Two terminal-chlorinated ortho-benzodipyrrole (o-BDP)-based non-fullerene acceptors (NFAs), CFB-Cl and CMB-Cl, were designed and synthesized by incorporating fluorine or methyl substituents on the o-BDP core, respectively. Compared to their terminal-fluorinated counterparts, both NFAs exhibit red-shifted absorption, higher melting points, and stronger intermolecular interactions, attributed to the introduction of chlorinated end groups. Single-crystal X-ray analysis of CFB-Cl revealed a compact three-dimensional kaleidoscopic packing network stabilized by unique F···Cl halogen interactions between the fluorinated o-BDP core and the chlorinated end group, leading to a short π-π stacking distance of 3.38 Å and enhanced charge transport. Consequently, PM6:CFB-Cl devices achieved a PCE of 16.62% with a fill factor (FF) of 75.54%, outperforming PM6:CMB-Cl (PCE = 16.13%). To further improve device performance, a ternary blend strategy was employed by introducing the fluorinated CMB into PM6:CFB-Cl blends to extend the absorption range and improve the morphology. The resulting PM6:CFB-Cl:CMB inverted device exhibited excellent miscibility (χ = 0.02 K), balanced carrier transport (μe/μh = 1.38), suppressed recombination, and a highest PCE of 17.26% with Jsc = 26.02 mA cm-2 and Voc = 0.892 V. This work highlights the importance of halogen engineering in regulating molecular packing and charge dynamics, providing insights into the structure-morphology-performance relationship of o-BDP-based NFAs for next-generation organic photovoltaics.

Photomultiplication organic photodetectors (PM-OPDs) have received substantial interest due to their high sensitivity and tunable spectral response, making them promising candidates for advanced optoelectronic applications. To continuously improve their performance, extensive experimental investigations are imperative. However, computer-aided materials screening could significantly accelerate the development of PM-OPDs. Therefore, we present a comprehensive dataset that encompasses key device performance metrics, the donors and acceptors utilized in active layers, their corresponding codes of simplified molecular input line entry system (SMILES), frontier molecular orbital energy levels, device active areas, applied biases, dark currents, and mass ratios of donors and acceptors. Through data analysis, we identify the essential features of PM-OPDs that are most relevant for training four distinct machine learning (ML) models. The performance of these ML models in predicting external quantum efficiencies (EQE) for PM-OPDs is evaluated using a range of performance metrics. The results indicate that all four ML models exhibit strong correlation coefficients (r > 0.9) in their predictions of the EQE values. Further, PM-OPDs are fabricated from a pair of unseen donor/acceptor materials, and device performance is used to assess the generalization capability of the ML models. This study, to the best of our knowledge, presents the first dataset and ML models specifically focusing on PM-OPDs. We anticipate that the dataset and the ML models will facilitate innovative applications of expert systems in the design and assessment of organic materials for OPDs.

The benzimidazole (BI)-centered acceptor IPF, featuring a perfluorophenyl (C 6 F 5 )-functionalized side chain, leverages fluorine–fluorine interactions to achieve enhanced OPV performance and stability.

This study presents a comprehensive dataset that encompasses the indoor device performance of organic photovoltaic (OPV) materials, their corresponding SMILES codes, and frontier molecular orbital (FMO) energy levels. This dataset comprises a total of 128 subsets and features 64 pairs of donors and acceptors. We demonstrate that traditional models, such as the Shockley–Queisser limit and Scharber’s model, are insufficient for accurately predicting the behavior of indoor OPVs based on the molecular orbitals of these materials. In contrast, we explore the predictive capabilities of four machine learning (ML) models for estimating the power conversion efficiencies (PCEs) of indoor OPVs, utilizing molecular structure information and FMO data from the dataset we compiled. The trained ML models exhibit strong predictive performance with high correlation coefficients (r > 0.8) for indoor PCE values; notably, the support vector regression (SVR) model achieves the highest r of 0.878. The generalization capabilities of the models are also assessed using previously unseen materials, and the results demonstrate high accuracy rates. The SVR algorithm reaches the best average accuracy of 92.1

This article provides an up-to-date review of organic electrolyte-gated transistors. Beginning with an introduction to the fundamental components, mechanisms, configurations, and figures of merit for electrolyte-gated transistors, the article will then transition to an evaluation of the materials used, followed by an overview of past and current applications, ending with the identification of key challenges and opportunities for the organic electrolyte-gated transistor.

