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Bis(2,2′-bipyridine)bis(isothiocyanato)ruthenium complexes are organo-metallic dyes having broad absorption properties in the visible region that are widely used in dye-sensitized opto-electronic devices. Here, we report the photocurrent measurement and stability studies of three Ru-complexes, cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II) (N3), its hydrophobic analogues cis-bis(isothiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylato)(4,4'-di-nonyl-2'-bipyridyl)ruthenium(II) (Z-907) and hydrophilic analogues (di-tetrabutylammonium cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II), (N719). Z907 shows higher stability and photoelectric conversion efficiency after 2 h analysis than its hydrophilic counter-molecules, N3 and N719. The Z907-TiO2 system exhibited a 1.09 mA/cm2 photocurrent density after 2 h of analysis, with 78% of its performance retained even after an extended 48 h of analysis. The activity of N719-TiO2 and N3-TiO2 sharply decreased after 2 h of analysis, and significant desorption of the dye present on titanium oxide was also observed. This study suggests that hydrophobicity at the electrode-dye interface is a major factor supporting the stability of the dye-sensitized photoanode. [ABSTRACT FROM AUTHOR]

A study work plan has been put up for methodical work in the field of solar energy photogalvanic (PG) cells. It was suggested and required to do experiments with PG cells in sunlight conditions. Improving the conversion of solar energy (SE) into electricity and storing it in PG cell is the goal of our study. Many characteristics of a PG cell with an MG+D-Xylose+Brij-35 system was investigated. The open circuit voltage (Voc), voltage at dark, photopotential (PP), and photocurrent (PC) recorded in this investigation are 1076.00 mV, 163.00 mV, 913.00 mV, and 673.00 μA, respectively. Through the adjustment of PG cells' numerous parameters, the effects of solar energy were investigated. Based on the aforementioned results, surfactant (Brij-35) have demonstrated through experimentation that they are an effective system and should be further investigated, particularly with regard to improving solar energy output and storage. [ABSTRACT FROM AUTHOR]

Two diphosphanes with variable-length ligands tested as nucleophiles to prepare isoporphyrin copolymers in the presence of ditolylporphyrin of zinc (ZnT2P) prevented the oxidation of the diphosphine ligand. This paper demonstrates the power of this approach and describes the photoelectrocatalytic properties. The obtained copolymers were characterized by UV–vis spectroscopy, X-ray photoelectron spectroscopy, atomic force micrograph (AFM), EQCM (Electrochemical Quartz Cristal Microbalance) and electrochemistry. Their impedance properties (EIS) were studied and their photovoltaic performances were also investigated by photocurrent transient measurements under visible light irradiation. [ABSTRACT FROM AUTHOR]

Two homoleptic terpyridyl complexes of Ru(II), 1 and Fe(II), 2 were synthesized using a ligand L1 that contained a phenyl spacer between an anthracenyl (An) and a terpyridyl (tpy) moiety. An equilibrated‐bichromophoric strategy was adopted to induce photoluminescence in 1 and 2. A glimpse into the excited state photophysical properties of 1 and 2 revealed that 1 exhibited NIR emission at ~700 nm with an excited state lifetime components of 1.33 and 6.52 ns. On the other hand, 2 was found to be non‐luminescent. The origin of emission in case of 1 was attributed to the effect of phenyl spacer which rendered the 3An state to be nearly isoenergetic to the emissive 3MLCT state of 1 facilitating 3MLCT‐3An equilibrium. This fact was supported by experimental (photocurrent generation) and theoretical (potential energy diagram) evidences. [ABSTRACT FROM AUTHOR]

