Search

In the present study, we carried out a comprehensive investigation of glycoside hydrolase (GH) 46 model-chitosanases based on cleavage specificity classification to understand their unknown bifunctional activity. We for the first time show that GH46 chitosanase CsnMHK1 from

Narrow-band-gap organic semiconductors have emerged as appealing near-infrared (NIR) sensing materials by virtue of their unique optoelectronic properties. However, their limited carrier mobility impedes the implementation of large-area, dynamic NIR sensor arrays. In this work, high-performance inorganic-organic hybrid phototransistor arrays are achieved for NIR sensing, by taking advantage of the high electron mobility of In

Chitosanase, a glycoside hydrolase (GH), catalyzes the cleavage of β-1,4-glycosidic bonds in polysaccharides and is widely distributed in nature. Many organisms produce chitosanases, and numerous chitosanases in the GH families have been intensely studied. The reported chitosanases mainly cleaved the inter-glucosamine glycosidic bonds, while substrate specificity is not strictly unique due to the existence of bifunctional or multifunctional activity profiles. The promiscuity of chitosanases is essential for the different pathways of biomass polysaccharide conversion and understanding of the chitosanase evolutionary process. However, the reviews for this aspect are completely unknown. This review provides an overview of the promiscuous activities, also considering the substrate and product specificity of chitosanases observed to date. These contribute to important implications for the future discovery and research of promiscuous chitosanases and applications related to biomass conversion. KEY POINTS: • The promiscuity of chitosanases is reviewed for the first time. • The current review provides insights into the substrate specificity of chitosanases. • The mode-product relationship and prospect of promiscuous chitosanases are highlighted.

Semitransparent organic solar cells (ST-OSCs) have drawn great attention due to their wide application, such as smart windows, greenhouses and building integrated photovoltaics. The ternary strategy is often considered an useful way to enhance device performance due to improve the attracting or retracting morphology. Here, non-fullerene small molecule (Y8) with electron-deficient core as the center unit and a novel PBDTTT-type low-bandgap polymer (PCE10) were chosen to fabricate ST-OSCs according to the principle of more closely matched energy levels. With the introduction of indene-C60bisadduct (ICBA) as third component, opaque organic solar cells with a power conversion efficiency (PCE) of 12.86% and ST-OSCs with a PCE of 10.46% were obtained by using spin coating after optimization. The average visible transmittance of ST-OSCs is up to 26.56%. By the blade coating technique, 9.52% PCE is achieved for ST-OSCs, which is the highest value reported to date. These results show that it's higher efficiency to improve the performance of ST-OSCs through ternary strategy. And the blade coating technique has a promising application prospect for mass manufacturing ST-OSCs.

Combining the high stability under UV light of the wide bandgap (WBG) perovskite solar cells (pero-SCs) and the broad near-infrared absorption spectra of the narrow bandgap (NBG) organic solar cells (OSCs), the perovskite/organic tandem solar cells (TSCs) with the WBG pero-SC as front cell and the NBG OSC as rear cell have attracted attention . However, the photovoltaic performance of the perovskite/organic TSCs needs to be further improved. Herein, nonradiative charge recombination loss is reduced through bulk defect passivation in the WBG pero-SC front subcell and broadening the range of absorption spectra of the NBG OSC rear cell. For the WBG pero-SCs, an organic cation chloro-formamidinium is introduced into FA

Two polymers J75 and J76 with selenophene instead of thiophene on the conjugated side chain of benzodithiophene (BDT) unit or π bridges of polymer J71 were designed and synthesized, for investigating the effect of selenophene substitution on the photovoltaic performance of the conjugated polymer donors in comparison with J71. The selenophene π bridges in J76 can narrow optical band gap and red-shift absorption of the polymer film by ca. 25 nm, but the highest occupied molecular orbital (HOMO) energy level (EHOMO) of J76 is up-shifted slightly by 0.04 eV. Two typical electron acceptors of fullerene derivative PC71BM and the nonfullerene acceptor m-ITIC were used to investigate photovoltaic performance of the polymer donors. For the PC71BM-based polymer solar cells (PSCs), J76 with selenophene π bridges shows the best power-conversion efficiency (PCE) of 8.40% in comparison with the J71-based device (PCE = 6.79%), benefitted from the red-shifted absorption, larger coherence length, purer average domains, an...

