over SiO x N y and SiC passivations. For these samples the only observed failure mode was open-circuit wire bonds. In contrast, progressive hydration of the SiO x caused its resistance to decrease by an order of magnitude. Significance. These results demonstrate silicone encapsulation offers excellent protection to thin-film conducting tracks when combined with appropriate inorganic thin films. This conclusion corresponds to previous reliability studies of silicone encapsulation in aqueous environments, but with a larger sample size. Therefore, we believe silicone encapsulation to be a realistic means of providing long-term protection for the circuits of implanted electronic medical devices.

Eutectic phase behavior induced by a simple additive contributes to efficient organic solar cells

Introducing a small amount of high boiling point solvent additive has been widely regarded as a feasible method to optimize the active layer morphology of organic solar cells (OSCs). However, current additives are initially developed for fullerene based OSCs and the development of additive engineering is lagging behind the development of non-fullerene acceptor based OSCs. Here, a simple and versatile solid additive, 1,4-diiodobenzene (DIB), is introduced to the non-fullerene OSCs. Due to the formation of a eutectic phase between the additive and the non-fullerene acceptor, a desired microstructure with tighter molecular stacking and more ordered molecular arrangement is achieved. As a result, DIB treated OSCs display significantly enhanced performance with a power conversion efficiency (PCE) of 17.72% for ternary device, 17.36% for binary device and 15.03% for thick-film (300 nm) device. Additional advantages of the DIB treatment include excellent device stability, toleration of a wide additive concentration range, and versatility in both polymer and small molecule OSCs. The results highlight the importance of additive engineering in high-performance OSCs and demonstrate the significance of supramolecular interactions.

A Benzo[1,2-b:4,5-c']Dithiophene-4,8-Dione-Based Polymer Donor Achieving an Efficiency Over 16.

It is of great significance to develop efficient donor polymers during the rapid development of acceptor materials for nonfullerene bulk-heterojunction (BHJ) polymer solar cells. Herein, a new donor polymer, named PBTT-F, based on a strongly electron-deficient core (5,7-dibromo-2,3-bis(2-ethylhexyl)benzo[1,2-b:4,5-c']dithiophene-4,8-dione, TTDO), is developed through the design of cyclohexane-1,4-dione embedded into a thieno[3,4-b]thiophene (TT) unit. When blended with the acceptor Y6, the PBTT-F-based photovoltaic device exhibits an outstanding power conversion efficiency (PCE) of 16.1% with a very high fill factor (FF) of 77.1%. This polymer also shows high efficiency for a thick-film device, with a PCE of ≈14.2% being realized for an active layer thickness of 190 nm. In addition, the PBTT-F-based polymer solar cells also show good stability after storage for ≈700 h in a glove box, with a high PCE of ≈14.8%, which obviously shows that this kind of polymer is very promising for future commercial applications. This work provides a unique strategy for the molecular synthesis of donor polymers, and these results demonstrate that PBTT-F is a very promising donor polymer for use in polymer solar cells, providing an alternative choice for a variety of fullerene-free acceptor materials for the research community.

A perylene diimide-containing acceptor enables high fill factor in organic solar cells.

A new non-fullerene acceptor PDFC is prepared by introducing perylene diimide into the core of an A-DA'D-A architecture. Due to the large conjugation and electron-deficient ability of perylene diimide, PDFC shows strong absorption, suitable energy levels and favorable face-on packing. The optimal device realizes a PCE of 12.56% with one of the highest fill factors (81.3%). A PCE of 9.66% is obtained in a 570 nm thick-film device based on PDFC.

Achieving Efficient Thick Film All-polymer Solar Cells Using a Green Solvent Additive

Advances in organic photovoltaic technologies have been geared toward industrial high-throughput printing manufacturing, which requires insensitivity of photovoltaic performance regarding to the light-harvesting layer thickness. However, the thickness of light-harvesting layer for all polymer solar cells (all-PSCs) is often limited to about 100 nm due to the dramatically decreased fill factor upon increasing film thickness, which hampers the light harvesting capability to increase the power conversion efficiency, and is unfavorable for fabricating large-area devices. Here we demonstrate that by tuning the bulk heterojunction morphology using a non-halogenated solvent, cyclopentyl methyl ether, in the presence of a green solvent additive of dibenzyl ether, the power conversion efficiency of all-PSCs with photoactive layer thicknesses of over 500 nm reached an impressively high value of 9%. The generic applicability of this green solvent additive to boost the power conversion efficiency of thick-film devices is also validated in various bulk heterojunction active layer systems, thus representing a promising approach for the fabrication of all-PSCs toward industrial production, as well as further commercialization.

Preparation of layered perovskite-type cuprate thick-film electrode by electrophoretic deposition method and its nitrite-ion sensing properties

Detection of nitrite-ion has become very important for various industrial fields due to its wide application range such as food additives and a rust preventive agent for steels. In this study, we attempted at developing an advanced method to produce layered perovskite-type cuprates based thick-film device for highly sensitive electrochemical sensor for nitrite-ion with a capacity of wide concentration range. Here, layered perovskite-type oxide powders could be synthesized by a polymer precursor method which was deposited on alumina supports with gold electrode by an electrophoretic deposition method. The sensor performance was measured by an amperometric method for nitrite-ion detection. It was found that the Gd2CuO4-based electrode showed fast and good linear responses to nitrite-ion for a wide range of concentration.