Jiuxiang Dai

Nature Reviews Methods Primers, Published online: 09 November 2023; doi:10.1038/s43586-023-00267-2

Crystal orientation engineering is critical for regulating the crystal plane-dependent properties of quasi-1D antimony chalcogenide materials, which in turn affects device efficiency. The regulation of crystal orientation is influenced by various factors such as growth rate, posttreatment, substrate type, interfacial engineering, and the introduction of seeding materials.

Abstract

The emerging antimony chalcogenide (Sb₂(S_xSe_1−x)₃, 0 ≤ x ≤ 1) semiconductors are featured as quasi-1D structures comprising (Sb₄S(e)₆)_n ribbons, this structural characteristic generates facet-dependent properties such as directional charge transfer and trap states. In terms of carrier transport, proper control over the crystal nucleation and growth conditions can promote preferentially oriented growth of favorable crystal planes, thus enabling efficient electron transport along (Sb₄S(e)₆)_n ribbons. Furthermore, an in-depth understanding of the origin and impact of the crystal orientation of Sb₂(S_xSe_1−x)₃ films on the performance of corresponding photovoltaic devices is expected to lead to a breakthrough in power conversion efficiency. In fact, there are many studies on the orientation control of Sb₂(S_xSe_1−x)₃ colloidal nanomaterials. However, the synthesis of Sb₂(S_xSe_1−x)₃ thin films with controlled facets has recently been a focus in optoelectronic device applications. This work summarizes methodologies that are applied in the fabrication of preferentially oriented Sb₂(S_xSe_1−x)₃ films, including treatment strategies developed for crystal orientation engineering in each process. The mechanisms in the orientation control are thoroughly analyzed. An outlook on perspectives for the future development of Sb₂(S_xSe_1−x)₃ solar cells based on recent research and issues on orientation control is finally provided.

Applying the boron-rich closed-loop strategy, a new barium borate, Ba₄B₁₄O₂₅, is designed and synthesized successfully. Benefiting from the high-density π-conjugated [BO₃]³⁻ groups and the fully closed-loop [B₁₄O₂₅]⁸⁻ framework, Ba₄B₁₄O₂₅ exhibits excellent nonlinear optical (NLO) properties, including short UV cutoff edge (<200 nm), large second harmonic generation (SHG) response (3.0 × KDP) and phase-matching capability, being a promising deep ultraviolet (DUV)-transparent NLO candidate material.

Abstract

Discovering new deep ultraviolet (DUV) nonlinear optical (NLO) materials is the current research hotspot. However, how to perfectly integrate several stringent performances into a crystal is a great challenge because of the natural incompatibility among them, particularly wide band gap and large NLO coefficient. To tackle the challenge, a boron-rich closed-loop strategy is supposed, based on which a new barium borate, Ba₄B₁₄O₂₅, is designed and synthesized successfully via the high-temperature solid-state melting method. It features a highly polymeric 3D geometry with the closed-loop anionic framework [B₁₄O₂₅]⁸⁻ constructed by the fundamental building blocks [B₁₄O₃₃]²⁴⁻. The high-density π-conjugated [BO₃]³⁻ groups and the fully closed-loop B–O–B connections make Ba₄B₁₄O₂₅ possess excellent NLO properties, including short UV cutoff edge (<200 nm), large second harmonic generation response (3.0 × KDP) and phase-matching capability, being a promising DUV-transparent NLO candidate material. The work provides a creative design strategy for the exploration of DUV NLO crystals.

Nature Reviews Materials, Published online: 09 November 2023; doi:10.1038/s41578-023-00609-2

This paper proposes low-cost electronic insect traps based on organic flexible large-area electronics for replacing harmful chemical insecticides to protect beneficial insects and natural resources. Electrical impedance characterization of several insect species, capacitive and piezoelectric sensors for detecting insects, high-voltage organic field effect transistors (OFETs) for pest inactivation, and circuits and methods for insect detection and classification are presented.

Abstract

Synthetic insecticides are widely used against plant pest insects to protect the crops. However, many insecticides have poor selectivity and are toxic also to beneficial insects, animals, and humans. In addition, insecticide residues can remain on fruits for many days, jeopardizing food safety. For these reasons, a reusable, low-cost electronic trap that can attract, detect, and identify, but attack only the pest while leaving beneficial insects unharmed could provide a sustainable, nature-friendly replacement. Here, for the first time, research results are presented suggesting the great potential and compatibility of organic electronic devices and technologies with pest management. Electrical characterizations confirm that an insect's body has relatively high dielectric permittivity. Adaptive memcapacitor circuits can track the impedance change for insect detection. Other experiments show that printed polymer piezoelectric transducers on a plastic substrate can collect information about the weight and activity of insects for identification. The breakdown voltage of most insects´ integument is measured to be <200 V. Long channel organic transistors easily work at such high voltages while being safe to touch for humans thanks to their inherent low current. This feasibility study paves the way for the future development of organic electronics for physical pest control and biodiversity protection.

A novel and global relationship between ferroelectric behavior and in-plane tensile strain is discovered in undoped ZrO₂ thin films. Different in-plane tensile strains are expected to stabilize different phases with different electrical properties. This relationship can also be applied to other fluorite-structured ferroelectric thin films, including HfO₂-based ferroelectrics.

