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Copper (Cu) doped p -CdS nanoparticles have been synthesized via sol-gel method. The as-synthesized nanoparticles were successfully characterized and implemented for fabrication of Glass/ITO/ n -ZnO/ p -CdS/Al thin film photodiode. The fabricated device is tested for small (−1 V to +1 V) bias voltage. Results verified that the junction leakage current within the dark is very small. During reverse bias condition, the maximum amount of photocurrent is obtained under illumination of 100 μW/cm 2 . Electrical characterizations confirmed that the external quantum efficiency (EQE), gain and responsivity of n -ZnO/ p -CdS photodiode show improved photo response than conventional p -type materials for such a small bias voltage. It is therefore revealed that the Cu-doped CdS nanoparticles is an efficient p -type material for fabrication of thin film photo-devices. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate a novel approach to use vanadium pentaoxide (V 2 O 5 ) as a single material that can simultaneously function as both electron blocking and transport layers (EBLs and ETLs) in an organic photo-detector (OPD). Composite of V 2 O 5 and PEDOT:PSS was introduced as hole transport layer (HTL) whereas, single V 2 O 5 film was utilised as an ETL. The resultant device had the ITO/PEDOT:PSS+V 2 O 5 /PCDTBT:PC 71 BM/ V 2 O 5 /Al architecture and exhibited a new range of photo-current as well as showed an enhanced photo-response. For comparison, we also fabricated devices with ITO/PCDTBT:PC 71 BM/Al , ITO/PEDOT:PSS/PCDTBT:PC 71 BM/Al and ITO/PEDOT:PSS+V 2 O 5 /PCDTBT:PC 71 BM/Al architectures. The device with ITO/PCDTBT:PC 71 BM/Al architecture showed a photo-response in the range of ∼2.3 (OFF) to ∼6.7 mA/cm 2 (ON) which increased to almost double after the inclusion of PEDOT:PSS as an HTL and reached to ∼2.3 and ∼12.6 mA/cm 2 in OFF and ON states, respectively. In the third variant of devices with the addition of V 2 O 5 in PEDOT:PSS to form a composite HTL, the photo-response narrowed down to ∼5.4 (OFF) and ∼12.6 mA/cm 2 (ON). Lastly, the new approach with the addition of an ultrathin V 2 O 5 layer as an ETL along with composite HTL demonstrated a new range of photo-current with enhanced photo-response in the range of 13.2 mA/cm 2 (OFF) and ∼20.7 mA/cm 2 (ON). The findings of the current work suggest that addition of V 2 O 5 based ETL has tuned both photo-current and response range of the OPDs. In addition, inclusion of V 2 O 5 into the PEDOT:PSS could effectively block the electrons due to its large band-gap. [ABSTRACT FROM AUTHOR]

Inorganic-organic nanocomposites are synthesized and applied in polymer solar cells (PSCs) for improving power conversion efficiency (PEC). The hexagonal NaYbF 4 :Tb/Eu nanocrystals are synthesized, and then two organic molecules, phenanthroline (Phen) and thenoyltrifluroacetone (TTA), are introduced to modify the surface of the NaYbF 4 :Tb/Eu. As organic antennas, Phen and TTA can absorb UV and then transfer energy to inorganic nanocrystals. The prepared nanocomposites combine upconversion (UC) and downshift (DS) process under excitation, which can convert them into visible light. Thus, the inorganic-organic nanocomposites display photoresponse both in UV and NIR region. Two organic ligands and Tb 3+ play an indispensable role during the energy transfer process. The enhanced UC and tunable DS emission match well with absorption of active layer of PSC, which can enhance the performance of PSC. The open-circuit voltage (V oc ) and short-circuit current density (J sc ) of the devices are about 0.77 V and 16.48 mA cm −2 , respectively. And the PEC of PSC can be increased 7.85%, which is about 10.2% higher than that of the reference device without UC and DS. [ABSTRACT FROM AUTHOR]

Recently, transition metal chalcogenides were found to be the most promising candidates for photosensor- and photodetector-based applications. This study reports the photodetection and response properties of tin selenide (SnSe) crystals grown by the direct vapour transport (DVT) technique. The basic properties of SnSe have been reported in a previous article. Photodetection properties are investigated using polychromatic or monochromatic light of varying intensities and bias voltages. Results depict that detectors work congenially under monochromatic sources of light. It is observed that responsivity (Rλ) is higher for red, while detectivity and sensitivity are observed to be maximum for blue light under the self-biased (no bias) condition. The results observed under varying intensity (spot size) in the absence of biassing suggest that as intensity rises, all the parameters of the photodetector are also rising, while at constant intensity (30 mW/cm2), by varying the bias voltage, the detectivity of red light is decreasing due to an increment in dark current. Photodetectors are more efficient at converting optical signals to electrical signals, and their sensitivity is colour-dependent. Mainly, it is observed that monochromatic light shows high sensitivity to low bias voltages, while polychromatic light shows high sensitivity to high voltages. Observed results point to the detection of both monochromatic and polychromatic light by the fabricated detector, which can be applied to SnSe-based devices. A device can be used to fabricate colour and intensity detection. [Display omitted] • DVT grown SnSe crystals were prepared for photo detection study. • The fabricated photodetector can be used as a multicolor's photodetector in the visible range of light. • It could be used to make next-generation self-driven photo-switching diodes. • This versatile behaviour of detector can be helpful to design colour (wavelength) sensors. [ABSTRACT FROM AUTHOR]

