We designed and synthesized a series of fused-ring electron acceptors (FREAs) based on naphthalene-fused octacyclic cores end-capped by 3-(1,1-dicyanomethylene)-5,6-difluoro-1- indanone (NOICs) using ...a bottom-up approach. The NOIC series shares the same end groups and side chains, as well as similar fused-ring cores. The butterfly effects, arising from different methoxy positions in the starting materials, impact the design of the final FREAs, as well as their molecular packing, optical and electronic properties, charge transport, film morphology, and performance of organic solar cells. The binary-blend devices based on this NOIC series show power conversion efficiencies varying from 7.15% to 14.1%, due to the different intrinsic properties of the NOIC series, morphologies of blend films, and voltage losses of devices.
Perovskite solar cells (PSCs) based on organic–inorganic hybrid materials are a rising technology offering an alternative to silicon‐based solar cells. Electron‐transport materials (ETMs) are ...important for PSCs and have received much attention. Here, first, the development of the structure of PSCs, from which the ETM requirements would be derived, is briefly discussed. Second, the progress of ETMs in mesoscopic PSCs, as well as regular (n–i–p) and inverted (p–i–n) planar PSCs is surveyed and analyzed, in terms of the material requirements, inorganic ETMs, organic ETMs, and interfacial materials. Third, the advancement of PSCs without ETMs is discussed. Finally, a summary and outlook on the current challenges and future development of ETMs in PSCs is given.
The electron transport materials (ETMs) in mesoscopic and planar perovskite solar cells (PSCs) with regular and inverted structures are reviewed; the comparison between organic and inorganic ETMs is discussed; and the development perspective of ETM‐free PSCs is forecast.
Organic electron‐transporting materials are essential for the fabrication of organic p‐n junctions, photovoltaic cells, n‐channel field‐effect transistors, and complementary logic circuits. Rylene ...diimides are a robust, versatile class of polycyclic aromatic electron‐transport materials with excellent thermal and oxidative stability, high electron affinities, and, in many cases, high electron mobilities; they are, therefore, promising candidates for a variety of organic electronics applications. In this review, recent developments in the area of high‐electron‐mobility diimides based on rylenes and related aromatic cores, particularly perylene‐ and naphthalene‐diimide‐based small molecules and polymers, for application in high‐performance organic field‐effect transistors and photovoltaic cells are summarized and analyzed.
Electronic devices based on organic materials offer the potential of low‐cost processing on flexible substrates when compared to traditional inorganic semiconductors. Rylene diimides have recently shown promise as potential alternatives to the fullerenes as acceptors in photovoltaic devices, exhibiting power conversion efficiencies that are amongst the highest achieved for all‐polymer fullerene‐free systems. This article reviews their development for both transistor and solar cell applications.
The bulk morphology of the active layer of organic solar cells (OSCs) is known to be crucial to the device performance. The thin film device structure breaks the symmetry into the in-plane direction ...and out-of-plane direction with respect to the substrate, leading to an intrinsic anisotropy in the bulk morphology. However, the characterization of out-of-plane nanomorphology within the active layer remains a grand challenge. Here, we utilized an X-ray scattering technique, Grazing-incident Transmission Small-angle X-ray Scattering (GTSAXS), to uncover this new morphology dimension. This technique was implemented on the model systems based on fullerene derivative (P3HT:PC
BM) and non-fullerene systems (PBDBT:ITIC, PM6:Y6), which demonstrated the successful extraction of the quantitative out-of-plane acceptor domain size of OSC systems. The detected in-plane and out-of-plane domain sizes show strong correlations with the device performance, particularly in terms of exciton dissociation and charge transfer. With the help of GTSAXS, one could obtain a more fundamental perception about the three-dimensional nanomorphology and new angles for morphology control strategies towards highly efficient photovoltaic devices.
A novel small molecule based on indacenodithiophene and 1,1-dicyanomethylene-3-indanone was synthesized and used as an electron acceptor in solution processed organic solar cells, which exhibited a ...power conversion efficiency as high as 3.93%.
Diluting concentrated solution (DCS) is a new, simple, general and effective approach to improve power conversion efficiencies (PCEs) of polymer solar cells (PSCs). PCEs of binary blend PSCs, ternary ...blend PSCs and all-polymer solar cells fabricated using this method are enhanced by a factor as high as 37% relative to those using the general process.
Organic photodetectors (OPDs), which usually work as photodiodes, photoconductors, or phototransistors, have emerged as candidates for next‐generation light sensing. However, low response speed ...caused by low carrier mobility and resistance‐capacitance (RC) time constant, severely hinders the commercialization of OPDs. Herein, the authors demonstrate a state‐of‐the‐art OPD with a record response speed of 146.8 ns by employing tandem structure to simultaneously reduce both the carrier transit time and RC time constant of the device, which is faster than that of previously reported OPDs as far as they know. Moreover, benefitting from the multi‐level barrier enhancement and voltage division engendered by tandem structure, an ultralow noise current of 7.82 × 10−14 A Hz−1/2 is obtained, as well as a wide detection range in 300–1000 nm. In addition, the tandem OPDs are successfully integrated into the optical communication system as signal receivers, demonstrating the precise digital signal communication from visible to near‐infrared light. It is believed that tandem OPDs have promising application potential in the wireless transmission system.
