Modulating ultrafast carrier dynamics behavior via vacancy engineering of ReSe2 with Se vacancy for efficient electrochemical activity.

Vacancy engineering has repeatedly proven to be a powerful strategy for manipulating material properties. The important influence of selenium vacancies (V Se) on the physicochemical properties of rhenium diselenide (ReSe 2), exciting applications can be opened in areas such as catalysis and photoelectric devices. However, the effects of V Se on electronic structure, carrier lifetime, and electrochemical activity of ReSe 2 have remained inadequately explored and poorly elucidated. Herein, hydrothermal controlled growth of ReSe 2 with vacancy (V Se -ReSe 2) is used by different synthesis strategies, revealing its growth mechanism. An ethanol-assisted hydrothermal method based on carbon paper was used to adjust the V Se concentration by changing the time parameters. Mediated excitonic effects in the transient absorption (TA) spectroscopy and photoluminescence response of ReSe 2 regulated by V Se were characterized. The defect level (DL) leads V Se -ReSe 2 to produce a unique defect emission peak, and the V Se -mediated exciton dynamics problem was discussed. Moreover, the TA result of V Se -ReSe 2 shows that high V Se concentration prolongs carrier lifetime and causes high carrier separation efficiency and electron utilization. The electrocatalytic hydrogen evolution reaction of ReSe 2 catalyst revealed the ability of V Se concentration to regulate the electrochemical activity, which provides ideas for vacancy management catalyst performance. The presence of DL and the reduction of band gap are indicated by density functional theory, which confirms the regulatory effect of V Se concentration on the electronic structure of ReSe 2. This work proffers an optimal solution strategy for hydrothermal preparation of ReSe 2 , which demonstrates the feasibility of regulating electrochemical activity by vacancy engineering, and the excellent performance of V Se -ReSe 2 makes it show great potential in many fields such as water cracking and physical devices. [Display omitted] • A regulation strategy for the successful construction of V Se rich ReSe 2 nanoflowers was developed. • DFT investigated the reduction of the band gap and orbital contribution of ReSe 2 regulated by V Se. • Mediated excitonic effects in the TA and PL response of ReSe 2 regulated by V Se were analyzed. • The effectively regulate the HER activity of V Se -ReSe 2 were analyzed. Vacancy engineering is powerful for manipulating material properties. Selenium vacancies (V Se) exert significantly impact on the physicochemical properties of rhenium diselenide (ReSe 2), triggering applications in catalysis and photoelectric devices. However, the effects on electronic structure, carrier lifetime, and electrochemical activity are inadequately explored and poorly elucidated. Herein, hydrothermal-controlled growth of ReSe 2 with V Se is synthesized by different strategies. The ethanol-assisted hydrothermal method can adjust V Se concentration of ReSe 2 on carbon paper by time parameters. Mediated excitonic effects were characterized in the transient absorption spectroscopy and photoluminescence of V Se -regulated ReSe 2. The defect level produces unique defect emission peak, and the V Se -mediated exciton dynamics problem was discussed. The transient absorption result shows that high V Se concentration can optimize carrier lifetime, carrier separation efficiency, and electron utilization. The electrocatalytic hydrogen evolution reaction of ReSe 2 catalyst revealed the electrochemical activity regulation by V Se concentration, which provides ideas for enhancing catalyst performance. Density functional theory result confirms the role of selenium vacancies in the regulation of the electronic structure of ReSe 2. This work proffers an optimal solution strategy for hydrothermal preparation of ReSe 2 , and demonstrates the feasibility of regulating electrochemical activity by vacancy engineering. The excellent performance is beneficial for water cracking and physical devices. [ABSTRACT FROM AUTHOR]