Abstract

Since the discovery of ferroelectricity in doped HfO₂ and ZrO₂ thin films over a decade ago, fluorite-structured ferroelectric thin films have attracted much research attention due to their excellent scalability and complementary metal-oxide semiconductor compatibility compared to conventional perovskite ferroelectric materials. Although various factors influencing the formation of the ferroelectric properties are identified, a clear understanding of the causes of the phase formation have been difficult to determine. In this work, ZrO₂ films deposited by atomic layer deposition and chemical solution deposition have resulted in films with completely different structural properties. Regardless of these differences, a general relationship between strain and phase formation is established, leading to a more unified understanding of ferroelectric phase formation in undoped ZrO₂ films, which can be applied to other fluorite-structured films.

Abstract

Reconfigurable devices can be used to achieve multiple logic operation and intelligent optical sensing with low power consumption, which is promising candidates for new generation electronic and optoelectronic integrated circuits. However, the versatility is still limited and need to be extended by the device architectures design. Here, we report an asymmetrically gate two-dimensional (2D) van der Waals heterostructure with hybrid dielectric layer SiO₂/hexagonal boron nitride (h-BN), which enable rich function including reconfigurable logic operation and in-sensor information encryption enabled by both volatile and nonvolatile optoelectrical modulation. When the partial gate is grounded, the non-volatile light assisted electrostatic doping endowed partially reconfigurable doping between n-type and p-type, which allow the switching of logic XOR and not implication (NIMP). When the global gate is grounded, additionally taking the optical signal as another input signal, logic AND and OR is realized by combined regulation of the light and localized gate voltage. Depending on the high on/off current ratio approaching 10⁵ and reliable & switchable logic gate, in-sensor information encryption and decryption is demonstrated by manipulating the logic output. Hence, these results provide strong extension for current reconfigurable electronic and optoelectronic devices.

1H/1T′ MoS₂ heterophase structure is synthesized via a facile chemical vapor deposition method. By precisely controlling the growth atmosphere, the semimetallic 1T′-MoS₂ nanoribbon can be grown on the top of the semiconducting 1H-MoS₂ nanosheet, forming a semiconductor/semimetal heterophase structure. The device fabricated with the 1H/1T′ MoS₂ heterophase structure displays a rectifying behavior, leading to enhanced performance for photodetection.

Abstract

2D heterostructures are emerging as alternatives to conventional semiconductors, such as silicon, germanium, and gallium nitride, for next-generation electronics and optoelectronics. However, the direct growth of 2D heterostructures, especially for those with metastable phases still remains challenging. To obtain 2D transition metal dichalcogenides (TMDs) with designed phases, it is highly desired to develop phase-controlled synthetic strategies. Here, a facile chemical vapor deposition method is reported to prepare vertical 1H/1T′ MoS₂ heterophase structures. By simply changing the growth atmosphere, semimetallic 1T′-MoS₂ can be in situ grown on the top of semiconducting 1H-MoS₂, forming vertical semiconductor/semimetal 1H/1T′ heterophase structures with a sharp interface. The integrated device based on the 1H/1T′ MoS₂ heterophase structure displays a typical rectifying behavior with a current rectifying ratio of ≈10³. Moreover, the 1H/1T′ MoS₂-based photodetector achieves a responsivity of 1.07 A W⁻¹ at 532 nm with an ultralow dark current of less than 10⁻¹¹ A. The aforementioned results indicate that 1H/1T′ MoS₂ heterophase structures can be a promising candidate for future rectifiers and photodetectors. Importantly, the approach may pave the way toward tailoring the phases of TMDs, which can help us utilize phase engineering strategies to promote the performance of electronic devices.

This paper offers a thorough review of atomic layer deposition (ALD) and its applications in supercapacitor electrode development. It scrutinizes the impact of ALD parameters on electrochemical performance, explores its utility in creating 3D nanoarchitectures, and examines the correlation between synthesis techniques and supercapacitor properties. It concludes by outlining potential future research directions to further exploit ALD's unique benefits in the fabrication of advanced supercapacitors.

Abstract

Atomic layer deposition (ALD) has become the most widely used thin-film deposition technique in various fields due to its unique advantages, such as self-terminating growth, precise thickness control, and excellent deposition quality. In the energy storage domain, ALD has shown great potential for supercapacitors (SCs) by enabling the construction and surface engineering of novel electrode materials. This review aims to present a comprehensive outlook on the development, achievements, and design of advanced electrodes involving the application of ALD for realizing high-performance SCs to date, as organized in several sections of this paper. Specifically, this review focuses on understanding the influence of ALD parameters on the electrochemical performance and discusses the ALD of nanostructured electrochemically active electrode materials on various templates for SCs.

It examines the influence of ALD parameters on electrochemical performance and highlights ALD's role in passivating electrodes and creating 3D nanoarchitectures. The relationship between synthesis procedures and SC properties is analyzed to guide future research in preparing materials for various applications. Finally, it is concluded by suggesting the directions and scope of future research and development to further leverage the unique advantages of ALD for fabricating new materials and harness the unexplored opportunities in the fabrication of advanced-generation SCs.

Nature Electronics, Published online: 08 November 2023; doi:10.1038/s41928-023-01063-2

Nature Communications, Published online: 09 November 2023; doi:10.1038/s41467-023-42818-x