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Self-assembled interface monolayers for organic and hybrid electronics
摘要： The state of the art in the field of self-assembled organic interface monolayers widely used in organic and hybrid electronics is analyzed and the results obtained are summarized. Recent advances in full and local substrate modification using interface layers are considered in detail. Examples of the most successful applications of interface monolayers as monolayer dielectrics, modifiers of the work function and adhesion promoters are given. The advantages of utilizing interface monolayers at semiconductor/dielectric interfaces and for modifying the semiconductor surface are demonstrated. Specific features of formation of nanostructured surfaces including those used in biosensoric applications are outlined.
关键词： adhesion promoters,work function modifiers,biosensors,organic electronics,interface layers,hybrid electronics,dielectrics,self-assembled monolayers
更新于2025-09-12 10:27:22
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Nonequilibrium site distribution governs charge-transfer electroluminescence at disordered organic heterointerfaces
摘要： The interface between electron-donating (D) and electron-accepting (A) materials in organic photovoltaic (OPV) devices is commonly probed by charge-transfer (CT) electroluminescence (EL) measurements to estimate the CT energy, which critically relates to device open-circuit voltage. It is generally assumed that during CT-EL injected charges recombine at close-to-equilibrium energies in their respective density of states (DOS). Here, we explicitly quantify that CT-EL instead originates from higher-energy DOS site distributions significantly above DOS equilibrium energies. To demonstrate this, we have developed a quantitative and experimentally calibrated model for CT-EL at organic D/A heterointerfaces, which simultaneously accounts for the charge transport physics in an energetically disordered DOS and the Franck–Condon broadening. The 0–0 CT-EL transition lineshape is numerically calculated using measured energetic disorder values as input to 3-dimensional kinetic Monte Carlo simulations. We account for vibrational CT-EL overtones by selectively measuring the dominant vibrational phonon-mode energy governing CT luminescence at the D/A interface using fluorescence line-narrowing spectroscopy. Our model numerically reproduces the measured CT-EL spectra and their bias dependence and reveals the higher-lying manifold of DOS sites responsible for CT-EL. Lowest-energy CT states are situated ～180 to 570 meV below the 0–0 CT-EL transition, enabling photogenerated carrier thermalization to these low-lying DOS sites when the OPV device is operated as a solar cell rather than as a light-emitting diode. Nonequilibrium site distribution rationalizes the experimentally observed weak current-density dependence of CT-EL and poses fundamental questions on reciprocity relations relating light emission to photovoltaic action and regarding minimal attainable photovoltaic energy conversion losses in OPV devices.
关键词： organic electronics,Franck–Condon vibronic progression,energetic disorder,electroluminescence at organic interfaces,3D kinetic Monte Carlo model
更新于2025-09-12 10:27:22
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Improved organic solar cell by incorporating silver nanoparticles embedded polyaniline as buffer layer
摘要： The role of silver nanoparticles (AgNP) in polyaniline (PANI) as a buffer layer for ITO/AgNP-PANI/PANI/Al solar cell was investigated. It is observed that AgNP-PANI buffer layer significantly improves the electrical parameters such as diode-ideality factor, series-resistance, energy-barrier height, and shunt-resistance as a growing function of AgNP concentration. On-the-other hand oppose to the dark current-voltage response, 0.5% concentration of AgNP in buffer layer shows the most optimum photovoltaic response and cause to increase the power conversion efficiency (PCE) nearly 5 times compared to same solar cell without buffer layer. Such improvements in electrical parameters can be interpreted as the reduction in interfacial trap states as well as enhancement in interfacial dipole-moment by AgNP embedded buffer layer for given photovoltaic device. While, the observed optimum photovoltaic behavior at 0.5% AgNP concentration is may be due to the trade-offs between gains and losses for optical absorption enhancement, self-absorption heating and interface recombination losses respectively. It is also observed that the AgNP embedded PANI buffer layer approach is an effective solution to lower the photovoltaic degradation and hence improves the stability of the photovoltaic devices.
关键词： ITO,Silver nanoparticles,Solar cell,Organic semiconductor,Organic electronics,Polyaniline,Buffer layer
更新于2025-09-12 10:27:22
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J-aggregation Enhances the Electroluminescence Performance of Sky-blue TADF Emitter in Non-doped OLEDs
摘要： A pivotal thermally activated delayed fluorescence (TADF) emitter DspiroAc-TRZ was developed, and it exhibits greatly enhanced electroluminescence performance in non-doped organic light-emitting diodes (OLEDs) owing to the concurrent manipulation of aggregation behavior and monomolecular structure. The delicate non-planar packing pattern in DspiroAc-TRZ crystal can not only lead to highly efficient solid-state luminescence, but also form loose intermolecular packing pattern, greatly decreasing the HOMOs or LUMOs overlaps in dimers and shortening triplet exciton diffusion length. In addition, the rigid donor and acceptor moieties in DspiroAc-TRZ can rigidify the molecular backbone, resulting in tiny geometry vibrational relaxation in excited state. Impressively, high photoluminescent quantum yields (PLQYs) of 78.5% and 83.7% were achieved for DspiroAc-TRZ single-crystal and non-doped film. A high external quantum efficiency (EQE) of 25.7% was achieved in non-doped sky-blue TADF-OLED, which is higher than any reported EQE values of non-doped sky-blue TADF-OLEDs so far.
