Liquid-solid spinodal decomposition mediated synthesis of Sb₂Se₃ nanowires and their photoelectric behavior

Recent Advances in Antimony Selenide Photodetectors

Photodetectors (PDs) rapidly capture optical signals and convert them into electrical signals, making them indispensable in a variety of applications including imaging, optical communication, remote sensing, and biological detection. Recently, antimony selenide (Sb2Se3) has achieved remarkable progress due to its earth-abundant, low toxicity, low price, suitable bandgap width, high absorption coefficient, and unique structural characteristics. Sb2Se3 has been extensively studied in solar cells, but there's a lack of timely updates in the field of PDs. A literature review based on Sb2Se3 PDs is urgently warranted. This review aims to provide a concise understanding of the latest progress in Sb2Se3 PDs, with a focus on the basic characteristics and the performance optimization for Sb2Se3 photoconductive-type and photodiode-type detectors, including nanostructure regulation, process optimization, and stability improvement of flexible devices. Furthermore, the application progresses of Sb2Se3 PDs in heart rate monitoring, and monolithic-integrated matrix images are introduced. Finally, this review presents various strategies with potential and feasibility to address challenges for the rapid development and commercial application of Sb2Se3 PDs.

Smart Bifunctional Sb2 Se3 Nanorods for Integrated Water Purification: Insoluble Liquid Separation and Photoelectrochemical Degradation

Antimony selenide (Sb₂ Se₃ ) nanostructures enable bifunctional water purification by a single membrane through i) physical separation of water-insoluble oil and ii) photoelectrocatalytic degradation of water-soluble organic compounds. Sb₂ Se₃ nanorods with exposed surfaces of {h 0 0} and {h 0 l} planes exhibit superhydrophobicity (water contact angle of ≈159°) owing to extremely low surface energy of those dangling-bond-free van der Waals planes. Based on crystallographic understanding, superhydrophobic Sb₂ Se₃ nanorods were produced on a mesh-type substrate for utilization as a membrane for physical water/oil separation. Sb₂ Se₃ exhibited an optimal photocathodic response with p-type electrical conductivity under visible light along the longitudinal crystal direction. This indicated that the nanorods could be used as photoelectrocatalytic material for chemical water purification. A smart membrane with Sb₂ Se₃ nanostructures was proposed as a candidate for integrated water purification that can simultaneously accomplish water/oil separation and photoelectrocatalytic degradation of organic compounds in wastewater. Linear sweep voltammetry measurements of the Sb₂ Se₃ -membrane showed cathodic photocurrent generation (up to approximately 10 mA cm^-2 at 0 V vs. reversible hydrogen electrode), which was enough to reduce O₂ to an oxygen radical (O₂ ^.- ) for degradation of methyl orange. Consequently, solar-driven integrated water purification was demonstrated for the first time by using a single material with a dual function of superhydrophobicity and photoactivity.

A highly [001]-textured Sb2Se3 photocathode for efficient photoelectrochemical water reduction

Anisotropic Sb₂Se₃ is an emerging earth-abundant photocathode for photoelectrochemical water splitting. However, controlling the growth of the Sb₂Se₃ film with optimal [001] crystallographic orientation is still the most challenging issue. Here, we successfully synthesized [001]-oriented Sb₂Se₃via a reliable and facile method. The [001]-oriented Sb₂Se₃ film could provide an excellent carrier-migration efficiency. Consequently, we achieved a record-high photocurrent density of -20.2 mA cm^-2 at 0 V_RHE and a very high half-cell solar-to-hydrogen efficiency of 1.36% under 1-sun simulated solar illumination in a TiO₂/[001]-Sb₂Se₃ photocathode. This work provides an effective strategy and important guidelines for rationally designing optoelectronic devices based on the [001]-oriented Sb₂Se₃ film.

Computational Approaches to Photoelectrode Design through Molecular Functionalization for Enhanced Photoelectrochemical Water Splitting

Photoelectrochemical water splitting is a promising carbon-free approach to produce hydrogen from water. A photoelectrochemical cell consists of a semiconductor photoelectrode in contact with an aqueous electrolyte. Its performance is sensitive to properties of the photoelectrode/electrolyte interface, which may be tuned through functionalization of the photoelectrode surface with organic molecules. This can lead to improvements in the photoelectrode's properties. This Minireview summarizes key computational investigations on using molecular functionalization to modify photoelectrode stability, barrier height, and catalytic activity. It is discussed how first-principles density functional theory, first-principles molecular dynamics, and device modeling simulations can provide predictive insights and complement experimental investigations of functionalized photoelectrodes. Challenges and future directions in the computational modeling of functionalized photoelectrode/electrolyte interfaces within the context of experimental studies are also highlighted.

