Nanjing University of Science and Technology

About: Nanjing University of Science and Technology is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Control theory & Catalysis. The organization has 31581 authors who have published 36390 publications receiving 525474 citations. The organization is also known as: Nánjīng Lǐgōng Dàxué & Nánlǐgōng.

All-inorganic quantum-dot light-emitting diodes based on perovskite emitters with low turn-on voltage and high humidity stability

Abstract: Recently, both light-to-electricity and electricity-to-light conversion efficiencies of perovskite achieved a breakthrough, e.g. 22.1% for solar cells and 11.7% for light-emitting diodes (LEDs), so the next fatal problem towards practical application, the device stability, became the key issue in this field. Here, we report all-inorganic LEDs including inorganic perovskite emitters (CsPbBr3) and inorganic charge transport layers (CTLs), with an emphasis on the significantly improved device stability. The quantum dot LEDs (QLEDs) were fabricated according to ITO/NiO/CsPbBr3 QDs/ZnO/Al device configuration. On the one hand, the all-inorganic LED lifetime under 65% humidity corresponding to a 70% electroluminescence (EL) conservation rate can be improved up to 3.5 times when compared with LEDs adopting conventional organic CTLs due to the intrinsic chemical stability of these inorganic CTLs and their less hydrophilic surfaces. Furthermore, as a surprise, the bare all-inorganic LED without encapsulation can work in water for about 20 seconds, which is over 10 times more sustainable than the organic–inorganic LED, which proves the excellent water-isolation ability. On the other hand, the all-inorganic QLEDs show the lowest turn-on voltage of 2.4 V among all the reported CsPbBr3 QLEDs because the inorganic CTLs possess well-matched energy band alignments with CsPbBr3, and hence result in efficient carrier injection. This work paves the way to constructing all-inorganic devices for stable perovskite photovoltaic and light-emitting devices.

Coherence Constrained Graph LSTM for Group Activity Recognition.

Abstract: This work aims to address the group activity recognition problem by exploring human motion characteristics. Traditional methods hold that the motions of all persons contribute equally to the group activity, which suppresses the contributions of some relevant motions to the whole activity while overstates some irrelevant motions. To handle this problem, we present a Spatio-Temporal Context Coherence (STCC) constraint and a Global Context Coherence (GCC) constraint to capture the relevant motions and quantify their contributions to the group activity, respectively. Based on this, we propose a novel Coherence Constrained Graph LSTM (CCG-LSTM) with STCC and GCC to effectively recognize group activity, by modeling the relevant motions of individuals while suppressing the irrelevant motions. Specifically, to capture the relevant motions, we build the CCG-LSTM with a temporal confidence gate and a spatial confidence gate to control the memory state updating in terms of the temporally previous state and the spatially neighboring states, respectively. Besides, an attention mechanism is employed to quantify the contribution of a certain motion by measuring the consistency between itself and the whole activity at each time step. Finally, we conduct experiments on two widely-used datasets to illustrate the effectiveness of the proposed CCG-LSTM compared with the state-of-the-arts methods.

All-solid-state Z-scheme 3,4-dihydroxybenzaldehyde-functionalized Ga2O3/graphitic carbon nitride photocatalyst with aromatic rings as electron mediators for visible-light photocatalytic nitrogen fixation

Abstract: An all-solid-state Z-scheme heterojunction-structured photocatalyst, 3,4-dihydroxybenzaldehyde-functionalized Ga2O3/graphitic carbon nitride (Ga2O3-DBD/g-C3N4), was synthesized using a facile post-grafting strategy via Schiff base chemistry. It was proposed for the first time that aromatic rings served as electron mediators in the Z-scheme photocatalytic system. In addition, the aromatic rings were conducive to the formation of a well-developed combined interface between Ga2O3-DBD and g-C3N4, greatly improving the separation of electrons and holes. The Ga2O3-DBD/g-C3N4 exhibited a wide absorption range, high charge-separation efficiency and high redox potential, thus enhancing its activity and stability for visible-light photocatalytic nitrogen fixation. The reaction mechanism was demonstrated to be that O2 was first reduced to H2O2, which was further oxidized to OH; then, OH reacted with methanol to form CO2−, which facilitated the reduction of N2 to NH3. This study demonstrates a simple and cost-effective approach to synthesize all-solid-state Z-scheme photocatalytic system using the aromatic rings, and this system exhibits great potential for practical applications of visible-light photocatalytic nitrogen fixation.