Superwetting Nanofluids of NiOx-Nanocrystals/CsBr Solution for Fabricating Quality NiOx-CsPbBr3 Gradient Hybrid Film in Carbon-Based Perovskite Solar Cells.

The wettability of precursor solution on substrates is the critical factor for fabricating quality film. In this work, superwetting nanofluids (NFs) of non-stoichiometric nickel oxide (NiOx) nanocrystals (NCs)-CsBr solution are first utilized to fabricate quality NiOx-CsPbBr3 hybrid film with gradient-distributed NiOx NCs in the upper part for constructing hole transport ladder in carbon-based perovskite solar cells (C-PSCs). As anticipated, the crystalline properties (improved crystalline grain diameters and reduced impurity phase) and hole extraction/transport of the NiOx-CsPbBr3 hybrid film are improved after incorporating NiOx NCs into CsPbBr3. This originates from the superb wettability of NiOx-CsBr NFs on substrates and the excellent hole-transport properties of NiOx. Consequently, the C-PSCs with the structure of FTO/SnO2/NiOx-CsPbBr3/C displays a power conversion efficiency of 10.07%, resulting in a 23.6% improvement as compared with the pristine CsPbBr3 cell. This work opens up a promising strategy to improve the absorber layer in PSCs by incorporating NCs into perovskite layers through the use of the superwettability of NFs and by composition gradient engineering.

Robust and Efficient Carbon-Based Planar Perovskite Solar Cells with a CsPbBr3-MoS2 Hybrid Absorber.

Optical response improvement and hole transport/extraction enhancement are critical to enhancing the power conversion efficiency (PCE) of carbon electrode-based perovskite solar cells (C-PSCs) with an absorber of CsPbBr3. In this study, a multifunctional optimization method by embedding MoS2 nanosheets in CsPbBr3 bulk to construct a perovskite-nanosheet hybrid structure was presented. A CsPbBr3-MoS2 hybrid film was fabricated by two-step spin-coating the precursor solutions of PbBr2 and CsBr-MoS2 under an ambient atmosphere, where the aqueous solution with highly distributed MoS2 nanosheets was applied as a solvent of the hybrid precursor solution. MoS2 nanosheets were utilized as a p-type modifier and extra absorber to hybridize with CsPbBr3 for improving the CsPbBr3-carbon interface and light absorption ability of the perovskite layer. As expected, the optical response ability, absorber film quality, and carrier separation/extraction/transport properties of C-PSCs were enhanced significantly by embedding MoS2 nanosheets in CsPbBr3 film, which resulted in enhanced C-PSCs properties. Finally, the C-PSCs with the structure of FTO/SnO2/CsPbBr3-MoS2/C presented a champion PCE of 7.87% (active area: 1 cm2), which demonstrated excellent ambient and operational stability. This study provides an efficient method for constructing ultrastable C-PSCs by hybridizing perovskite and nanosheets.

Periodic Acid Modification of Chemical-Bath Deposited SnO2 Electron Transport Layers for Perovskite Solar Cells and Mini Modules.

Chemical bath deposition (CBD) has been demonstrated as a remarkable technology to fabricate high-quality SnO2 electron transport layer (ETL) for large-area perovskite solar cells (PSCs). However, surface defects always exist on the SnO2 film coated by the CBD process, impairing the devices' performance. Here, a facile periodic acid post-treatment (PAPT) method is developed to modify the SnO2 layer. Periodic acid can react with hydroxyl groups on the surface of SnO2 films and oxidize Tin(II) oxide to Tin(IV) oxide. With the help of periodic acid, a better energy level alignment between the SnO2 and perovskite layers is achieved. In addition, the PAPT method inhibits interfacial nonradiative recombination and facilitates charge transportation. Such a multifunctional strategy enables to fabricate PSC with a champion power conversion efficiency (PCE) of 22.25%, which remains 93.32% of its initial efficiency after 3000 h without any encapsulation. Furthermore, 3 × 3 cm2 perovskite mini-modules are presented, achieving a champion efficiency of 18.10%. All these results suggest that the PAPT method is promising for promoting the commercial application of large-area PSCs.

Synergistic effect of lecithin and alginate, CMC, or PVP in stabilizing curcumin and its potential mechanism.

This work aims to advance the understanding of the synergistic mechanism of lecithin and polymers (alginate, CMC, and PVP) in stabilizing curcumin, with a major focus on understanding the nanocomplex formation process and the main binding energy between molecules. It is demonstrated that lecithin and polymers have a synergistic effect in increasing the thermal acid, light, and digestion stability of curcumin. The potential mechanism is that the hydrophobic parts of curcumin molecules are first anchored at the region of the hydrophobic cavity of lecithin by van der Waals, while the hydrophilic parts are outward and are further encapsulated by hydrophilic polymers by van der Waals and electrostatic interaction to form a protective shell. This study contributes to our understanding of the synergistic mechanism of lecithin, polymers, and hydrophobic compounds, which can promote the synergistic use of lecithin and polymers to prepare nanocomplexes as an important tool for delivering bioactive compounds.