Recent Advances in Earth-Abundant Photocathodes for Photoelectrochemical Water Splitting

The conversion of solar energy into hydrogen through photoelectrochemical (PEC) water splitting is an attractive way to store renewable energy. Despite the intriguing concept of solar hydrogen production, efficient PEC devices based on earth-abundant semiconductors should be realized to compete economically with conventional steam reforming processes. Herein, recent milestones in photocathode development for PEC water splitting, particularly in earth-abundant semiconductors, in terms of new techniques for enhancing performance, as well as theoretical aspects, are highlighted. In addition, recent research into newly emerging low-cost p-type semiconductors in the PEC field, such as Cu₂ BaSn(S,Se)₄ and Sb₂ Se₃ , are scrutinized and the advantages and disadvantages of each material assessed.

Chemical Vapor Deposition Growth of High Crystallinity Sb2 Se3 Nanowire with Strong Anisotropy for Near-Infrared Photodetectors

Low-dimensional semiconductors have attracted considerable attention due to their unique structures and remarkable properties, which makes them promising materials for a wide range of applications related to electronics and optoelectronics. Herein, the preparation of 1D Sb₂ Se₃ nanowires (NWs) with high crystal quality via chemical vapor deposition growth is reported. The obtained Sb₂ Se₃ NWs have triangular prism morphology with aspect ratio range from 2 to 200, and three primary lattice orientations can be achieved on the sixfold symmetry mica substrate. Angle-resolved polarized Raman spectroscopy measurement reveals strong anisotropic properties of the Sb₂ Se₃ NWs, which is also developed to identify its crystal orientation. Furthermore, photodetectors based on Sb₂ Se₃ NW exhibit a wide spectral photoresponse range from visible to NIR (400-900 nm). Owing to the high crystallinity of Sb₂ Se₃ NW, the photodetector acquires a photocurrent on/off ratio of about 405, a responsivity of 5100 mA W^-1 , and fast rise and fall times of about 32 and 5 ms, respectively. Additionally, owing to the anisotropic structure of Sb₂ Se₃ NW, the device exhibits polarization-dependent photoresponse. The high crystallinity and superior anisotropy of Sb₂ Se₃ NW, combined with controllable preparation endows it with great potential for constructing multifunctional optoelectronic devices.

Scalable Low-Band-Gap Sb2Se3 Thin-Film Photocathodes for Efficient Visible-Near-Infrared Solar Hydrogen Evolution

A highly efficient low-band-gap (1.2-0.8 eV) photoelectrode is critical for accomplishing efficient conversion of visible-near-infrared sunlight into storable hydrogen. Herein, we report an Sb₂Se₃ polycrystalline thin-film photocathode having a low band gap (1.2-1.1 eV) for efficient hydrogen evolution for wide solar-spectrum utilization. The photocathode was fabricated by a facile thermal evaporation of a single Sb₂Se₃ powder source onto the Mo-coated soda-lime glass substrate, followed by annealing under Se vapor and surface modification with an antiphotocorrosive CdS/TiO₂ bilayer and Pt catalyst. The fabricated Sb₂Se₃(Se-annealed)/CdS/TiO₂/Pt photocathode achieves a photocurrent density of ca. -8.6 mA cm^-2 at 0 V_RHE, an onset potential of ca. 0.43 V_RHE, a stable photocurrent for over 10 h, and a significant photoresponse up to the near-infrared region (ca. 1040 nm) in near-neutral pH buffered solution (pH 6.5) under AM 1.5G simulated sunlight. The obtained photoelectrochemical performance is attributed to the reliable synthesis of a micrometer-sized Sb₂Se₃ (Se-annealed) thin film as photoabsorber and the successful construction of an appropriate p-n heterojunction at the electrode-liquid interface for effective charge separation. The demonstration of a low-band-gap and high-performance Sb₂Se₃ photocathode with facile fabrication might facilitate the development of cost-effective PEC devices for wide solar-spectrum utilization.