In this article, we report on the enhanced photo-response of VO 2 (M 1) nanorods (NRs) thin film upon exposure to visible and near Infrared (NIR) light. The growth of photoconductive VO 2 (M 1) NRs thin film has been carried out using a pulsed laser deposition (PLD) technique. Field emission scanning electron microscopy (FESEM) showed the formation of NRs-like structures on the deposited thin film. The semiconductor-to-metal transition (SMT) properties at ∼64.8 °C and ∼59.8 °C during the heating and cooling cycle respectively confirm the deposition of VO 2 (M 1) thin film. The formation of VO 2 (M 1) thin film is also validated by Raman spectroscopy and X-ray diffraction (XRD) techniques. The photoconductivity of the pulsed laser deposited VO 2 (M 1) NRs thin film has been studied using the simple planar geometry upon exposure to the visible light (650 nm) and NIR light (980 nm) at 2 V and 5 V bias voltages. The estimated rise time and fall time of the photoconductive VO 2 (M 1) NRs thin films were about 1.88 ms and 1.9 ms upon exposure to the visible light and 1.89 and 2.4 ms upon exposure to the NIR light respectively. The photo-responsivity values of ∼1120 mA/W and ∼138 mA/W have been achieved for the visible and NIR light respectively at 5 V bias voltage. The photoconductive VO 2 (M 1) NRs thin film reveals highly responsive and fast visible and NIR light-sensing performance with simple planar geometry (Ag/ VO 2 (M 1) NRs thin film/Ag). • Pulsed laser deposition of VO 2 (M 1) NRs thin film. • The NRs thin film results in much improved photo-response of VO 2 (M 1) upon exposure to visible and near Infrared (NIR) light. • The photo-responsivity values of ∼1120 mA/W and ∼138 mA/W have been achieved for the visible and NIR light respectively. • The photoconduction in the VO 2 NRs thin film is based on the charge trapping mechanism mediated by the oxygen adsorption and desorption at the surface. [ABSTRACT FROM AUTHOR]

The feather-like hierarchical zinc oxide (ZnO) was synthesized via successive ionic layer adsorption and reaction without any seed layer or metal catalyst. A possible growth mechanism is proposed to explain the forming process of ZnO feather-like structures. Meanwhile, the photo-electronic performances of the feather-like ZnO have been investigated with the UV-vis-NIR spectroscopy, I-V and I-tmeasurements. The results indicate that feather-like ZnO hierarchical structures have good anti-reflection and excellent photo-sensitivity. All results suggest that the direct growth processing of novel feather-like ZnO is envisaged to have promising application in the field of photo-detector devices. [ABSTRACT FROM AUTHOR]

One of the filamentous viruses, M13 bacteriophage (phage), has attracted growing interest as a functional biopolymer assembly due to its liquid crystalline properties and designable functionalities based on genetic engineering and organic synthetic approaches. Recent studies revealed that phage could be utilized as superior building blocks for functional soft materials. By controlling the assembled states of phages by external stimuli, the potential applications of phage-based soft materials can be broadened. Herein, phages were chemically modified with azobenzene derivatives through an amidation reaction and the liquid crystalline properties of the azobenzene-modified phages were analyzed by polarized optical microscopy. It was revealed that 1600 molecules of the azobenzene derivatives were conjugated to a single phage. The liquid crystalline structure of the azobenzene-modified phage changed in response to ultraviolet light. Our findings will contribute to the construction of stimuli-responsive smart soft materials. [ABSTRACT FROM AUTHOR]

Dibutyl phthalate (DBP), as a plasticizer, has been widely used in the manufacture of plastic products. However, it is generally acknowledged that DBP is an endocrine disruptor, which would cause harm to both humans and wildlife. Generally, trace DBP in river water, soil or food is hard to be detected accurately. To solve this case, a core-shell hollow structured molecularly imprinting polymer, PH-MIPs, was synthesised via surface imprinting technology. It is noteworthy that the prepared PH-MIPs can specifically absorb and release DBP irradiated by different wavelengths of light. More importantly, the absorption capacity of PH-MIPs reaches up to 5.2 mg·g−1 without obvious attenuation in absorption performance after 4 loops of photo-controlled uptake and release of DBP. Furthermore, the PH-MIPs exhibit excellent selective absorption properties, supported by an imprinting factor of 3.4. Finally, the prepared PH-MIPs were applied to enrich and extract DBP in river water samples with the recovery rate of 83.2%. In general, the proposed PH-MIPs exhibit excellent practicability, which offers a method for the content determination of DBP as a high-efficiency solid-phase extractant for the enrichment and extraction of target pollutants. [Display omitted] • A functional photoresponsive monomer, MAPASA, was synthesised, the conformation of which can change under the light of 365 nm and 440 nm (or darkness). • Hollow-structured PH-MIPs synthesised on the surface of SiO 2 carriers with MAPASA provide assurance of photoresponsive selectivity adsorption and release of dibutyl phthalate (DBP). • To establish a photo-controllable extraction and enrichment method for determining the content of DBP. [ABSTRACT FROM AUTHOR]

