Control over the morphology and crystallinity of metal halide perovskite materials is of key importance to enable high‐performance optoelectronics. Here, a simple yet effective template‐free ...self‐assembly synthesis of perovskite granular wires with ultrahigh photodetectivity (3.17 × 1015 Jones) is reported. The 1D self‐assembly of perovskite grains is driven by differences in the surface interaction energies of the granular facets. The superb photodetecting performance originates from extremely low dark current engendered by energetic barriers featuring unique band‐edge modulation along the long axis of wire. Flexible photodetector arrays, fabricated by selectively placing perovskite granular wires onto pre‐patterned electrode arrays on a transparent polymer substrate, show independently addressable photonic signal mapping with remarkably high detectivity, photoconductive gain, and responsivity. The “self‐assembled nanograin engineering” strategy developed in this study provides a viable method for the development of high‐performance perovskite photodetectors and can be extended to other integrated optoelectronic systems.
Perovskite granular wires synthesized by a simple yet effective template‐free self‐assembly exhibit superior photodetecting performance with unprecedentedly high photodetectivity, originating from the low dark current due to band‐edge modulation along the long axis of the granular wires. The “self‐assembled nanograin engineering” strategy provides a viable method for the development of high‐performance perovskite photodetectors and can be extended to other integrated optoelectronic systems.
Abstract
Chiral metamaterials have received significant attention due to their strong chiroptical interactions with electromagnetic waves of incident light. However, the fabrication of large-area, ...hierarchically manufactured chiral plasmonic structures with high dissymmetry factors (
g-
factors) over a wide spectral range remains the key barrier to practical applications. Here we report a facile yet efficient method to fabricate hierarchical chiral nanostructures over a large area (>11.7 × 11.7 cm
2
) and with high
g
-factors (up to 0.07 in the visible region) by imparting extrinsic chirality to nanostructured polymer substrates through the simple exertion of mechanical force. We also demonstrate the application of our approach in the polarized emission of quantum dots and information encryption, including chiral quick response codes and anti-counterfeiting. This study thus paves the way for the rational design and fabrication of large-area chiral nanostructures and for their application in quantum communications and security-enhanced optical communications.
The recent development of neuromorphic devices with low power consumption and rapid response has been driven primarily by the growing demand for brain‐inspired computing in human‐like machines and ...human‐machine interfaces. Remarkable progress has been made in developing neuromorphic bioelectronics that combine neuromorphic devices with electronic sensors. In this review, we provide an overview of semiconducting polymer‐based neuromorphic devices and their applications in neuromorphic bioelectronics. We focus on recent advances in semiconducting polymer‐based three‐terminal artificial synapses that mimic neural communication behaviors. Various types of semiconducting polymers and synaptic platforms have been investigated, allowing significant improvement in their performance and expansion of their functionality. Proper selection of materials and device structures can help artificial sensory synapses to react to various external stimuli and to further modulate electrical signals. Advances in semiconducting polymer‐based neuromorphic bioelectronics will accelerate the commercialization of human–machine interfacial systems, including intelligent prosthetics and implantable diagnostic devices.
Soft electronic materials are key elements for realizing wearable, attachable, and stick-on electronics. The development of deformable and stretchable electrodes is a key research area as they are ...one of the most important components for soft electronic devices. Recently, significant progress in the development of deformable and stretchable electrodes has been achieved with organic materials offering electrical tunability, simple mechanical implementation, and desirable chemical and optical properties. In this review, we present recent progress in the design of stretchable electronics based on deformable conducting materials, including their fabrication and conductivity properties and the methods that are employed to enhance performance. In addition, we review the development status of organic- and carbon- based conductive materials and their hybrid composites being used for electronic applications, including carbon nanotubes, graphene, metal composites, conductive polymers, hybrid composites, and ion gel composites. The structural aspects, such as wavy or mesh configurations, of stretchable electrodes and other high-performance conducting materials are investigated intensively. Many stretchable electrodes show great potential for use in future electronics such as electronic skin (e-skin) and stretchable displays, which require reversible deformation and a high degree of operational stability.
The field of organic mixed ionic‐electronic conductors (OMIECs) has gained significant attention due to their ability to transport both electrons and ions, making them promising candidates for ...various applications. Initially focused on inorganic materials, the exploration of mixed conduction has expanded to organic materials, especially polymers, owing to their advantages such as solution processability, flexibility, and property tunability. OMIECs, particularly in the form of polymers, possess both electronic and ionic transport functionalities. This review provides an overview of OMIECs in various aspects covering mechanisms of charge transport including electronic transport, ionic transport, and ionic–electronic coupling, as well as conducting/semiconducting conjugated polymers and their applications in organic bioelectronics, including (multi)sensors, neuromorphic devices, and electrochromic devices. OMIECs show promise in organic bioelectronics due to their compatibility with biological systems and the ability to modulate electronic conduction and ionic transport, resembling the principles of biological systems. Organic electrochemical transistors (OECTs) based on OMIECs offer significant potential for bioelectronic applications, responding to external stimuli through modulation of ionic transport. An in‐depth review of recent research achievements in organic bioelectronic applications using OMIECs, categorized based on physical and chemical stimuli as well as neuromorphic devices and circuit applications, is presented.
The recent development of organic bioelectronics based on organic mixed ionic–electronic semiconductors/conductors (OMIECs) is reviewed. Multifunctional properties of OMIECs including sensing, energy harvesting/storage, information transfer, and actuation enable them to function as the active component of multiple devices such as transistors, sensors, electrochemical transistors, electro/photochromic devices, and artificial synapses.