The next generations of wearable electronics require high-performance, low-cost, thin, and flexible 2-D electronic components, e.g. capacitors and transistors. The commercial feasibility of these technologies relies on printable, high throughput, highly electronically-conductive, and inexpensive silver electrodes/current collectors to replace gold counterparts. However, silver-based devices are prone to failure due to corrosion forming resistive oxides or dendrites in aqueous environments (as shown in Figure 1a). Polymer electrolytes, possessing high ionic conductivity and enabled double layer capacitance at electrode interface, are highly tunable to minimize the dendritic growth and can be a promising technology for these 2-D devices. In this study, some high-performance aqueous polymer electrolytes that have previously been demonstrated for supercapacitors were compared and modified for better integration into printed interdigitated devices with silver electrodes. The polymer electrolytes were evaluated for their apparent ionic conductivities, capacitance, and corrosion properties using cyclic voltammetry and electrochemical impedance spectroscopy. Polymer electrolytes can effectively inhibit dendritic formation as shown via optical microscope in Fig. 1b. The optimized electrolytes possessed (i) high ionic conductivity (>1 mS cm -1 ) at ambient, (ii) good ability to maintain well-dissociated ions enabling double layer capacitance formation (Fig. 1c), with capacitance >100 μF cm -2 and (iii) good compatibility with silver electrodes. Overall, the optimized polymer electrolytes can be a low-cost, viable alternative in printed electronics requiring high dielectric materials, such as microcapacitors and low-powered field-effect transistors. Figure 1

Two-dimensional (2D) few-layer black phosphorus (BP) with extraordinary electronic and optical properties is an excellent candidate for optoelectronic applications. However, rapid surface oxidation under ambient environment significantly restricts its practicability. Here, we investigate excitonic effect in few-layer BP oxides via first-principle calculation and effective mass approximation. Influence of layer numbers and degree of oxidation on exciton binding energy (EBE) is discussed in detail for the first time. It is found that EBE in BP oxides decreases exponentially with increasing sample thickness and becomes almost oxygen independent over six layers with values similar to that of pristine BP. Instead, oxidation alters excitation probability of excitons in few-layer BP via a direct/indirect bandgap transition.

A new type of printed capacitive humidity sensors with stacked parallel-plate electrodes is presented in this work. The high capacitance and high sensitivity associated with this type of sensors allow the use of low-cost electronic circuits for detection. The use of a polymer sensing material with extremely low hysteresis and a grid top electrode design ensures the sensor’s stable performance and rapid response to humidity changes. Our study shows that the sensor performance can be significantly improved through printing processes and the performance is affected by environment temperature through its influence on water sorption in the sensing material. The temperature effect on the sensors was investigated in detail and the sorption heat of water molecules in the sensing material was estimated. The printed sensor was attached to a printed circuit board (PCB) to become a standalone and functional sensing unit. The PCB board is equipped with light energy harvesting, capacitance measurement, and wireless data transmission, as well as the calibration capability for converting measured capacitance to relative humidity. The obtained unit met the needs for application in high performance building management.

Recent work on printed graphene ink has shown the importance of ethyl cellulose (EC) as a stabilizing polymer in ink formulation and a source of decomposed aromatic species that increase the conductivity of the graphene film. In this work, a reactive molecular dynamic simulation is implemented to study the decomposition of EC in the presence of a pristine graphene and a defective graphene sheet. High temperature annealing simulations revealed that the main reaction pathway of EC polymers is through the decomposition of the cellulose unit backbone into linear chain polymers containing carbon-carbon double bonds. The interactions between EC species and graphene sheets are shown to be maintained through van der Waals forces and the decomposed EC polymers were not observed to undergo chemical reactions with graphene basal-plane defect sites. The results in this paper present the first atomistic study in graphene-EC interactions and lead the way to future computational studies to optimize the electronic properties of printable graphene ink.

Ag2Te colloidal quantum dots (QDs) are an excellent nanomaterial for applications in the second near-infrared window (NIR-II, 1000-1700 nm). However, synthesis with narrow size distribution and high photoluminescence quantum yield (PL QY) is challenging. In this study, we systematically investigate critical synthesis parameters affecting an organic phase process. We show that high Ag/Te feed ratio leads to smaller size and higher PL QY; under 4:1 Ag/Te feed molar ratio, addition of secondary phosphine leads to narrower size distribution and excellent colloidal stability; under 6:1 Ag/Te feed molar ratio, excess 1-dodecanethiol as a strong ligand slows the nucleation and results in fewer nuclei, leading to a broad size distribution and poor optical properties; additional trioctylphosphine as a weak ligand provides better colloidal stability; and another weak ligand tributylphosphine improves QD colloidal stability, focuses size distribution, and enhances PL QY. A noninjection method maintains narrow size distribution in upscaling syntheses. After optimization, relatively large Ag2Te QDs with distinct excitonic absorption peaks (similar to 1050-1450 nm) and PL emission peak 1.3-1.7 mu m (QY up to 6.2%) were obtained. NIR-II photodetection has been demonstrated with a responsivity of similar to 1.5 mA/W at 1400 nm.

A phosphoric acid (H3PO4)-polyvinyl alcohol (PVA) electrolyte was demonstrated as a gate dielectric for electrolyte-gated field-effect transistors (EGFETs). These devices exhibited high performance with sub 1 V operation, a high ON/OFF ratio >10(5) and a low subthreshold swing of 90 mV/decade. The results show the strong viability of proton conducting polymer electrolytes as gate dielectrics which open the door for further development of low-power EGFETs.