Photo-responsive polymers, obtained by incorporation of photochromic azobenzene groups into polymer, can display reversible photoactuation behavior. However, the damage can cause a reduction in their service scope or service lifetime. It remains a challenge to design healable and reprocessable azobenzene-containing polymers. The polyaddition of isophorone diisocyanate (IPDI) with p -diaminoazobenzene (DAAB) and amino-terminated poly(propylene glycol) (D2000) was performed to prepare the main-chain polyurea elastomer. The hydrogen bonding between urea groups can enhance self-healing of polyurea elastomer, but its influence on photo-responsive behavior of polyurea elastomer is not clear. The proportion of ordered hydrogen bonds was regulated by changing azobenzene content and the ratio of hard/soft segments. The ordered hydrogen bonds played a fundamental role in the maximum peak intensity of polyurea, while they had no direct effect on the photo-responsive efficiency of polyurea. This study provides a feasible way to obtain healable and reprocessable azobenzene-containing polymers. • The proportion of ordered hydrogen bonds was regulated by changing azobenzene content or the ratio of hard/soft segments. • The ordered hydrogen bonds played a fundamental role in the maximum peak intensity of polyurea. • The ordered hydrogen bonds had no direct effect on the photo-responsive efficiency of polyurea. • The azobenzene-containing polyurea films possessed healable and reprocessable ability. [ABSTRACT FROM AUTHOR]

• Development of a novel CD with light-responsive oxidase-like activity. • The CD exhibits a desirable affinity to chromogenic substrate with a Km of 0.22 mM. • The determination of TOC in fruits was realized by coupling CD with chromogenic substrate. Evaluation of total antioxidant capacity (TAC) in fruits is essential for dietary guidance and health monitoring. Here, we have exploited light-response carbon dots (CDs) as oxidase-like nanozyme to determine the TAC of fruits. The CDs possess excellent oxidase-like activity with light stimulation due to the accelerated intramolecular charge transfer caused by abundant electron donating/drawing groups in precursors. The scavenger experiment reveals that the catalytic intermediate could be hydroxyl radical, which can oxidize the colorimetric substrate. With the introduction of antioxidants, the oxidization of colorimetric substrate will be alleviated due to the scavenging of this intermediate by antioxidants. Based on this, we have successfully detected three antioxidants and obtained TAC of fruits with desirable results. This work affords a rapid, cost-effective and convenient analysis tool for TAC, as well as building a strong bridge between CDs and the development of photo-responsive oxidase-like nanozymes. [ABSTRACT FROM AUTHOR]

In our previous paper, we reported that thermo-responsive emulsions can be prepared based on a long-chain amidoamine derivative (C18AA) and tetraoctylammonium bromide (TOAB), and that the C18AA + TOAB emulsions developed a characteristic interference color in a narrow temperature range. However, the coloration of the original C18AA + TOAB at room temperature exhibited poor brightness. In the present study, we show that the addition of NaOH is effective in both lowering the coloration temperature and improving the brightness of C18AA + TOAB emulsion considerably. Furthermore, we demonstrate that photo-response function can be imparted to C18AA + TOAB iridescent emulsions by introducing a photochromic naphthopyran derivative (Pyran) that reversibly changes from white to yellow upon UV irradiation. The C18AA + TOAB emulsions containing Pyran shows a dual stimuli-responsive iridescent property, and the emulsion color is controllable and reversible through both UV irradiation and temperature.

Stimuli-responsive hydrogels are a class of important materials for the preparation of flexible sensors, but the development of UV/stress dual-responsive ion-conductive hydrogels with excellent tunability for wearable devices remains a major challenge. In this study, a dual-responsive multifunctional ion-conductive hydrogel (PVA-GEL-GL-Mo 7 ) with high tensile strength, good stretchability, outstanding flexibility, and stability is successfully fabricated. The prepared hydrogel has an excellent tensile strength of 2.2 MPa, high tenacity of 5.26 MJ/m 3 , favorable extensibility (522%), and high transparency of 90%. Importantly, the hydrogels have dual responsiveness to UV light and stress, allowing it to be used as a wearable device while responding differently to the UV intensity of different outdoor environments (hydrogels can show different levels of color when exposed to different light intensities of UV light) and can remain flexible at -50 and 85 °C (sensing at both -25 and 85 °C). Therefore, the hydrogels developed in this study have good prospects in different applications, such as flexible wearable devices, duplicate paper, and dual-responsive interactive devices.

An anatase TiO2 film sensor was prepared by a facile in-situ method on the interdigitated Au electrode deposited on the alumina substrate. The structure, morphology and the optical properties of the in-situ TiO2 film sensor were characterized by X-ray diffraction, Scanning Electron Microscopy, and UV-vis diffuse reflectance spectra. The photo-assisted gas sensitivities of the prepared film towards H2 gas were evaluated at room temperature in N2 and synthetic air atmospheres. As compared to TiO2 film sensor prepared by drop-coating method, this in-situ TiO2 film sensor exhibited a more compact structure composed of uniform TiO2 microspheres as well as a better gas sensitivity towards H2 under UV irradiation, especially in synthetic air. The photo-electrochemical measurements suggest that these improvements may be associated with the efficient charge transfer in the TiO2 interface induced by the TiO2 microsphere structure. This study might offer a feasible approach to develop photo-assisted gas sensors at ambient temperature. [ABSTRACT FROM AUTHOR]

