Ultrastable halide perovskite CsPbBr3 photoanodes achieved with electrocatalytic glassy-carbon and boron-doped diamond sheets

Engineering perovskite solar cells for photovoltaic and photoelectrochemical systems: strategies for enhancing efficiency and stability

Solar-driven fuel production, including photovoltaic-electrochemical (PV-EC) and photoelectrochemical (PEC) water splitting as well as CO2 reduction reaction (CO2RR), presents a viable approach to mitigating carbon emissions. One of the major obstacles in developing efficient PV-EC and PEC systems lies in identifying suitable photoabsorbers that can effectively harness solar energy while maintaining stability under operating conditions. Despite their intrinsic instability in such environments, halide perovskites have garnered significant attention as promising photoabsorbers due to their exceptional optoelectronic properties, which are essential for facilitating efficient electrochemical reactions. This review first provides a concise overview of the mechanisms underlying water splitting and the CO2RR, followed by an examination of the structural configurations and performance evaluation metrics of PV-EC and PEC systems. Next, the design and engineering of perovskite solar cells (PSCs) are explored, with an emphasis on optimizing light absorption, charge transport layer engineering, and addressing stability issues. Recent advancements in enhancing the efficiency and operational stability of PV-EC and PEC systems incorporating PSCs are then summarized. Finally, key challenges currently being addressed in the field are discussed, along with perspectives on future research directions. This review aims to support researchers in further advancing this technology toward the commercial production of green hydrogen.

Halide Perovskite Photocatalysts for Clean Fuel Production and Organic Synthesis: Opportunities and Challenges

The need to constrain the use of fossil fuels causing global warming is motivating the development of a variety of photocatalysts for solar-to-fuel generation and chemical synthesis. In particular, semiconductor-based photocatalysts have been extensively exploited in solar-driven organic synthesis, carbon dioxide (CO2) conversion into value-added products, and hydrogen (H2) generation from water (H2O) splitting. Recently, metal halide perovskites (MHPs) have emerged as an important class of semiconductors for heterogeneous photocatalysis owing to their interesting properties. Despite key issues with long-term stability and degradation in polar solvents due to their ionic character, there has been significant progress in halide perovskite-based photocatalysts with improving their stability and performance in the gas and liquid phases. This review discusses the state-of-the-art for using halide perovskite-based photocatalysts and photoelectrocatalysis in hydrogen production from water and halogen acid solutions, CO2 reduction into value-added chemicals, and various organic chemical transformations. The different types of halide perovskites used, design strategies to overcome the instability issues in polar solvents, and the efficiencies achieved are discussed. Furthermore, the outstanding challenges associated with the use of polar electrolytes and how the stability and performance can be improved are discussed.

Scalable and durable module-sized artificial leaf with a solar-to-hydrogen efficiency over 10

An artificial leaf mimicking the function of a natural leaf has recently attracted significant attention due to its minimal space requirement and low cost compared to wired photoelectrochemical and photovoltaic-electrochemical systems for solar hydrogen production. However, it remains a challenge to achieve a practical-size solar water-splitting device that can fulfill the criteria of a solar-to-hydrogen conversion efficiency above 10%, long-term durability, and scalability. Here, we develop 1 cm2 perovskite-based photoelectrodes using a defect-less, chlorine-doped formamidinium lead triiodide as photo-absorber and ultraviolet-insensitive tin oxide as an electron transport layers. This device is encapsulated using electrocatalyst-deposited nickel foils, which demonstrates high photocurrent density and high stability for 140 h. Ultimately, we fabricate a scalable mini-module-sized artificial leaf (16 cm2) consisting of a side-by-side/parallel configuration of photoanode and photocathode architecture integrated with a 4 × 4 array of 1 cm2 photoelectrodes, which maintains a stable 'module-level' solar-to-hydrogen efficiency of 11.2% in an unbiased solar water-splitting under 1-sun illumination.

Semiconductor-Based Photoelectrocatalysts in Water Splitting: From the Basics to Mechanistic Insights-A Brief Review

Hydrogen and oxygen serve as energy carriers that can ease the transition of energy due to their high energy densities. Nonetheless, their production processes entail the development of efficient and low-cost storage and conversion technologies. In this regard, photoelectrocatalysts are materials based on the photoelectronic effect where electrons and holes interact with H2O, producing H2 and O2, and in some cases, this is achieved with acceptable efficiency. Although there are several reviews on this topic, most of them focus on traditional semiconductors, such as TiO2 and ZnO, neglecting others, such as those based on non-noble metals and organic ones. Herein, semiconductors like CdSe, NiWO4, Fe2O3, and others have been investigated and compared in terms of photocurrent density, band gap, and charge transfer resistance. In addition, this brief review aims to discuss the mechanisms of overall water-splitting reactions from a photonic point of view and subsequently discusses the engineering of material synthesis. Advanced composites are also addressed, such as WO3/BiVO4/Cu2O and CN-FeNiOOH-CoOOH, which demonstrate high efficiency by delivering photocurrent densities of 5 mAcm-2 and 3.5 mA cm-2 at 1.23 vs. RHE, respectively. Finally, the authors offer their perspectives and list the main challenges based on their experience in developing semiconductor-based materials applied in several fields. In this manner, this brief review provides the main advances in these topics, used as references for new directions in designing active materials for photoelectrocatalytic water splitting.