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The fundamental study on photo(electro)catalytic reactions is central for the potential application in solving energy and environmental issues. However, the exciton effect, which affects their photo(electro)catalytic performance especially in organic and low-dimensional inorganic materials, is less explored. Therefore, it is necessary to investigate the exciton dynamics involved in the photo(electro)catalytic process, and the strategies for modulating exciton dynamics are also needed for improving the photo(electro)catalytic performance. In this review, we introduce the exciton dynamics and main exciton characterization techniques, and summarize the mechanisms for modulating exciton dynamics in photo(electro)catalysis. Finally, current challenges and future possible developments for exciton dynamics in the photo(electro)catalytic process are discussed. We hope this review will provide insights on the exciton dynamics in the photo(electro)catalysis, thus inspiring more researches on the materials with strong exciton effect in photo(electro)catalytic applications.

Simultaneously improving the efficiency and stability on a large scale is significant for the development of photoelectrochemical (PEC) water splitting systems. Here, we demonstrated a novel design of GaP/GaPN core/shell nanowire (NW) decorated p-Si photocathode for improved PEC hydrogen production performance compared to that of bare p-Si photocathode. The formation of the p-n junction between p-Si and GaP NW promotes charge separation, and the lower conduction band position of GaPN relative to that of GaP further facilitates the transfer of photogenerated electrons to the electrode surface. In addition, the NW morphology both shortens the carrier collection distance and increases the specific surface area, which result in superior reaction kinetics. Moreover, introduction of N in GaP is beneficial for enhancing the light absorption as well as stability. Our efficient and facile strategy can be applied to other solar energy conversion systems as well.

Graphene is an attractive material for photodetection and optoelectronic applications because it offers a broad spectral bandwidth and ultrafast response speed. However, because of the broad light absorption characteristic, graphene has a lack of selectivity to the wavelength, which limits the performance of graphene-based photodetectors. Here, we demonstrate a novel hybrid photodetector with monolayer graphene covered with an ultrathin film of surface covalent organic frameworks (COFs) with variable structures as the light-harvesting materials. Photodetectors based on surface COF-G show enhanced responsivity in comparison with unmodified graphene and graphene modified with monomers. The submolecular resolution of scanning tunneling microscopy allows us to get a direct insight into the relationship between the microscopic interfacial structure and the performance of the device. We prove that the enhancement in the device performance is directly related with the orderliness of surface COFs, which influences the interfacial charge transfer by tuning π-π stacking between surface COF and graphene.

Graphene, a new material for the electron-device community, has many extraordinary properties. Especially, it provides a perfect platform to explore the unique electronic property in absolutely two-dimensions. However, most electronic applications are handicapped by the absence of a semiconducting gap in pristine graphene. To control the semiconducting properties of graphene, doping is regarded as one of the most feasible methods. Herein, a brief review is given on the recent research progress of graphene doping, which is roughly divided into three categories: First, the hetero atom doping, including arc discharge, chemical vapor deposition, electrothermal reaction and ion-irradiation approaches; Second, the chemical modification strategy; Third, the method of electrostatic field tuning. In addition, the various potential applications of the above doping methods are also introduced.

A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical (PEC) water splitting is central to improving its performance. Herein, taking the Si-based photoanodes (n+p-Si/SiOx/Fe/FeOx/MOOH, M = Fe, Co, Ni) as a model system, we investigate the effect of the transition-metal electrocatalysts on the oxygen evolution reaction (OER). Among the photoanodes with the three different electrocatalysts, the best OER activity, with a low-onset potential of ∼1.01 VRHE, a high photocurrent density of 24.10 mA cm−2 at 1.23 VRHE, and a remarkable saturation photocurrent density of 38.82 mA cm−2, was obtained with the NiOOH overlayer under AM 1.5G simulated sunlight (100 mW cm−2) in 1 M KOH electrolyte. The optimal interfacial engineering for electrocatalysts plays a key role for achieving high performance because it promotes interfacial charge transport, provides a larger number of surface active sites, and results in higher OER activity, compared to other electrocatalysts. This study provides insights into how electrocatalysts function in water-splitting devices to guide future studies of solar energy conversion.