Ordered CdO nanowire branched arrays were designed and synthesized within a single hierarchical nanostructures. Such novel ordered nanowire branched arrays (ONBAs) were fabricated via one-step heating (OSH) gas-phase process and achieved the most uniform CdO nanowire branched arrays ever reported. By varying the mass ratio of CdO and Bi and adjusting the deposition position, the diameters and densities of the nanowires can be precisely controlled. A photodetector composed of CdO ONBAs demonstrated a drastic increase 867% in electrical current. In contrast, the device with a CdO thin film shows only 289% increase in current. These indicate that the CdO ONBAs are promising for photodetector applications. [ABSTRACT FROM AUTHOR]

Solid-state dye-sensitized solar cells (ssDSSC) constitute a major approach to photovoltaic energy conversion with efficiencies over 8% reported thanks to the rational design of efficient porous metal oxide electrodes, organic chromophores, and hole transporters. Among the various strategies used to push the performance ahead, doping of the nanocrystalline titanium dioxide (TiO2) electrode is regularly proposed to extend the photo-activity of the materials into the visible range. However, although various beneficial effects for device performance have been observed in the literature, they remain strongly dependent on the method used for the production of the metal oxide, and the influence of nitrogen atoms on charge kinetics remains unclear. To shed light on this open question, we synthesized a set of N-doped TiO2 nanopowders with various nitrogen contents, and exploited them for the fabrication of ssDSSC. Particularly, we carefully analyzed the localization of the dopants using X-ray photo-electron spectroscopy (XPS) and monitored their influence on the photo-induced charge kinetics probed both at the material and device levels. We demonstrate a strong correlation between the kinetics of photo-induced charge carriers probed both at the level of the nanopowders and at the level of working solar cells, illustrating a direct transposition of the photo-physic properties from materials to devices. [ABSTRACT FROM AUTHOR]

Transition metal chalcogenides (TMCs) have been extensively investigated due to their pervasive range of properties for the fabrication of several next-generation optoelectronic devices including flexible detectors, photodetectors, and photo sensors. This article reports the growth, characterization, and photodetection and response study of crystalline tin selenide (SnSe) grown by the direct vapor transport (DVT) technique. The stoichiometric confirmation of as-grown compound tin mono-selenide (SnSe) was confirmed by EDAX spectra. Structural confirmation was carried out using powder X-Ray Diffraction (PXRD). The bandgap of the grown crystals was also calculated from Tauc's plot. Anisotropic photodetection study of the SnSe photodetector demonstrates the superior photocurrent of 0.62 μA under polychromatic light for the I-II configurations of contacts. The stability of isotropic configuration is also observed to be high compared to anisotropic configuration. The results suggest isotropic contact configuration is most preferable for the SnSe photodetector. We observed that, under zero biasing conditions, the device performance improves, which indicates that the fabricated photo-diode exhibits an adequate photosensitive nature. It is observed that the device performs wisely under the self-driven condition, which points out the adequate photo-conductive (photo-self-driven) nature of the detector. [Display omitted] • As grown crystals were characterized by different techniques such as EDAX and EDAX mapping, XRD, Optical microscopy, SEM and UV-Vis. • SnSe based photodetector shows the photocurrent and responsivity of 0.62 μA and 3.01 mA/W in anisotropy (perpendicular to c-axis) configuration. • The obtain photocurrent is superior in anisotropy (perpendicular to c-axis) configuration then (parallel to c-axis) isotropy. • This work demonstrates the potential of SnSe crystal in the field of photonics as an anisotropic optoelectronic sensor. • It could be used to make next-generation self-driven photo-switching diodes, as conclusively demonstrated by the enhanced device performance shown in this paper. [ABSTRACT FROM AUTHOR]

We propose fully transparent charge-trap-type memory thin-film transistors (TFTs) with a top-gate structure composed of ZnO charge-trap and In–Ga–Zn–O active channel layers on glass substrates. Nonvolatile memory characteristics, such as a wide memory window, high-speed programming, and stable retention characteristics, were confirmed even under the illumination of red, green, blue, and white lights. The photo-stable characteristics of the proposed memory TFTs originate from the robust bias illumination stress stabilities of the employed gate-stack structure. The turn-ON voltages ( V\mathrm{\scriptscriptstyle ON} ) did not fluctuate with the variations of the bias polarity and wavelength of the illumination stresses. The maximum shift of V\mathrm{\scriptscriptstyle ON} observed was as small as −0.4 V at a negative bias stress of −20 V under a blue wavelength after 600 s. [ABSTRACT FROM PUBLISHER]

An anatase TiO2 film sensor was prepared by a facile in-situ method on the interdigitated Au electrode deposited on the alumina substrate. The structure, morphology and the optical properties of the in-situ TiO2 film sensor were characterized by X-ray diffraction, Scanning Electron Microscopy, and UV-vis diffuse reflectance spectra. The photo-assisted gas sensitivities of the prepared film towards H2 gas were evaluated at room temperature in N2 and synthetic air atmospheres. As compared to TiO2 film sensor prepared by drop-coating method, this in-situ TiO2 film sensor exhibited a more compact structure composed of uniform TiO2 microspheres as well as a better gas sensitivity towards H2 under UV irradiation, especially in synthetic air. The photo-electrochemical measurements suggest that these improvements may be associated with the efficient charge transfer in the TiO2 interface induced by the TiO2 microsphere structure. This study might offer a feasible approach to develop photo-assisted gas sensors at ambient temperature.