关键词： molecular orientation,non-doped,thermally activated delayed fluorescence,organic electronics,organic light-emitting diodes
更新于2025-09-12 10:27:22
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Manipulating nanoscale structure to control functionality in printed organic photovoltaic, transistor and bioelectronic devices
摘要： Printed electronics is simultaneously one of the most intensely studied emerging research areas today. For the past decade the potential for organic electronic materials to revolutionize this printed electronics space has been widely promoted. Such conviction in the potential of these carbon-based semiconducting materials arises from their ability to be dissolved in solution, and thus the exciting possibility of simply printing a range of multifunctional devices onto flexible substrates at high speeds for very low cost using standard roll-to-roll printing techniques. However, the transition from promising laboratory innovations to large scale prototypes requires precise control of nanoscale material and device structure across large areas during printing fabrication. Maintaining this nanoscale material control during printing presents a significant new challenge that demands the coupling of organic electronic materials and devices with clever nanoscience fabrication approaches that are adapted to the limited thermodynamic levers available. In this review we present an update on the strategies and capabilities that are required in order to manipulate the nanoscale structure of large area printed organic photovoltaic, transistor and bioelectronic devices in order to control their device functionality. This discussion covers a range of efforts to manipulate the electroactive ink materials and their nanostructured assembly into devices, and also device processing strategies to tune the nanoscale material properties and assembly routes through printing fabrication. The ability to control material properties on the nanoscale whilst simultaneously printing functional devices on the square metre scale is prompting a feedback loop between laboratory nanoscience innovations and their feasibility in adapting to large scale printing fabrication. The review finishes by highlighting progress in printed organic electronic devices that provide a pathway towards innovative developments in the targeted nanoscience required for organic photovoltaic, transistor and biofunctional devices.
关键词： organic electronics,biocompatible,printing,large area,nanostructure,semiconductors
更新于2025-09-12 10:27:22
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Solvent influence on the surface morphology of P3HT thin films revealed by photoemission electron microscopy
摘要： Only rigorous understanding of the relationship between the nano-scale morphology of organic thin films and the performance of the devices built from them will ultimately lead to design rules that can guide a structured development on the field of organic electronics. Despite great effort, unraveling the nanoscale structure of the films is still a challenge in itself. Here we demonstrate that photoemission electron microscopy can provide valuable insights into the chain orientation, domains size and grain boundary characteristics of P3HT films spun cast from different solvents at room as well as at elevated temperatures.
关键词： surface morphology,photoemission electron microscopy,organic electronics,solvent influence,P3HT
更新于2025-09-11 14:15:04
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Nucleation mechanism of metal-vapor atoms on photochromic diarylethene surface with a low glass transition temperature
摘要： Metal pattern formation on organic surfaces is essential in organic electronics. Selective metal-vapor deposition using photochromic diarylethene (DAE) is a promising method to prepare ?ne metal patterns by maskless evaporation. Metal-vapor atoms are adsorbed, di?used, and then desorbed from the colorless surface with a low glass transition temperature. We, however, found that metal deposition started at a speci?c time (deposition-threshold time, tth) even on the colorless surface by continuous evaporation. tth was investigated using a quartz crystal microbalance. We elucidated that metal-nucleation sites were generated by chemical reactions between metal atoms and surface DAE molecules. The number of nucleation sites increases during metal evaporation and when the sites are located in the di?usion range of surface metal atoms, metal-atom nucleation for ?lm-formation starts. This is the origin of tth. This result would provide important knowledge for the preparation of electrodes for organic devices based on selective metal-vapor deposition.
关键词： organic electronics,nucleation mechanism,photochromic diarylethene,quartz crystal microbalance,metal-vapor deposition
更新于2025-09-10 09:29:36
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Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes
摘要： A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex donor-acceptor emitters is presented. With a step-by-step procedure, readers will be able to repeat and produce OLED devices based on simple organic emitters. A patterning procedure allowing the creation of personalized indium tin oxide (ITO) shape is shown. This is followed by the evaporation of all layers, encapsulation and characterization of each individual device. The end goal is to present a procedure that will give the opportunity to repeat the information presented in cited publication but also using different compounds and structures in order to prepare efficient OLEDs.
关键词： ambipolar,Donor-Acceptor,Thermally Activated Delayed Fluorescence,exciplex,Organic Electronics,patterning,thermal evaporation,Issue 141,OLED,Engineering
更新于2025-09-09 09:28:46
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Robust Design of Digital Circuits on Foil || Design Case: RFID Tags
摘要： In this chapter, we have presented the designs and technology evolutions that will allow thin-film electronics on plastic foil to fulfill the required specifications for EPC item-level tagging. In particular, we have shown that many of these specifications can be met. A 64-bit organic RFID tag has been elaborated; it is inductively coupled at a base carrier frequency of 13.56 MHz. The complexity of the chip has been increased to a 128-bit transponder chip. Also a basic ALOHA anti-collision protocol and WORM memory have been integrated. EPC-based data rates of 50 kb/s have been reached by downscaling of the technology. These data rates could also be met by using high-performing metal-oxide transistors or by the integration of diode-load or complementary logic. Recently, we demonstrated the possibility for plastic RFID tags to implement a bi-directional communication to realize an anti-collision protocol.
关键词： EPC,WORM memory,thin-film electronics,RFID,bi-directional communication,transponder chip,anti-collision protocol,organic electronics
更新于2025-09-04 15:30:14
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A Highly Stable Organic Radical Cation
摘要： Functionalization of a methylviologen with four methyl ester substituents significantly facilitates the first two reduction steps. The easily generated radical cation shows markedly improved air stability compared to the parent methylviologen, making this derivative of interest in organic electronic applications.
关键词： organic electronics,air stability,methylviologen,radical cation,electron-withdrawing groups
更新于2025-09-04 15:30:14