Low operating voltages, rapid response, and high-throughput fabrication compatibility are key advantages for the development of electrolyte-gated field effect transistors (EGFETs) for biological sensing.Among the key components in EGFET biosensors, electrolyte materials are relatively less investigated, especially alternatives to water-based liquid electrolytes such as ionic liquids, ion gels, polyelectrolytes, and solid polymer electrolytes.These electrolytes enable portable devices and environmental stability superior to their water-based liquid alternatives.In this review, we offer an up-to-date evaluation of the state of EGFET research and gauge the strengths and limitations of high-performance electrolytes for use in EGFET biosensor applications as well as the potential for computer-aided design of such sensing platforms.The recent progress of EGFET biosensors for some popular analytes are reviewed and the performance of these alternative electrolytes in transistor biosensing is assessed.The challenges and opportunities for electrolytes in EGFETs are discussed for future research directions in this field.

Air-stable solution-processable unipolar n-type organic semiconductors are highly desired in the field of organic thin film transistors as n-type transistors are indispensable components in low-power-consumption complementary integrated circuits. The present work seeks to address this issue and describes the synthesis of two dicyano-substituted bis(2-oxoindolin-3-ylidene)benzodifurandione (BOIBDD) derivatives with engineered alkyl side chains for n-type transistors. Two kinds of side chains are used in this study: 2-hexyldecyl (C16H33) and 3-hexylundecyl (C17H35). Surprisingly, the small structural difference between side chains induced remarkable differences in the physical properties and electronic performance of the BOIBDD derivatives. In addition, cyano substitution into the backbone of BOIBDD derivatives was shown to be effective at lowering the HOMO and LUMO energy levels of BOIBDD derivatives to obtain unipolar n-type materials. Compared with fluorine substitution, cyano substitution was readily realized by a simple and straightforward reaction using cheap CuCN as a cyanation reagent. Both atomic force microscopy (AFM) and X-ray diffraction (XRD) studies have confirmed that the BOIBDD derivative with 3-hexylundecyl side chains tended to form highly crystalline structures in the solid state. More interestingly, thermal annealing of this compound at a temperature as low as 75 degrees C, well below its melting point of 305 degrees C, can still further improve its crystallinity and thus significantly increase its electron mobility by 43 times to 0.1 cm(2) V-1 s(-1) in air. The insight gained from this study will shed some light on the design of new air-stable high-performance n-type organic semiconductors.

Biosensing applications are driving an increase in demand for low-cost photodetectors with sensitivity between 1000 and 1400 nm. Recently, the sensitivity of Ag2Se colloidal quantum dot based devices in this wavelength range has been observed. In this work we make the first demonstration of an Ag2Se photodiode device with sensitivity in this entire range. By employing secondary phosphine to elevate the precursor reactivity, we achieved accurate size control of the Ag2Se nanocrystals with a distinct excitonic absorption peak. These nanocrystals were deposited from solution into a mesoporous TiO2 scaffold, similar to that used in dye-sensitized solar cells, to increase the light absorption and charge separation and reduce the exciton diffusion length. By incorporation of a suitable hole-transporting layer between the active layer and Ag anode, the resulting devices showed a responsivity of 4.17 mA/W at a wavelength of 1200 nm. These results demonstrate that Ag2Se colloidal quantum dots offer a low-toxicity route for low-cost fabrication of near-infrared photodetectors.

An ever expanding landscape of material systems and deposition processes makes accurate and unified modelling of printed electronics systems a daunting challenge. Here we have used an artificial neural network to model inkjet printed organic thin film transistors in an approach which could readily be applied to other material systems and deposition processes. Measured data were used to train the artificial neural network to produce models that could be easily imported into an integrated circuit design environment. Without relying on the underlying physics involved, the artificial neural network was able to model and simulate both DC and AC device characteristics. A monolithically integrated organic complementary logic inverter was used to describe and validate the models. The ability to accurately simulate organic circuits and logic systems, in the absence of robust understanding of the devices, provides the potential for more rapid design and application of printed circuits and systems.

Semiconducting nanocrystals (colloidal quantum dots, QDs) have superior optical properties and solution processibility. Silver selenide quantum dots are important nanomaterials with absorption peak extending from ~880nm to ~1200nm. Compared to the lead-based counterparts, Ag 2 Se QDs are less developed and their application is less explored. This is in part due to the difficult control of their size and size distribution, resulting in broad absorption or even featureless absorption. We employed secondary phosphine to elevate the precursor reactivity and were able to well control the nucleation and growth. After a systematic investigation on a number of synthetic parameters, high quality Ag 2 Se QDs have been synthesized with tunable size and narrow size distribution, exhibiting well-defined absorption peaks. The synthesis is scalable with high yield. The application of Ag 2 Se QDs has been successfully demonstrated in photodetectors with photoresponse in near infrared region (>1000 nm).

Pyrazine-containing moieties were introduced into a semiconducting polymer to improve backbone planarity through a conformational locking effect, leading to good electronic properties and high stability in thin film transistors.

Editor’s note: Thin-film transistors can be manufactured at low cost and on flexible materials using printing technologies. These characteristics make them very well suited to many IoT applications, particularly wearable electronics. However, circuit and system designers require device models for these new devices. This article describes a SPICE-compatible compact model for a range of thin-film transistors. The authors have validated the models on three thin-film transistor technologies. —Dimitrios Serpanos, University of Patras —Marilyn Wolf, Georgia Institute of Technology