A solution‐processed organic tandem photodetector that simultaneously integrates fast response, low noise, and broadband has been demonstrated, indicating a 146.8 ns response speed. Encouragingly, it is successfully applied to the optical communication system, realizing the transmission of digital signals and visualization of the near‐infrared light.
Accurate diagnosis and prognosis are essential in lung cancer treatment selection and planning. With the rapid advance of medical imaging technology, whole slide imaging (WSI) in pathology is ...becoming a routine clinical procedure. An interplay of needs and challenges exists for computer-aided diagnosis based on accurate and efficient analysis of pathology images. Recently, artificial intelligence, especially deep learning, has shown great potential in pathology image analysis tasks such as tumor region identification, prognosis prediction, tumor microenvironment characterization, and metastasis detection.
In this review, we aim to provide an overview of current and potential applications for AI methods in pathology image analysis, with an emphasis on lung cancer.
We outlined the current challenges and opportunities in lung cancer pathology image analysis, discussed the recent deep learning developments that could potentially impact digital pathology in lung cancer, and summarized the existing applications of deep learning algorithms in lung cancer diagnosis and prognosis.
With the advance of technology, digital pathology could have great potential impacts in lung cancer patient care. We point out some promising future directions for lung cancer pathology image analysis, including multi-task learning, transfer learning, and model interpretation.
Solar cells, a renewable, clean energy technology that efficiently converts sunlight into electricity, are a promising long-term solution for energy and environmental problems caused by a mass of ...production and the use of fossil fuels. Solution-processed organic solar cells (OSCs) have attracted much attention in the past few years because of several advantages, including easy fabrication, low cost, lightweight, and flexibility. Now, OSCs exhibit power conversion efficiencies (PCEs) of over 10%. In the early stage of OSCs, vapor-deposited organic dye materials were first used in bilayer heterojunction devices in the 1980s, and then, solution-processed polymers were introduced in bulk heterojunction (BHJ) devices. Relative to polymers, vapor-deposited small molecules offer potential advantages, such as a defined molecular structure, definite molecular weight, easy purification, mass-scale production, and good batch-to-batch reproducibility. However, the limited solubility and high crystallinity of vapor-deposited small molecules are unfavorable for use in solution-processed BHJ OSCs. Conversely, polymers have good solution-processing and film-forming properties and are easily processed into flexible devices, whereas their polydispersity of molecular weights and difficulty in purification results in batch to batch variation, which may hamper performance reproducibility and commercialization. Oligomer molecules (OMs) are monodisperse big molecules with intermediate molecular weights (generally in the thousands), and their sizes are between those of small molecules (generally with molecular weights <1000) and polymers (generally with molecular weights >10000). OMs not only overcome shortcomings of both vapor-deposited small molecules and solution-processed polymers, but also combine their advantages, such as defined molecular structure, definite molecular weight, easy purification, mass-scale production, good batch-to-batch reproducibility, good solution processability, and film-forming properties. Therefore, OMs are a good choice for solution-processed reproducible OSCs toward scalable commercialized applications. Considerable efforts have been dedicated to developing new OM electron donors and electron acceptors for OSCs. So far, the highest PCEs of solution-processed OSCs based on OM donors and acceptors are 9–10% and 6–7%, respectively. OM materials have become promising alternatives to polymer and/or fullerene materials for efficient and stable OSCs. In this Account, we present a brief survey of the recent developments in solution-processable OM electron donors and acceptors and their application in OSCs. Rational design of OMs with star- and linear-shaped structures based on triphenylamine, benzodithiophene, and indacenodithiophene units and their impacts on device performance are discussed. Structure–property relationships are also proposed. Furthermore, the remaining challenges and the key research directions in the near future are also addressed. In the next years, an interdisciplinary approach involving novel OM materials, especially electron acceptor materials, accurate morphology optimization, and advanced device technologies will probably bring high-efficiency and stable OSCs to final commercialization.
Accurate estimation of individual ancestry is important in genetic association studies, especially when a large number of samples are collected from multiple sources. However, existing approaches ...developed for genome-wide SNP data do not work well with modest amounts of genetic data, such as in targeted sequencing or exome chip genotyping experiments. We propose a statistical framework to estimate individual ancestry in a principal component ancestry map generated by a reference set of individuals. This framework extends and improves upon our previous method for estimating ancestry using low-coverage sequence reads (LASER 1.0) to analyze either genotyping or sequencing data. In particular, we introduce a projection Procrustes analysis approach that uses high-dimensional principal components to estimate ancestry in a low-dimensional reference space. Using extensive simulations and empirical data examples, we show that our new method (LASER 2.0), combined with genotype imputation on the reference individuals, can substantially outperform LASER 1.0 in estimating fine-scale genetic ancestry. Specifically, LASER 2.0 can accurately estimate fine-scale ancestry within Europe using either exome chip genotypes or targeted sequencing data with off-target coverage as low as 0.05×. Under the framework of LASER 2.0, we can estimate individual ancestry in a shared reference space for samples assayed at different loci or by different techniques. Therefore, our ancestry estimation method will accelerate discovery in disease association studies not only by helping model ancestry within individual studies but also by facilitating combined analysis of genetic data from multiple sources.
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