Wooseok Yang

To accelerate the deployment of hydrogen produced by renewable solar energy, several technologies have been competitively developed, including photoelectrochemical (PEC), photocatalytic, and photovoltaic-electrolysis routes. In this review, we place PEC in context with these competing technologies and highlight key advantages of PEC systems. After defining the unique performance metrics of the PEC water splitting system, recently developed strategies for enhancing each performance metric, such a

Determining cost-effective semiconductors exhibiting desirable properties for commercial photoelectrochemical water splitting remains a challenge. Herein, we report a Sb₂Se₃ semiconductor that satisfies most requirements for an ideal high-performance photoelectrode, including a small band gap and favourable cost, optoelectronic properties, processability, and photocorrosion stability. Strong anisotropy, a major issue for Sb₂Se₃, is resolved by suppress

Solar-energy conversion by photoelectrochemical (PEC) devices is driven by the separation and transfer of photogenerated charge carriers. Thus, understanding carrier dynamics in a PEC device is essential to realizing efficient solar-energy conversion. Here, we investigate time-resolved carrier dynamics in emerging low-cost Sb₂Se₃ nanostructure photocathodes for PEC water splitting. Using terahertz spectroscopy, we observed an initial mobility loss within tens of picoseconds

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 tech

To realize economically competitive hydrogen production through photoelectrochemical (PEC) water splitting, it is essential to develop an efficient photoelectrode consisting of earth-abundant constituents in conjunction with low-cost solution processing. Cu2ZnSnS4 (CZTS) has received significant attention as a promising photocathode owing to its abundance and good absorption properties. However, the efficiency of the solution-processed CZTS photocathode is not yet comparable to its counterparts.

Abstract Sb 2 Se 3 has recently spurred great interest as a promising light‐absorbing material for solar energy conversion. Sb 2 Se 3 consists of 1D covalently linked nanoribbons stacked via van der Waals forces and its properties strongly depend on the crystallographic orientation. However, strategies for adjusting the anisotropy of 1D Sb 2 Se 3 nanostructures are rarely investigated. Here, a novel approach is presented to fabricate 1D Sb 2 Se 3 nanostructure arrays with different aspect ratios

Judicious balancing of photon utilization between semitransparent nanopillar perovskite solar cells and multilayer Sb₂Se₃photocathodes enables high efficiency water splitting with good stability.

Abstract Although electrochemical impedance spectroscopy (EIS) is a powerful technique for investigating optoelectronic devices, realistic equivalent circuit (EC) models suitable for multi‐layered water splitting electrodes have rarely been reported due to their complex nature. In the present study, the utility of the EIS method for investigating multi‐layered photocathodes for photoelectrochemical water splitting is demonstrated. By analyzing the EIS data of TiO 2 ‐coated Sb 2 Se 3 photocathode

In the quest for higher efficiency and lower cost solar energy conversion devices, new light absorber materials are being intensively researched. With their attractive optical and electrical properties, metal chalcogenide materials have emerged as promising candidates for these next-generation light absorbers. In this review, we survey studies on chalcogenide light absorbers having a simple binary composition, namely, Cu2S, SnS, GeSe, WSe2, Sb2S3, and Sb2Se3. Each material has its own unique str

Water splitting is crucial for green hydrogen production, yet gas bubble dynamics has been underexplored until recently. Bubbles reduce electrochemically active surface area, increase overpotentials, and cause optical losses in (photo)electrochemical systems. Recent advancements in both theoretical understanding and experimental techniques have led to a deeper appreciation of the role that bubble dynamics plays in improving water splitting performance. The present review revisits the fundamental

The advantages of antimony triselenide (Sb₂Se₃) over other semiconducting materials for solar-to-hydrogen conversion are highlighted. Rapid recent advances in Sb₂Se₃ photocathode technology are summarized and future research directions are discussed.

The continuous depletion of fossil fuels and the effects of climate change have encouraged prompt action to attain carbon neutrality. Technologies that transform and store renewable energy are crucial for creating a sustainable society, which is independent of fossil fuels. In this regard, electrochemical water splitting based on the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is an attractive technique for producing carbon-free hydrogen fuels. Additionally, rechargeabl

Although copper-based chalcopyrite materials such as CuInS2 have been considered promising photocathodes for solar water splitting, the fabrication route for a nanostructure with vertical orientation has not yet been developed. Here, a fabrication route for vertically aligned CuInS2 nanorod arrays from an aqueous solution using anodic aluminum oxide template-assisted growth and transfer is presented. The nanorods exhibit a phase-pure CuInS2 chalcopyrite structure and cathodic photocurrent respon

To realize practical solar hydrogen production, a low-cost photocathode with high photocurrent density and onset potential should be developed. Herein, an efficient and stable overall photoelectrochemical tandem cell is developed with a Cu₃ BiS₃ -based photocathode. By exploiting the crystallographic similarities between Bi₂ S₃ and Cu₃ BiS₃ , a one-step solution process with two sulfur sources is used to prepare the Bi₂