In article number 2002357, Sang Kyu Kwak, Joon Hak Oh, and co‐workers synthesize perovskite granular wires by a simple yet effective template‐free self‐assembly. Superb photodetection performance ...with unprecedentedly high photodetectivity is exhibited, which originates from the low dark current due to the band‐edge modulation along the long axis of the granular wires. This “self‐assembled nanograin engineering” strategy provides a viable method for the development of high‐performance perovskite photodetectors and can be extended to other integrated optoelectronic systems.
Abstract
Hybrid materials in optoelectronic devices can provide synergistic effects that complementarily enhance the properties of each component. Here, flexible high-performance graphene hybrid ...photodetectors (PDs) are developed by introducing gold nanostars (GNSs) and perovskites for strong light trapping with hot electron transfer and efficient light harvesting characteristics, respectively. While pristine graphene PDs do not exhibit discernible photodetection properties due to the very low photon absorption and ultrafast charge carrier recombination, graphene PDs functionalized with GNSs and a densely covered perovskite layer exhibit outstanding photoresponsive properties with a photoresponsivity (
R
) of 5.90 × 10
4
A W
−1
and a specific detectivity of 1.31 × 10
13
Jones, the highest values among those reported for perovskite-functionalized graphene PDs thus far. Moreover, we fabricated a flexible 10 × 10 PD array that shows well-resolved spatiotemporal mapping of light signals with excellent operational and mechanical stabilities at a bending radius down to 3 mm and in repeated bending tests for over 1000 cycles. Comprehensive analyses using finite-difference time-domain (FDTD) theoretical calculations, scanning near-field optical microscopy, and photoluminescence mapping reveal the effective light trapping effect of GNSs and the charge carrier transfer between the perovskite and graphene. This work provides a new design platform for flexible and high-performance photodetection systems.
Abstract
Transition metal dichalcogenide MoS
2
is a two-dimensional material, attracting much attention for next-generation applications thanks to rich functionalities stemming from its crystal ...structure. Many experimental and theoretical works have focused on the spin-orbit interaction which couples the valley and spin degrees of freedom so that the spin-states can be electrically controllable. However, the spin-states of charge carriers and atomic vacancies in devices have not been yet elucidated directly from a microscopic viewpoint. Here, we report the spin-states in thin-film transistors using operando electron spin resonance spectroscopy. We have observed clearly different electron spin resonance signals of the conduction electrons and atomic vacancies, and distinguished the corresponding spin-states from the signals and theoretical calculations, evaluating the gate-voltage dependence and the spin-susceptibility and
g
-factor temperature dependence. This analysis gives deep insight into the MoS
2
magnetism and clearly indicates different spin-scattering mechanisms compared to graphene, which will be useful for improvements of the device characteristics and new applications.
Plasmonic nanostructures can enhance the performance of photodetectors (PDs) owing to their amplification effect in light absorption, leading to overcoming the inherent properties of the photoactive ...layer. Herein, hierarchical plasmonic nanopatterns have been prepared and used for high‐performance flexible perovskite PDs. The developed hierarchical nanostructures, featuring nanoposts on cross‐nanograting patterns, exhibit a notably enhanced light trapping effect compared to hierarchical nanostructures based on a unidirectional simple nanograting structure. Moreover, hierarchical pattern‐based perovskite PDs show a photoresponsivity of 580 mA W−1 and a specific detectivity of 3.2 × 1012 Jones, which are 420% and 990% higher than those of perovskite PDs without plasmonic nanostructures, respectively. Furthermore, a flexible 10 × 10 PD array has been developed, which enables the accurate mapping of light signals with exceptional operational and mechanical stabilities, under a bending radius as small as 8 mm and after undergoing more than 1000 bending cycles. Comprehensive analyses using finite‐difference time‐domain calculations and photoluminescence mapping reveal the effective light trapping effect of hierarchical plasmonic patterns in the perovskite layers. This work provides an efficient approach to achieve high‐performance perovskite optoelectronic devices.
Novel hierarchical plasmonic nanostructures are designed to enable versatile plasmoinc light amplification by combining cross‐nanograting and nanopost structures. By utilizing the hierarchical plasmonic structures, flexible perovskite photodetectors (PDs) with significantly improved performance and high mechanical stability can be achieved owing to their efficient light amplification effects, which extends the range of their practical applications.
Hybrid photovoltaics (HPVs) incorporating both organic and inorganic semiconducting materials have attracted much attention as next-generation photovoltaics because of their advantage of combining ...both materials. The hybridization of ZnO nanowires (NWs) and organic semiconductors is expected to be a suitable approach to overcome the limited exciton diffusion length and low electron mobility associated with current organic photovoltaics. The use of ZnO NWs allows researchers to tune nanoscale dimensions more precisely and to achieve rod-to-rod spacing below 10 nm. However, the perfect incorporation of organic semiconductors into densely packed ZnO NW arrays has yet to be achieved. In this study, we report the fabrication of ZnO NW arrays and various organic heterojunction-based HPVs using the feasible and effective vacuum-assisted double coating (VADC) method, achieving full coverage of the organic semiconductors on the compact ZnO NW arrays. The newly proposed VADC method ensures perfect infiltration and full coverage of the organic semiconductors on the densely packed NW arrays. Compared with the conventional single spin-coating process, the use of the VADC method led to 11 and 14% increases in the power conversion efficiency of P3HT:PCBM- and PBDTTT-C-T:PC71BM-based HPVs, respectively. Our studies provide a feasible method for the fabrication of efficient HPVs.
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