Search

Metal halide perovskites have triggered numerous studies in the application of optoelectronic devices. In this work, we incorporated Ce3+ ions into the MAPbBr3 perovskite to extend the photoluminescence spectrum from the green light region to red light region, which can be attributed to the dopant-induced self-trapped exciton (STE) emission. Furthermore, the non-equivalent substitution of Ce3+ ions for the Pb2+ ions can result in extra electrons, thus can change the type of dominant carriers and improve the carrier mobility. The MAPbBr3:Ce based photodetector exhibited a broadband photodetection capability over a wide range from 340 nm to 650 nm. In addition, after doping Ce3+ ions, the maximum device responsivity, detectivity and external quantum efficiency were efficiently improved. These results provide a new approach to highly-efficient and broadband-detecting photoconductive photodetectors. [ABSTRACT FROM AUTHOR]

Nickel oxide (NiOX) has a crucial role in enhancing the efficiency and stability of p‐i‐n inverted perovskite solar cells (PSCs), which hold great potential for commercialization. However, improving contact passivation between perovskites and NiOX is a challenge due to a hindered buried interface. In order to address this issue, self‐assembled monolayers (SAMs) are introduced as a buffer layer to prevent direct contact and non‐radiative recombination. While, the large dipole moment of SAMs increases the work function of NiOX, which is crucial for enhancing hole transport performance, given the low interfacial potential barrier for hole transfer. By a combination of the first‐principles calculations, drive‐level capacitance profiling, and transient absorption spectrum characterization, the understanding of the ion‐dipole interactions and interface passivation mechanism of potassium fluoride (KF) ultra‐thin buffer layer between SAMs and perovskites is provided. The efficiency of inverted PSCs as high as 23.25% is obtained, and the unencapsulated devices kept 90% of initial efficiency following 1400 h aging under nitrogen, which demonstrate remarkable long‐term stability as well. This novel strategy highlights the significance of SAMs dipole moment at the NiOX/perovskites interface and provides a new approach to address buried interfaces for high‐efficiency and long‐term stability in inverted PSCs. [ABSTRACT FROM AUTHOR]

Thermal transport is of grave importance in many high-value applications. Heat dissipation can be improved by utilizing liquid metals as thermal interface materials. Yet, liquid metals exhibit corrosivity towards many metals used for heat sinks, such as aluminum, and other electrical devices (i.e., copper). The compatibility of the liquid metal with the heat sink or device material as well as its long-term stability are important performance variables for thermal management systems. Herein, the compatibility of the liquid metal Galinstan, a eutectic alloy of gallium, indium, and tin, with diamond coatings and the stability of the liquid metal in this environment are scrutinized. The liquid metal did not penetrate the diamond coating nor corrode it. However, the liquid metal solidified with the progression of time, starting from the second year. After 4 years of aging, the liquid metal on all samples solidified, which cannot be explained by the dissolution of aluminum from the titanium alloy. In contrast, the solidification arose from oxidation by oxygen, followed by hydrolysis to GaOOH due to the humidity in the air. The hydrolysis led to dealloying, where In and Sn remained an alloy while Ga separated as GaOOH. This hydrolysis has implications for many devices based on gallium alloys and should be considered during the design phase of liquid metal-enabled products. [ABSTRACT FROM AUTHOR]

Directed liquid metal (gallium‐based) manipulation and actuation are paramount for copious applications, including soft robotics, soft electronics, and targeted drug delivery. Although there are several strategies available to achieve mobility of liquid metals in a "wet" environment. Strategies to achieve and improve mobility of liquid metal droplets and puddles in a "dry" environment are scarce and rely on metallophobic surface design or liquid metal marbles. Here, high mobility of Galinstan is elucidated by combining metallophobic surface design and vertical vibrations. Vibration frequencies between 20 and 30 Hz are conducive to droplet movement and threshold inclination angles of 0.5° to 1° are observed upon actuation by these vibrations. The method itself is applicable for a wide range of droplet sizes (30 and 2000 µL) and very robust. The droplet movement typically comprises of periodic receding and advancing of the droplet and commences via a rolling mechanism rather than a gliding mechanism. Finally, it is shown that small (0.5 mm height) obstacles can be traversed by this method, indicating that it can be used in concert with other strategies, such as surface structuring strategies, which open up pathways for mobility and controlled actuation of liquid metal droplets in air. [ABSTRACT FROM AUTHOR]