Solid-state dye-sensitized solar cells (ssDSSC) constitute a major approach to photovoltaic energy conversion with efficiencies over 8% reported thanks to the rational design of efficient porous metal oxide electrodes, organic chromophores, and hole transporters. Among the various strategies used to push the performance ahead, doping of the nanocrystalline titanium dioxide (TiO2) electrode is regularly proposed to extend the photo-activity of the materials into the visible range. However, although various beneficial effects for device performance have been observed in the literature, they remain strongly dependent on the method used for the production of the metal oxide, and the influence of nitrogen atoms on charge kinetics remains unclear. To shed light on this open question, we synthesized a set of N-doped TiO2 nanopowders with various nitrogen contents, and exploited them for the fabrication of ssDSSC. Particularly, we carefully analyzed the localization of the dopants using X-ray photo-electron spectroscopy (XPS) and monitored their influence on the photo-induced charge kinetics probed both at the material and device levels. We demonstrate a strong correlation between the kinetics of photo-induced charge carriers probed both at the level of the nanopowders and at the level of working solar cells, illustrating a direct transposition of the photo-physic properties from materials to devices.

Much enhanced photo-absorption of Bi 2 MoO 6 was realized by introduction of an organic dye sensitizer, copper phthalocyanine (CuPc). The CuPc/Bi 2 MoO 6 composite photocatalyst showed photo-response in the whole visible spectrum and even the near infrared region. As a result, it exhibited much higher photocatalytic activity than bare Bi 2 MoO 6 in photo-degradation of RhB and phenol under simulated solar light. Moreover, the sensitization effect of CuPc was testified by photo-degradation of RhB under a red LED (? = 620 nm)irradiation. [ABSTRACT FROM AUTHOR]

We investigated the feasibility of obtaining large photoresponse in metal-semiconductor-metal (MSM) type single nanowire device where one contact can be blocking type. We showed that suitable modification of the blocking contact by deposition of a capping metal using focused electron beam (FEB) can lead to considerable enhancement of the photoresponse. The work was done in a single Cu:TCNQ nanowire device fabricated by direct growth of nanowires (NW) from pre-patterned Cu electrode which makes the contact ohmic with the other contact made from Au. Analysis of the data shows that the large photoresponse of the devices arises predominantly due to reduction of the barriers at the Au/NW blocking contact on illumination. This is caused by the diffusion of the photo generated carriers from the nanowires to the contact region. When the barrier height is further reduced by treating the contact with FEB deposited Pt, this results in a large enhancement in the device photoresponse. [ABSTRACT FROM AUTHOR]

[Display omitted] • A self-healing hydrogel consists of PAM, PAA, and PDMAEMA. • Mo 7 endows the hydrogel with photochromic property. • Coumarin derivative endows the hydrogel with fluorescence property. • The hydrogel can be used for optical information coding and encryption. In this study, we proposed programmable photo-responsive self-healing hydrogels containing polyacrylamide (PAM), polyacrylic acid (PAA), poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMA), ammonium molybdate (Mo 7), and 7–2(acryloyl hydroxypropyl)-4-methyl-coumarin (AHPMC). Because of the electrostatic interaction of PAA and PDMAEMA, the hydrogel demonstrates good self-healing properties. Moreover, we introduced Mo 7 and coumarin derivative in the hydrogel, respectively, which endows the hydrogel photo-responsive properties. Under the control of UV light, PAM-AD/Mo 7 hydrogel with photochromic behavior could turn atrovirens, and PAM-AD/AC hydrogel with photoluminescent properties could emit blue fluorescence. In contrast, PAM-AD hydrogel possesses no photo-responsive behavior. Based on the self-healing and photo-responsive properties of the hydrogels, the three hydrogel blocks could be programmed and healed as a whole combination. In addition, we demonstrated the application of the hydrogel in optical information coding and encryption, which possesses good information coding and encryption effect. Therefore, the photo-responsive self-healing hydrogel may have potential applications in flexible information display and encryption fields. [ABSTRACT FROM AUTHOR]

Stepwise assembly starting from a preassembled metalloligand is a promising approach to obtain otherwise unattainable silver nanoclusters, but hard to be intrinsically identified due to the lack of convincing evidence to justify such a process. Herein, hexagonal and rectangular Ag18 nanoclusters are constructed from the [Mo2O5(PTC4A)2]6− (H4PTC4A=p‐phenyl‐thiacalix[4]arene) metalloligand through stepwise assembly. The formation of the metalloligand is confirmed by electrospray ionization mass spectrometry, then assembled with silver ions to form two geometrically different Ag18 nanoclusters in different solvents. The cyclization from the metalloligand to [(Mo2O5PTC4A)6]12− can be realized without alcohols and otherwise blocked by them. The installation of this metalloligand not only provides comprehensive understanding of how the solvents regulate the silver nanocluster structures, but also brings new insights for the controllable ligand metallization and subsequent condensation. [ABSTRACT FROM AUTHOR]