Tandem organic solar cells are based on the device structure monolithically connecting two solar cells to broaden overall absorption spectrum and utilize the photon energy more efficiently. Herein, we demonstrate a simple strategy of inserting a double bond between the central core and end groups of the small molecule acceptor Y6 to extend its conjugation length and absorption range. As a result, a new narrow bandgap acceptor BTPV-4F was synthesized with an optical bandgap of 1.21 eV. The single-junction devices based on BTPV-4F as acceptor achieved a power conversion efficiency of over 13.4% with a high short-circuit current density of 28.9 mA cm−2. With adopting BTPV-4F as the rear cell acceptor material, the resulting tandem devices reached a high power conversion efficiency of over 16.4% with good photostability. The results indicate that BTPV-4F is an efficient infrared-absorbing narrow bandgap acceptor and has great potential to be applied into tandem organic solar cells., Development of tandem organic solar cells has been limited by the choice of near-infrared absorbing materials for the rear cell. Here, the authors report a simple strategy to extend the conjugation length of acceptor Y6 and broaden its absorption range to near-infrared region. A tandem organic solar cell with efficiency of 16.4% was achieved.

A series of all-conjugated polythiophene diblock copolymers containing hydrophobic (hexyl) and hydrophilic (triethylene glycol) side chains were synthesized via a nickel-catalyzed quasi-living polymerization. The correlations between block ratios and the self-assembled nanostructures of the block copolymers in thin films and in various solutions were examined. The copolymers dispersed in water via a slow dialysis method produced molecular-level self-assembled core–shell nanospheres with a crystallized hydrophobic core and a hydrophilic amorphous shell, which was proved by TEM images. The size and quantum yield of polymer micelles could be easily tuned via the block ratio of copolymers. The resulting core–shell nanospheres of BP40 composed of 40 mol% P3HT blocks with an average size of 120 nm exhibit high quantum yield (19% in aqueous medium), good photostability and low cytotoxicity. Utilized as a far-red/near-infrared (FR/NIR) cellular probe, BP40 is internalized efficiently by the cells and accumulated in the cytoplasm to give bright fluorescence.

Herein, the ability to optimize the morphology and photovoltaic performance of poly(3-hexylthiophene) (P3HT)/ZnO hybrid bulk-heterojunction solar cells via introducing all-conjugated amphiphilic P3HT-based block copolymer (BCP), poly(3-hexylthiophene)-block-poly(3-triethylene glycol-thiophene) (P3HT-b-P3TEGT), as polymeric additives is demonstrated. The results show that the addition of P3HT-b-P3TEGT additives can effectively improve the compatibility between P3HT and ZnO nanocrystals, increase the crystalline and ordered packing of P3HT chains, and form optimized hybrid nanomorphology with stable and intimate hybrid interface. The improvement is ascribed to the P3HT-b-P3TEGT at the P3HT/ZnO interface that has strong coordination interactions between the TEG side chains and the polar surface of ZnO nanoparticles. All of these are favor of the efficient exciton dissociation, charge separation and transport, thereby, contributing to the improvement of the efficiency and thermal stability of solar cells. These observations indicate that introducing all-conjugated amphiphilic BCP additives can be a promising and effective protocol for high-performance hybrid solar cells.

Herein, we have developed a new poly(3-hexylthiophene) (P3HT)-based diblock copolymeric additive bearing pentafluorophenyl side groups, poly(3-hexylthiophene)-b-poly(3-(6-pentafluorophenyl-hexyloxy)thiophene) (P3HT-b-P3FPHT), to boost the efficiency and stability of P3HT:PC61BM bulk-heterojunction polymer solar cells. By doping a certain amount of P3HT-b-P3FPHT, a better miscibility of P3HT with PC61BM can be acquired, forming a nanoscale bicontinuous interpenetrating network for efficient exciton dissociation. Meanwhile, the crystalline and ordered packing of P3HT chains can also be enhanced by doping P3HT-b-P3FPHT, which is benefit for efficient charge carrier transport. On this basis, the power conversion efficiency (PCE) of P3HT:PC61BM-based solar cells is improved mainly due to the increase of short circuit current density (Jsc) and fill factor (FF). More interestingly, induced by the supramolecular interaction between the pentafluorophenyl groups of P3FPHT blocks and the C60 cores of PC61BM, the severe aggregations of PC61BM molecules in the prolonged thermal annealing can be effectively suppressed, leading to the significantly improved thermal stability of the morphology and photovoltaic performance. These findings indicate that utilization of P3HT-based diblock copolymeric additives bearing pentafluorophenyl side groups is an effective and practical strategy to improve the performance and thermal stability of P3HT:PC61BM polymer solar cells.

In this work, a novel back contact interface engineering is developed for inverted planar perovskite solar cells, in which a tetrafluoroterephthalic acid (TFTPA) interlayer is inserted between CH3NH3PbI3 and PC61BM to strengthen the interface contact. Benefiting from the strong Coulombic interactions between positive electron-poor tetrafluoroterephthalate moieties and negative electron-rich fullerene molecules, as well as the coordinate effect between -COOH groups of TFTPA and Pb2+ ions of perovskites surface, a tightly jointing and defect-passivated CH3NH3PbI3/PC61BM interface is formed. The strengthened CH3NH3PbI3/PC61BM back contact can significantly facilitate electron transport and simultaneously diminish the charge accumulation and recombination. Therefore, power conversion efficiency (PCE) of the TFTPA device is up to 19.39%, whereas the hysteresis effect is weak, and the PCE is improved by 20.4% compared with the control device which does not have a TFTPA interlayer. Particularly, the moisture stability of the TFTPA device is greatly improved as compared to the control device. Our findings illustrate that the back contact interface engineering is an important and promising approach for inverted planar perovskite solar cells.

