No abstract

The development of an efficient, robust, and low-cost catalyst for water electrolysis is critically important for renewable energy conversion. Herein, we achieve a significant improvement in electrocatalytic activity for both the oxygen-evolution reaction (OER) and the hydrogen-evolution reaction (HER) by constructing a novel hierarchical PrBa 0.5 Sr 0.5 Co 2 O 5+δ (PBSC)@FeOOH catalyst. The optimized PBSC@FeOOH-20 catalyst consisted of layered perovskite PBSC nanorods and 20 nm thick amorphous FeOOH nanoflakes exhibiting an excellent electrocatalytic activity for the OER and the HER in 0.1 M KOH media, delivering a current density of 10 mA cm −2 at overpotentials of 390 mV for the OER and 280 mV for the HER, respectively. The substantially enhanced performance is probably attributed to the hierarchical nanostructure, the good charge-transfer capability, and the strong electronic interactions of FeOOH and PBSC. Importantly, an alkaline electrolyzer-integrated PBSC@FeOOH-20 catalyst as both the anode and cathode shows a highly active overall water splitting with a low voltage of 1.638 V at 10 mA cm −2 and high stability during continuous operation. This study provides new insights into exploring efficient bifunctional catalysts for overall water splitting, and it suggests that the rational design of the oxyhydroxide/perovskite heterostructure shows great potential as a promising type of electrocatalysts.

No abstract

No abstract

Estimating 3D hand poses from RGB images is essential to a wide range of potential applications, but is challenging owing to substantial ambiguity in the inference of depth information from RGB images. State-of-the-art estimators address this problem by regularizing 3D hand pose estimation models during training to enforce the consistency between the predicted 3D poses and the ground-truth depth maps. However, these estimators rely on both RGB images and the paired depth maps during training. In this study, we propose a conditional generative adversarial network (GAN) model, called Depth-image Guided GAN (DGGAN), to generate realistic depth maps conditioned on the input RGB image, and use the synthesized depth maps to regularize the 3D hand pose estimation model, therefore eliminating the need for ground-truth depth maps. Experimental results on multiple benchmark datasets show that the synthesized depth maps produced by DGGAN are quite effective in regularizing the pose estimation model, yielding new state-of-the-art results in estimation accuracy, notably reducing the mean 3D endpoint errors (EPE) by 4.7%, 16.5%, and 6.8% on the RHD, STB and MHP datasets, respectively.

due to the spin selection rule. How to bring the dark triplets into bright is one of the most important issues in the field of OLEDs. [2] Besides the strategies of phosphorescence [3,4] and thermally activated delayed fluorescence [5][6][7][8] (TADF), triplettriplet annihilation (TTA) up-conversion, also known as triplet fusion, is an alternative efficient mechanism to utilize the dark triplets. [9][10][11][12][13][14] In TTA process, two triplet excitons fusion and create one highenergy singlet exciton, and finally produce a high-energy photon indirectly. [15] Moreover, the bimolecular nature predicts a faster TTA at high exciton density. This unique property could ultimately solve the problem of efficiency roll-off, which is commonly observed in OLEDs with TADF or phosphorescence emitters. These features make TTA process attracting much attentions in OLEDs recently. [16][17][18][19][20][21][22][23] The dynamics of TTA has been tremendously addressed with sensitizing mechanism. [24][25][26] For the sensitization case, triplets are first formed on the sensitizer and then transferred to TTA molecules where the TTA process takes place. The resultant fluorescence via TTA process quadratically increases at the weak excitation range, and linearly increases at the strong excitation. The non-linear properties are also found in OLEDs with charge-transfer (CT) state as triplet sensitizer. [27][28][29] However, besides the role of sensitizing, the CT states could simultaneously greatly quench the singlet excitons. Further, the exciton cycle occurs between singlets and triplets through TTA and singlet quenching processes. The quenching effect together with exciton cycle greatly reduces the exciton utilization. Resultantly, the devices working in sensitization mechanism generally exhibit extremely low efficiency. [30] To eliminate the exciton cycle and quenching effect, OLEDs with an emissive layer capable of pure TTA are desirable for achieving high efficiency. In this case, both singlet and triplet excitons are directly formed on TTA molecules. The singlet excitons can directly generate EL without being quenching. Meanwhile, the triplets could indirectly produce EL through TTA up-conversion channel. The energy loss via exciton cycle could be avoided by eliminating the intermediate CT states. Since the triplets are directly formed on TTA molecules, this approach is referred to as non-sensitization TTA to discriminate from sensitizing Triplet-triplet annihilation (TTA) up-conversion is an effective way to utilize triplet excitons in organic light-emitting diodes (OLEDs). However, the parameters characterizing the triplet excitons and relevant TTA process in OLEDs under working conditions have not been quantified. Here, an in situ method is established to map these parameters for further ascertaining their impact on device efficiency. The physical parameters, including triplet recombination rate, TTA rate, typical current J TTA , and saturated ratio, can be in situ quantified by transient electroluminescence technique. The ex...

Manipulating molecular orbital properties of excited state, and then the relevant relaxation processes, can greatly alter the emission behaviors of luminophores. Herein we reported a vivid example of this respect...

No abstract