A single‐junction polymer solar cell with an efficiency of 10.1% is demonstrated by using deterministic aperiodic nanostructures for broadband light harvesting with optimum charge extraction. The ...performance enhancement is ascribed to the self‐enhanced absorption due to collective effects, including pattern‐induced anti‐reflection and light scattering, as well as surface plasmonic resonance, together with a minimized recombination probability.
Highly power‐efficient white organic light‐emitting diodes (OLEDs) are still challenging to make for applications in high‐quality displays and general lighting due to optical confinement and energy ...loss during electron‐photon conversion. Here, an efficient white OLED structure is shown that combines deterministic aperiodic nanostructures for broadband quasi‐omnidirectional light extraction and a multilayer energy cascade structure for energy‐efficient photon generation. The external quantum efficiency and power efficiency are raised to 54.6% and 123.4 lm W−1 at 1000 cd m−2. An extremely small roll‐off in efficiency at high luminance is also obtained, yielding a striking value of 106.5 lm W−1 at 5000 cd m−2. In addition to a substantial increase in efficiency, this device structure simultaneously offers the superiority of angular color stability over the visible wavelength range compared to conventional OLEDs. It is anticipated that these findings could open up new opportunities to promote white OLEDs for commercial applications.
Highly efficient, white, organic light‐emitting diodes are achieved by combining deterministic aperiodic nanostructures for broadband light extraction with a multilayer energy cascade structure for energy‐efficient photon generation. This results in light‐emitting diodes with a record power efficiency of 123.4 lm W−1 at 1000 cd m−2 with superior color stability and extremely small efficiency roll‐off.
Advanced light manipulation is extremely attractive for applications in organic optoelectronics to enhance light harvesting efficiency. A novel method of fabricating high‐efficiency organic solar ...cells (OSCs) is proposed using biomimetic moth eye nanostructures in a quasi‐periodic gradient shape active layer and an antireflective coating. A 24.3% increase in photocurrent is realized without sacrificing dark electrical properties, yielding a 22.2% enhancement in power conversion efficiency to a record of 7.86% for OSCs with a poly(3‐hexylthiophene‐2,5‐diyl):indene‐C60 bis‐adduct (P3HT:ICBA) active layer. The experimental and theoretical characterizations verify that the substantial improvement of OSCs is mainly ascribed to the self‐enhanced absorption resulting from the broadband polarization‐insensitive light trapping in biomimetic nanostructured active layer, the reduction in reflectance by the antireflective coating, and surface plasmonic effect excited by corrugated metallic electrode. It is noteworthy that the pathway described here is promising for opening up opportunities to realize high‐performance OSCs towards the future photovoltaic applications.
A novel method for light manipulation in organic solar cells by patterning a biomimetic moth‐eye nanostructure into the active layer and adding an antireflective coating is reported. The light harvesting of poly(3‐hexylthiophene‐2,5‐diyl):indene‐C60 bis‐adduct (P3HT:ICBA)‐based solar cells is enhanced to a record efficiency of 7.86% due to the collective excitation of self‐enhanced absorption by broadband polarization‐insensitive light scattering, surface plasmonic resonance, and the antireflective effect.
Organic-based optoelectronic devices, including light-emitting diodes (OLEDs) and solar cells (OSCs) hold great promise as low-cost and large-area electro-optical devices and renewable energy ...sources. However, further improvement in efficiency remains a daunting challenge due to limited light extraction or absorption in conventional device architectures. Here we report a universal method of optical manipulation of light by integrating a dual-side bio-inspired moth's eye nanostructure with broadband anti-reflective and quasi-omnidirectional properties. Light out-coupling efficiency of OLEDs with stacked triple emission units is over 2 times that of a conventional device, resulting in drastic increase in external quantum efficiency and current efficiency to 119.7% and 366 cd A(-1) without introducing spectral distortion and directionality. Similarly, the light in-coupling efficiency of OSCs is increased 20%, yielding an enhanced power conversion efficiency of 9.33%. We anticipate this method would offer a convenient and scalable way for inexpensive and high-efficiency organic optoelectronic designs.
Organic photovoltaics (OPVs) hold great promise for next‐generation photovoltaics in renewable energy because of the potential to realize low‐cost mass production via large‐area roll‐to‐roll printing ...technologies on flexible substrates. To achieve high‐efficiency OPVs, one key issue is to overcome the insufficient photon absorption in organic photoactive layers, since their low carrier mobility limits the film thickness for minimized charge recombination loss. To solve the inherent trade‐off between photon absorption and charge transport in OPVs, the optical manipulation of light with novel micro/nano‐structures has become an increasingly popular strategy to boost the light harvesting efficiency. In this Review, we make an attempt to capture the recent advances in this area. A survey of light trapping schemes implemented to various functional components and interfaces in OPVs is given and discussed from the viewpoint of plasmonic and photonic resonances, addressing the external antireflection coatings, substrate geometry‐induced trapping, the role of electrode design in optical enhancement, as well as optically modifying charge extraction and photoactive layers.
Recent advances in light trapping for organic photovoltaics are reviewed in terms of photon management induced by dielectric or metallic micro/nanostructures. Implementing photonic structures into various functional layers or interfaces is highlighted to lead to the redistribution of optical field in the cells and thus the enhanced light harvesting.