Microstructure control is critical to achieve thin film-based devices with high performance. The surface properties of the substrates on which thin films grow are expected to greatly influence the morphology and the resulting performance. Generally, homogeneous, dense and highly crystalline films are required. However, “island” like structures are usually obtained mainly due to the non-uniform nucleation. In this article, the self-assembling monolayer (SAM) strategy was applied to efficiently realize the uniform nucleation and modulate the microstructure of lead sulfide (PbS) thin films, which were fabricated on the modified ZnO-coated substrates with 3-mercaptopropionic acid (MPA) SAM via in-situ thermal decomposition of lead xanthate precursors. The results showed that PbS thin films with reduced pin-holes and uniform crystalline grains were fabricated with the incorporation of MPA SAM. More importantly, PbS thin films modulated by MPA showed better photoelectric response.

Herein, the liquid crystal molecule, 3,6-bis(5-(4-hexyl-phenyl)-2-thienyl)-2,5-bis(2-ethylhexyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DPP-TP6), is introduced into P3HT/ZnO to control the morphology of the hybrid system. Induced by the self-assembly behavior of DPP-TP6 upon thermal treatment at the mesomorphase temperature, the dispersion of ZnO nanocrystals is effectively improved and the crystallinity and ordering of the P3HT is also enhanced, which provides more interfacial area for exciton dissociation and efficient path for carrier transport. On such basis, the power conversion efficiency of P3HT/ZnO hybrid solar cells is improved mainly due to the increase of J sc .

A new photonic approach for triangular waveform generation by making full use of the polarization sensitive characteristic of the single-drive Mach–Zehnder modulator (MZM) is proposed and experimentally demonstrated. In this method, the MZM is biased at minimum transmission point and its best modulation axis has an angle with the polarization direction of injection continuous wave (CW). Due to the polarization dependent modulation efficiency of a MZM, the odd-order modulation sidebands can be generated on the parallel polarization component but only the optical carrier is presented on the orthogonal direction. After a polarizer, the required Fourier components can be projected on the same polarization direction, which contribute a triangular pulse stream by photodetection. In the experimental demonstration, triangular waveforms with repetition frequencies of 8, 10, and 12 GHz are successfully generated, respectively.

Ternary blend has been an effective strategy for achieving high efficiency in organic solar cells (OSCs). Herein, a non-fullerene small molecule acceptor (C8-DTC) was synthesized and added to the PM6: Y6 system as a third component. By adding 10% of C8-DTC as the second acceptor in the PM6:Y6 system, an impressive power conversion efficiency of 17.52% was achieved with simultaneously increased open-circuit voltage, short-circuit current-density, and fill factor. The reduced voltage loss was due to the lowered non-radiative recombination loss in comparison with the binary device. It was also found that a small amount of C8-DTC in the PM6:Y6 blend resulted in enhanced charge separation and charge transport by providing possible extra channels of hole extraction. And the ternary system formed a good phase separation and favored bi-continuous transport network, which is more conducive to balance the electron and hole transport. The results indicate that the ternary system formed by C8-DTC as the third component is an effective method to improve the performance of the PM6:Y6 based OSCs.

We propose and demonstrate a new photonic approach for triangular waveform generation. Based on an optical signal with sinusoidal envelope, an injection-locking process in a distributed-feedback semiconductor laser diode is employed to carry out the desired harmonic signal generation, and then the tailored signal is synthesized by the superimposition of these signals with proper power ratio and time delay. In this method, the conventional spectral line manipulating is transferred to individual signal envelope control, which reduces the technical requirement while the flexibility and accuracy is improved. In the experiment demonstration, triangular waveforms with the repetition frequencies of 9, 10, and 12 GHz are successfully generated. The results well agree with the theoretical predication and show great potential to realize arbitrary waveform generation.

A new photonic approach of microwave waveform generator based on time-domain synthesis is proposed and experimentally demonstrated, in which two single-drive Mach-Zehnder modulators biased at quadrature point are severed as optical pulse carvers and various microwave waveforms can be generated by carving and overlapping optical field envelopes. The theoretical analysis and simulation are developed. In experiment, a square waveform with 50% duty cycle, triangular waveform with full duty cycle, and sawtooth (or reversed-sawtooth) waveform with 50% duty cycle are generated. Furthermore, a frequency doubling sawtooth (or reversed-sawtooth) waveform with full duty cycle is also obtained.