Stimuli-responsive supercapacitors have attracted broad interest in constructing self-powered smart devices. However, due to the demand for high cyclic stability, supercapacitors usually utilize stable or inert electrode materials, which are difficult to exhibit dynamic or stimuli-responsive behavior. Herein, this issue is addressed by designing a MoS 2 @carbon core-shell structure with ultrathin MoS 2 nanosheets incorporated in the carbon matrix. In the three-electrode system, MoS 2 @carbon delivers a specific capacitance of 1302 F g -1 at a current density of 1.0 A g -1 and shows a 90% capacitance retention after 10 000 charging-discharging cycles. The MoS 2 @carbon-based asymmetric supercapacitor displays an energy density of 75.1 Wh kg -1 at the power density of 900 W kg -1 . Because the photo-generated electrons can efficiently migrate from MoS 2 nanosheets to the carbon matrix, the assembled photo-responsive supercapacitor can answer the stimulation of ultraviolet-visible-near infrared illumination by increasing the capacitance. Particularly, under the stimulation of UV light (365 nm, 0.08 W cm -2 ), the device exhibits a ≈4.50% (≈13.9 F g -1 ) increase in capacitance after each charging-discharging cycle. The study provides a guideline for designing multi-functional supercapacitors that serve as both the energy supplier and the photo-detector., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Abstract: It is reported here that the microrod array of CdSe on indium doped tin oxide coated conducting glass (ITO) substrate has been developed by a simple electrochemical synthesis method. The electrodeposition of CdSe was also investigated by cyclic voltammetric technique. The sample was characterized by XRD, EDX, FESEM and UV–vis spectroscopic. The X-ray diffraction investigation demonstrates that the CdSe microrod is a uniform hexagonal CdSe crystal. EDX shows that the high purity CdSe is obtained. Field emission scanning electron microscope (FESEM) results show that the microrods’ length, diameter, and direction of growth are nearly uniform and perpendicular to the ITO substrate. UV–vis absorption spectrum study shows the presence of direct transition with the band gap energy 2.13eV. Photoelectrochemical solar cells are constructed using CdSe microrod array as the photocathode in polysulphide electrolyte and their power output characteristics are studied. [Copyright &y& Elsevier]

Abstract: Ni/In x Ga1 −x N/GaN Schottky barrier solar cells with different In contents (x =0.07/0.13) and two types of Schottky patterns (semitransparent current spreading layer and grid contact) are fabricated and the dependences of photovoltaic performances of these solar cells on In contents and Schottky patterns are studied. Solar cells with semitransparent contact have almost the same open-circuit voltages (V oc) as solar cells with grid contact and exhibit a higher fill factor (FF). However, solar cells with grid contact exhibit a higher maximum output power density (P max) than semitransparent contact due to their larger short-circuit current density (J sc). On the other hand, V oc and FF decrease significantly with increasing In content (beyond the decrease expected from the band gap of InGaN). By comparing the X-ray rocking curves, AFM images, dark current characteristics and spectral responsivities, it could be concluded that the deterioration of InGaN crystal quality with increasing In content is the dominant reason accounting for the strong decrease of V oc and FF. In addition, using AMPS simulation, the band structure and ideal spectral responsivities are obtained. Comparison of the experimental and simulated results also shows that high crystal quality is a key factor to obtain high performance InGaN-based Schottky barrier photovoltaic cells. [Copyright &y& Elsevier]

Abstract: We have investigated the photo-response characteristics of organic photosensors (OPS) integrated with pentacene based thin film transistors (TFTs). The fabricated device configuration is PEN/ITO/PEDOT:PSS/(poly(3-hexylethiophene)/phenyl-C61-butryic acid methyl ester) (P3HT/PCBM)/Al and PDMS/Au/(poly-4-vinyphenol) (PVP)/pentacene/Au. In order to study the effect of the applied voltage to the pentacene-TFT on the OPS, each device is connected in series. The response current is tuned dependant on the gate-source voltage and the anode-source voltage. The change of the photo induced ON current in the integrated device is measured under light illuminations ranging from 50mW/cm2 to 500mW/cm2; the corresponding photo-response (ΔI/I 0) of the devices varied from 0.16 to 1.9. We found that the photo-response characteristic is high at the low anode-source voltage and high gate-source voltage. [Copyright &y& Elsevier]

As part of a study aimed at determining the factors affecting overwintering habitat choice by Halyomorpha halys, we examined the behavioral response to light of diapausing adults (which have no reproductive activity) and non-diapausing adults. Bugs were tested individually in a choice chamber (14, 18 and 24°C) containing a dark refuge with opaque (black) sides and roof. Each bug's position in the choice chamber was recorded at regular intervals. The results indicated that diapausing bugs prefer to settle in a dark place ( p < 0.05). This preference appeared to weaken at 24°C; however, this apparent trend was probably due to the greater overall activity of the bugs under warmer conditions. In tests of non-diapausing bugs, lower proportions of the bugs were observed inside the dark refuge at higher temperatures; however, the preference for dark places was exhibited under all temperature conditions. Based on these results, we infer that H. halys adults have a fundamental preference for dark places whether or not they are in diapauses, which plays a main role in hiding behavior. This preference becomes most obvious in the winter, with the decrease in behavioral activity resulting from lower temperatures. We propose that this common preference for location is one of the factors responsible for the bugs' convergence on specific microhabitats and the overwintering aggregate formation of H. halys. [ABSTRACT FROM AUTHOR]