Natural Amino Acid Enables Scalable Fabrication of High-Performance Flexible Perovskite Solar Cells and Modules with Areas over 300 cm2.

Upscaling large-area formamidinium (FA)-based perovskite solar cells (PSCs) has been considered as one of the most promising routes for the commercial applications of this rising photovoltaics technology. Here, a natural amino acid, phenylalanine (Phe), is introduced to regulate the nucleation and crystal growth process of the large-scale coating of FA-based perovskite films. Better film coverage and larger grain sizes are observed after adding Phe. Moreover, it is found that Phe can effectively passivate defects within perovskite films and suppress the nonradiative recombination due to the strong interaction with under-coordinated Pb2+ ions in the perovskite films. Rigid PSCs based on the blade-coated perovskite films containing Phe obtain a champion efficiency of 21.95%. The corresponding unencapsulated devices also exhibit excellent ambient stability, retaining 95% of their initial efficiencies after storage in the glovebox at 20 °C for 1000 h. Further, the strategy is applied to fabricate flexible PSCs and modules on polyethylene terephthalate/indium doped tin oxide substrates via slot-die coating. Phe modified flexible devices achieve outstanding efficiencies of 20.21%, 12.1%, and 11.2% with aperture areas of 0.10, 185, and 333 cm2 , respectively. The strategy here has paved a promising way for the large-scale production of flexible PSCs.

Intelligent dynamic data perturbation OCDM encryption scheme based on cellular neural network and biological genetic encoding.

In this paper, an intelligent dynamic perturbation orthogonal chirp division multiplexing (OCDM) encryption scheme based on cellular neural network and biological genetic encoding for seven-core optical fiber is proposed for the first time to our knowledge. In this scheme, chaotic sequences generated by cellular neural network are employed to construct six masking vectors to achieve six dimensions of ultra-high security encryption. The transmitted bit data is interleaved according to the DNA operation rules. The subcarrier frequency, symbol matrix, and time are scrambled. Because the selected encoding rule, decoding rule, key base sequence, subcarrier frequency, symbol matrix, and scrambling position of time all change dynamically, the robustness against malicious attack is enhanced. Simultaneously, OCDM technology is employed to optimize the system, which effectively improves the anti-interference ability and bit error performance of the system. A 70 Gb /s (7×10 Gb /s) encrypted OCDM signal transmission experiment is carried out on a 2 km 7-core fiber, and an orthogonal frequency division multiplexing (OFDM) signal is transmitted under the same conditions for comparison and verification. The results show that the key space of the newly proposed encryption scheme can reach 101170, and the receiver sensitivity of OCDM is 1.2 dB greater than that of OFDM when the bit error rate is 10-3. The scheme can improve the security of encrypted information and the performance of the system, which is very promising in the optical access network of the future.

Dual-physical layer high-security encryption scheme for seven-core fiber FPS-OFDM-PON.

This paper proposes an encryption scheme for floating probabilistic shaping orthogonal frequency division multiplexing passive optical networks (FPS-OFDM-PON). Four chaotic sequences are generated by the 4D hyperchaotic model for floating probabilistic shaping (FPS) and bubble sort encryption scheme. An experiment is conducted to demonstrate the transmission of a 70Gb/s (7×10Gb/s) FPS-OFDM-PON signal across a 2km weakly coupled 7-core fiber. The keyspace of the 4D hyperchaotic model reaches 10120. The results show that a 1.82 dB gain in receiver sensitivity compared with the conventional uniform 16QAM-OFDM due to the introduction of FPS. When the system is assaulted by an unlawful receiver, the bit error rate (BER) can still remain at 0.49, successfully assuring the system's security. Due to its good transmission and security performance, the scheme has important application prospects in the future optical access network.

Synthesis of (Z)-ß-Chloro-enamides via a Base-Promoted trans-Hydroamidation of Alkynyl Chlorides Using 1,1-Dichloroalkenes as Precursor.

An efficient and general base-promoted reaction of 1,1-dichloroalkenes with secondary sulfonamides and amides for the synthesis of (Z)-ß-chloro-enamides has been described. This reaction exhibits functional group tolerance under simple and mild conditions. Mechanistic study indicated that a stereoselective trans-hydroamidation of alkynyl chlorides generated in situ from 1,1-dichloroalkenes was the key step.