Combinatorial therapy is a promising strategy for combating complex diseases by improving the efficacy and reducing the side effects. To facilitate the identification of drug combinations in ...pharmacology, we proposed a new computational model, termed PDC-SGB, to predict effective drug combinations by integrating biological, chemical and pharmacological information based on a stochastic gradient boosting algorithm. To begin with, a set of 352 golden positive samples were collected from the public drug combination database. Then, a set of 732 dimensional feature vector involving biological, chemical and pharmaceutical information was constructed for each drug combination to describe its properties. To avoid overfitting, the maximum relevance & minimum redundancy (mRMR) method was performed to extract useful ones by removing redundant subsets. Based on the selected features, the three different type of classification algorithms were employed to build the drug combination prediction models. Our results demonstrated that the model based on the stochastic gradient boosting algorithm yield out the best performance. Furthermore, it is indicated that the feature patterns of therapy had powerful ability to discriminate effective drug combinations from non-effective ones. By analyzing various features, it is shown that the enriched features occurred frequently in golden positive samples can help predict novel drug combinations.
•The method for prediction of effective drug combinations was developed using a stochastic gradient boosting algorithm.•Three groups of biological, chemical and pharmacological information were constructed as features.•The maximum relevance & minimum redundancy method was performed for feature selection.
Flexible organic light-emitting diodes (OLEDs) hold great promise for future bendable display and curved lighting applications. One key challenge of high-performance flexible OLEDs is to develop new ...flexible transparent conductive electrodes with superior mechanical, electrical, and optical properties. Herein, an effective nanostructured metal/dielectric composite electrode on a plastic substrate is reported by combining a quasi-random outcoupling structure for broadband and angle-independent light outcoupling of white emission with an ultrathin metal alloy film for optimum optical transparency, electrical conduction, and mechanical flexibility. The microcavity effect and surface plasmonic loss can be remarkably reduced in white flexible OLEDs, resulting in a substantial increase in the external quantum efficiency and power efficiency to 47.2% and 112.4 lm W–1.
Metal halide perovskites, a class of crystalline semiconductors with unique optical and electronic properties, are emerging as potential solutions for low‐cost photovoltaics and photonic sources in ...fields of solar cells, sensors, light‐emitting diodes and lasers. Regardless of significant progress on device efficiency with the control over perovskite structures and film morphologies, unveiling the interface energetics and band alignment of these perovskite systems is indispensable for the performance optimization in the optoelectronic applications by grasping the photon harvest and charge transport processes. Herein we review the recent advances in the energetics of metal halide perovskite interfaces. The electronic properties of perovskite materials are addressed in terms of halide substitution, thermal annealing and substrate effects as well as trap states. The energy level alignments of interfaces between perovskite films and charge transport layers are then discussed, which is correlated to the photovoltaic properties in perovskite solar cells.
Recent advances in energetics in metal halide perovskite interfaces are reviewed with a combined discussion of electronic structures of metal halide perovskites and energy level alignment at perovskite/organic heterointerfaces through photoemission spectroscopy techniques. The energetics at the perovskite interfaces with various carrier transport materials is highlighted, suggesting the impact on photocurrent generation process in perovskite solar cells.
The basic helix-loop-helix (bHLH) transcription factors are widely distributed across eukaryotic kingdoms and participate in various physiological processes. To date, the bHLH family has been ...identified and functionally analyzed in many plants. However, systematic identification of bHLH transcription factors has yet to be reported in orchids. Here, 94 bHLH transcription factors were identified from the
genome and divided into 18 subfamilies. Most
contain numerous
elements associated with abiotic stress responses and phytohormone responses. A total of 19 pairs of duplicated genes were found in the
, of which 13 pairs were segmentally duplicated genes and six pairs were tandemly duplicated genes. Expression pattern analysis based on transcriptome data revealed that 84
were differentially expressed in four different color sepals, especially
and
of the S7 subfamily. The expression profiles of
and
in sepals, which are considered potential genes regulating anthocyanin biosynthesis, were confirmed through the qRT-PCR technique. Furthermore, subcellular localization results showed that CebHLH13 and CebHLH75 were located in the nucleus. This research lays a foundation for further exploration of the mechanism of
in flower color formation.
Directly linearly polarized light emission from organic light‐emitting diodes (OLEDs), as an important functional expansion, is an intriguing and attractive research topic due to its increasing ...importance in various applications. Until now, however, the limited efficiency and inadequate polarization ratio constitute two major hurdles for real application. In this work, high‐efficiency linearly polarized white OLEDs with an ultrahigh polarization ratio are achieved by using integrated dielectric/metal nanograting and nanorelief speckle image holography metasurfaces. In the devices, the integrated grating behave as a polarizer to select the transverse magnetic wave (TM) component and simultaneously reflect the transverse electric wave (TE) counterpart over the whole emission spectrum, while the metasurfaces gather the otherwise waste TE‐polarized light reflected by the grating and transform it into reusable TM‐polarized light. This synergistic energy‐light recycling system leads to dramatically boosted device efficiency and polarization ratio, i.e., a power efficiency 21.4 lm W−1 (@ 1000 cd m−2), and an extinction ratio of 17.8 dB (@ V = 5 V) for the polarized white OLEDs. The presented paradigm for simultaneous polarization controlling and efficiency boosting in white OLEDs is expected to advance the OLED techniques in device reconfigurability for future multifunctional applications.
A new approach to tailor polarization conversion and light‐energy recycling for highly linearly polarized white organic light‐emitting diodes with integrated nanograting and nanorelief speckle image holography metasurfaces is conceived. This synergistic energy‐light recycling system plays a novel and dual role of dramatically boosting the device efficiency and polarization ratio.
PDF