A reversible photo-, thermal-, and pH-responsive high-performance functional wood with fluorescence has been prepared. The properties, structure, multi-response, fluorescence, water resistance, and corrosion resistance of original wood (ORW) and functional wood (FUW) were investigated with an X-ray photoelectron spectroscopy (XPS) spectrometer, a Fourier-transform infrared (FTIR) spectrometer, a N2 adsorption–desorption analyzer, an atomic force microscope (AFM), tensile tests, a scanning electron microscope (SEM), an ultraviolet–visible (UV–Vis) spectrophotometer, a fluorescence spectrometer, the equilibrium swelling ratio (ESR), and corrosion tests. The results of XPS, FTIR, N2 adsorption–desorption, and AFM exhibited that FUW was successfully prepared. Additionally, the results of the tensile test and SEM revealed that FUW had better mechanical properties than ORW, due to the filling of epoxy resin in the pores of the wood. Moreover, the UV–Vis and fluorescence spectra demonstrated that the introduction of epoxy resin induced multi-response and fluorescence functions to FUW. Furthermore, the data of ESR and corrosion test showed that the introduction of epoxy resin greatly improved the water and corrosion resistance of wood. This study provides ideas and methods for preparing novel high-performance multi-response FUW. [ABSTRACT FROM AUTHOR]

We report an investigation on the photo-response from a GeSn-based photodetector using a tunable laser with a range of incident light power. An exponential increase in photocurrent and an exponential decay of responsivity with increase in incident optical power intensity were observed at higher optical power range. Time-resolved measurement provided evidence that indicated monomolecular and bimolecular recombination mechanisms for the photo-generated carriers for different incident optical power intensities. This investigation establishes the appropriate range of optical power intensity for GeSn-based photodetector operation. [ABSTRACT FROM AUTHOR]

Abstract: The effect of photocurrent amplification was observed in the type II isotype staggered-lineup N+-GaSb/n0-GaInAsSb single heterostructure. The illumination intensity influence to the gigantic photocurrent gain effect for applied bias voltage have been studied for this structures. A mechanism of photocurrent amplification in isotype GaSb/GaInAsSb structure due to hole confinement at the type II interface is observed, its magnitude being bias voltage and light intensity dependent. It is shown that the exponential dependence of the photocurrent on intensity confirm the photocurrent gain at small bias is due to modulation of a barrier transparency by the non-equilibrium holes trapped in the potential well in the type II interface as a previously predicted theoretically. [Copyright &y& Elsevier]

The effect of small (micromolar) amounts of chloride on photoelectrochemical properties of oxide layers spontaneously developed in Cu|Cu(II) -- glycolic acid system at pH 5.85 was investigated. Potentiometric data obtained under chopped illumination conditions show negative open-circuit photopotentials that are typical of n-type Cu2O. The level of the photopotential was found to increase with the intensity and quantum energy of disturbing illumination. The estimated band gap of n-Cu2O (∼2.2 eV) actually coincides with that obtained for crystalline p-Cu2O. Chlorides enhance formation of Cu2O, increasing the height of a characteristic current peak. Positive photocurrents were detected at moderate cathodic polarizations. The inversion of the photocurrent sign resulting in n→p transition was found to occur at a certain potential that depends on oxide layer thickness. [ABSTRACT FROM AUTHOR]

Abstract: Here, we report for the first time tubular end-capped nanofibers of CdSe on ITO substrates that have been developed using electrodeposition chemistry. We investigated the surface morphology and extended further to examine photoelectrochemical performance. As-formed ITO/CdSe/polysulphide/Pt photoelectrochemical cell showed 2% photo-conversion efficiency under 80mW/cm2 light intensity, when used in the photoelectrochemical-type cells. [Copyright &y& Elsevier]

Abstract: Most fish populations are declining worldwide and their management would benefit from a better estimation of recruitment. In glass eels, field studies suggest that estuarine migratory glass eels are sensitive enough to light to change their vertical location according to factors such as water turbidity and/or moon brightness. The response of glass eel (Anguilla anguilla L.) to light was tested in the laboratory using boxes where fish could choose between a lit and an unlit side. Responses were quantified as the proportion of glass eels remaining in the unlit chamber. Decreasing light levels were used and tested on different “age” glass eels (“age” in days since capture). In addition, measures of light at different depths of the water column were carried out in the Adour estuary (43°30′ N, 1°30′ W). The glass eel light avoidance level was lower in non-pigmented glass eel (less than 10 −10 W cm −2), than in pigmented ones (10 −9–10 −8 W cm −2). These results and field data on the measurement of light energy in the water column of Adour estuary are compared with previously published data on the estuarine migration of glass eel. [Copyright &y& Elsevier]

Abstract: ZnO-based thin film transistors (TFTs) have been fabricated on a SiO2/p-Si substrate by rf magnetron sputtering at room temperature and they exhibited a saturation current level of a few μA under a gate bias of 40V, electron mobility of less than 0.05 cm2/V s, and on/off current ratio of ∼105 in the dark. Illuminated by ultraviolet (UV, λ=340 nm) light with an optical power density of 1.26 mW/cm2, our TFT displayed a high photocurrent gain of more than 50 μA at the same gate bias of 40 V and it also showed that the photocurrent decreases with lowering the UV intensity. In a channel depletion state with a gate bias of −40 V, the photo-detecting sensitivity becomes much higher than in the accumulation state with the gate bias of 40 V. [Copyright &y& Elsevier]

The paper proposes the concept of the compact free electron laser using Smith–Purcell radiation and field emitters, and describes preliminary experiments associated with the generation of a modulation beam directly from the cathodes. The emission characteristics of the GaAs emitter designed for the Gunn effect strongly suggest the generation of a modulation beam. The illumination of a pulse laser on a p-type emitter also generates a modulation beam. However, for a high-frequency modulation beam, the suppression of the diffusion of the photogenerated carriers in the emitter is necessary. [Copyright &y& Elsevier]