Perovskite materials with excellent optical and electronic properties have huge potential in the research field of photodetectors. Constructing heterojunctions and promoting carrier transportation are significant for the development of perovskite-based optoelectronics devices with high performances. Herein, we demonstrated a CsPbBr3/SnO2 heterojunction photodetector and improved the device performances through post-annealing treatment of SnO2 film. The results indicated that the electrical properties of SnO2 films will make an important impact on carrier extraction, especially for type-II heterojunction. As the electrons transfer layer in CsPbBr3/SnO2 type-II heterojunction, defects related to oxygen vacancy should be the key factor to affect carrier concentration, induce carriers' limitation and recombination rate. Under proper annealing temperature for SnO2 layer, the recombination rate can decrease to 1.37 × 1021 cm3 s and the spectral responsivity will be highly increased. This work can enhance the understanding on the photoresponse of perovskite photodetectors, and will be helpful for the further optimization and design of optoelectronic devices based on the perovskite heterojunction. [ABSTRACT FROM AUTHOR]

Constructing heterojunction is an attractive strategy for promoting photoelectrochemical (PEC) performance in water splitting and organic pollutant degradation. Herein, a novel porous BiVO4/Boron-doped Diamond (BiVO4/BDD) heterojunction photoanode containing masses of ultra-micro electrodes was successfully fabricated with an n-type BiVO4 film coated on a p-type BDD substrate by magnetron sputtering (MS). The surface structures of BiVO4 could be adjusted by changing the duration of deposition (Td). The morphologies, phase structures, electronic structures, and chemical compositions of the photoanodes were systematically characterized and analyzed. The best PEC activity with the highest current density of 1.8 mA/cm2 at 1.23 VRHE was achieved when Td was 30 min, and the sample showed the highest degradation efficiency towards tetracycline hydrochloride degradation (TCH) as well. The enhanced PEC performance was ascribed to the excellent charge transport efficiency as well as a lower carrier recombination rate, which benefited from the formation of BiVO4/BDD ultra-micro p-n heterojunction photoelectrodes and the porous structures of BiVO4. These novel photoanodes were expected to be employed in the practical PEC applications of energy regeneration and environmental management in the future. [ABSTRACT FROM AUTHOR]

High power conversion efficiencies (PCEs) in perovskite solar cells (PSCs) have always been awe-inspiring, but perovskite films scalability is an exacting precondition for PSCs commercial deployment, generally unachievable through the antisolvent technique. On the contrary, in the two-step sequential method, the perovskite's uncontrolled crystallization and unnecessary PbI 2 residue impede the device's performance. These two issues motivated to empower the PbI 2 substrate with orthorhombic RbPbI 3 crystal seeds, which act as grown nuclei and develop orientated perovskites lattice stacks, improving the perovskite films morphologically and reducing the PbI 2 content in eventual perovskite films. Thence, achieving a PCE of 24.17% with suppressed voltage losses and an impressive life span of 1140 h in the open air., (© 2023 Wiley-VCH GmbH.)

Perovskite materials with excellent optical and electronic properties have huge potential in the research field of photodetectors. Constructing heterojunctions and promoting carrier transportation are significant for the development of perovskite-based optoelectronics devices with high performances. Herein, we demonstrated a CsPbBr 3 /SnO 2 heterojunction photodetector and improved the device performances through post-annealing treatment of SnO 2 film. The results indicated that the electrical properties of SnO 2 films will make an important impact on carrier extraction, especially for type-II heterojunction. As the electrons transfer layer in CsPbBr 3 /SnO 2 type-II heterojunction, defects related to oxygen vacancy should be the key factor to affect carrier concentration, induce carriers' limitation and recombination rate. Under proper annealing temperature for SnO 2 layer, the recombination rate can decrease to 1.37 × 10 21 cm 3 s and the spectral responsivity will be highly increased. This work can enhance the understanding on the photoresponse of perovskite photodetectors, and will be helpful for the further optimization and design of optoelectronic devices based on the perovskite heterojunction., (© 2023 IOP Publishing Ltd.)