Dark current–voltage characteristics, spectral response and energy diagrams have been studied for LPE grown isotype heterostructures lattice-matched to GaSb substrates. The dark current mechanisms in the isotype heterostructures were investigated at several temperatures. It is shown that a type II staggered heterojunction can behave as a Schottky diode and the dark current–voltage characteristics of this isotype heterostructures were rectifying over the whole temperature range 90–300 K. The photocurrent sign dependence on photon energy has been studied as a function of forward bias. [Copyright &y& Elsevier]

Studies on time-resolved dynamics of optically-thick YBa[sub 2]Cu[sub 3]O[sub 7-δ] microbridges biased with supercritical current pulses I of nanosecond duration and synchronously excited by femtosecond optical pulses have been carried out. The switching process is explained by the transient vortex dynamics in the superconducting stripe. It was found that the amplitude of the photoresponse increased linearly with the increase of laser fluence up to < 30 μJ/cm[sup 2] and with the increase of the bias current up to ~ 1.9I[sub c]. Calculations of quantum responsivity showed that our YBa[sub 2]Cu[sub 3]O[sub 7-δ] bridges biased with I > I[sub c] could driven by optical pulses of comparatively weak fluence in the range of few tens of mW. [ABSTRACT FROM AUTHOR]

UV irradiation (266 nm) from a nano-second pulsed laser induced a transient photo-current on Pt(1 1 1) electrode when it is contacted to an aqueous solution containing lactic acid. The potential dependence of this photo-current and the potentiodynamic behavior in the dark suggested that this electrocatalytic oxidation proceeds under the dual-path mechanism. This photo-response also revealed a potential dependence of the coverage of a short-lived adsorption intermediate. [Copyright &y& Elsevier]

Stepwise assembly starting from a preassembled metalloligand is a promising approach to obtain otherwise unattainable silver nanoclusters, but hard to be intrinsically identified due to the lack of convincing evidence to justify such a process. Herein, hexagonal and rectangular Ag 18 nanoclusters are constructed from the [Mo 2 O 5 (PTC4A) 2 ] 6- (H 4 PTC4A=p-phenyl-thiacalix[4]arene) metalloligand through stepwise assembly. The formation of the metalloligand is confirmed by electrospray ionization mass spectrometry, then assembled with silver ions to form two geometrically different Ag 18 nanoclusters in different solvents. The cyclization from the metalloligand to [(Mo 2 O 5 PTC4A) 6 ] 12- can be realized without alcohols and otherwise blocked by them. The installation of this metalloligand not only provides comprehensive understanding of how the solvents regulate the silver nanocluster structures, but also brings new insights for the controllable ligand metallization and subsequent condensation., (© 2022 Wiley-VCH GmbH.)

Dissipative or dynamic self-assembly has become one of the most important topics in the past twenty years. Under continuous energy input, the building blocks may form various dissipative structures in steady states, which will be destroyed when the energy input is stopped. Among the common forms of energy input, light is widely used for its high efficiency and adjustability. However, there is lack of study on the dissipative self-assembly of photo-responsive block copolymers under time-dependent light irradiations (especially in time-oscillatory light irradiations) as well as its design strategies. We performed non-equilibrium dissipative particle dynamics simulations of azobenzene-contained semiflexible block copolymers in melt and investigated important controlling factors that influence dissipative structures, including the volume ratio of blocks, the interaction between blocks, the oscillation period and the volume fraction of photo-responsive polymers in the system. We found that, when the oscillation period is much smaller than the diffusional timescale of block copolymer, dissipative steady structures will be formed. With the increase of oscillation period, oscillatory dissipative structures with periodic structural variation were formed based on dissipative steady structures. As oscillation period increased further, there would be no regular structure. Furthermore, the dissipative steady structures could be finely tuned by adjusting the volume fraction of photo-responsive chains in block copolymer melt. Our study provides a guidance for the design of azobenzene-contained block copolymers that can form dissipative structures in time-oscillatory irradiations and helps to predict the self-assembled morphologies. [Display omitted] • The formation of dissipative steady structures is related to the structural and diffusional properties of chain blocks. • By increasing the oscillation period properly, ordered oscillatory structures with periodic structural variation are formed. • Dissipative steady structures can be finely tuned by adjusting the volume fraction of photo-responsive chains. [ABSTRACT FROM AUTHOR]

A deep understanding of UV light response of KTaO 3 (KTO) has been explored by means of temperature dependent UV treatment. Two different temperature dependent measurement schemes have been utilized to differentiate between the shallow carriers and deep carriers. A fake transition at 220 K is found, which is actually due to the UV-induced oxygen sub-bands, resulting in the transition in photo-response from transient to persistent. Giant change in the resistance is observed for cooling as compared to heating of substrate, which is credited to the small recombination rate at low temperatures. This temperature dependent resistance response of KTaO 3 under UV light provides an importance of the measurement way of photo-charge carriers in KTaO 3. • A fake phase transition in KTaO3 is observed at high temperatures contrary to the present explored physics of KTaO3, which is resulted from the interaction of UV light with KTO. UV induced sub-bands are found to be the main cause behind such behaviour. Light induced defects are important to be explored to explore the materials for complex structures. [ABSTRACT FROM AUTHOR]