To better understand the variations in physical, mechanical, and electrical properties, (Ge 2 S 8) 100-x Te x chalcogenide glasses have been synthesized. These glasses encompass a composition range of 0 ≤ x ≤ 12. The mechanical properties have been studied by determining the longitudinal (ν L) and transverse (ν T) ultrasonic velocities. A network structure evaluation with composition has been performed via parameters like coordination number (< N r >), crosslinking density (D CL), glass transition temperature (T g), etc. Also, the elastic parameters trend values have been associated with the decrease in the cohesive energy value of the system. An overall physical analysis of the Ge-S-Te systems reveals that the system's rigidity and the cross-linking density are decreasing. Within the temperature range of 300–420 K, the temperature dependency of the dark conductivity and photoconductivity has been investigated. The intensity-dependent photoconductivity is governed by a power law, with intensity (I ph = G δ ) with δ lying between 0.5 and 1. The photosensitivity values reveal that the glassy system may be suitable for applications in optoelectronic devices. A correlation among the parameters has been established by calculating elastic parameters and conductivity measurements and evaluating the network structure theoretically. The present efforts clarify the composition-structure dependence and relationship in the Ge-S-Te glass series. [ABSTRACT FROM AUTHOR]

Regioregular poly(3-hexylthiophene-2,5-diyl)-modified C60–ethylenediamine adduct microparticles film and corresponding references were fabricated using a combination of liquid/liquid interfacial precipitation and spin-coating. The photoexcitation properties of these composite films were evaluated through fluorescence spectra, which suggest that the C60–ethylenediamine adduct microparticles film enhance the fluorescence of poly(3-hexylthiophene-2,5-diyl). Larger photocurrents were observed when using the composite film of poly(3-hexylthiophene-2,5-diyl) and C60–ethylenediamine adduct microparticles film compared to those obtained using poly(3-hexylthiophene-2,5-diyl) alone. [ABSTRACT FROM AUTHOR]

This article reports an integration of organic photodetector (OPD) and organic spin valve (SV) in a single physical device — ITO/V[TCNE]2/rubrene/Co/Au magnetic OPD heterostructure. Generation of photocurrent with more than 43.3% photocurrent‐to‐dark current ratio is revealed in this device under illumination of 660 nm red laser light at 0.4 V electrical bias. Moreover, room temperature SV response with up to 7.7% SV magnetoresistance peak is found at 138 Oe in the same heterostructure. Such intriguing coexistence of photocurrent generation and SV effect at room temperature in a single magnetic OPD heterostructure paves the way for the development of eco‐friendly all‐organic next‐generation multifunctional opto‐spintronics devices. [ABSTRACT FROM AUTHOR]

Natural photosynthesis holds great potential to generate clean electricity from solar energy. In order to utilize this process for power generation, it is necessary to rewire photosynthetic electron transport chains (PETCs) of living photosynthetic organisms to redirect more electron flux toward an extracellular electrode. In this study, a semi‐artificial rewiring strategy, which use a water‐soluble fullerene derivative to capture electrons from PETCs and donate them for electrical current generation, is proposed. A positively charged fullerene derivative, functionalized with N,N‐dimethyl pyrrolidinium iodide, is found to be efficiently taken up by the cyanobacterium Synechocystis sp. PCC 6803. The distribution of this fullerene derivative near the thylakoid membrane, as well as site‐specific inhibitor assays and transient absorption spectroscopy, suggest that it can directly interact with the redox centers in the PETCs, particularly the acceptor side of photosystem I (PSI). The internalized fullerene derivatives facilitate the extraction of photosynthetic electrons and significantly enhance the photocurrent density of Synechocystis by approximately tenfold. This work opens up new possibility for the application of fullerenes as an excellent 3D electron carrier in living biophotovoltaics. [ABSTRACT FROM AUTHOR]

Silver(I) oxide is considered as one of the promising materials for photoelectrochemical technologies because it has an optimal band gap, relatively low cost, and a wide variety of production methods. However, its characteristics such as quantum efficiency, morphology, and crystal structure parameters require optimization, which can be achieved by applying the most suitable method for the obtaining of the material. One of the fairly simple methods is the anodic oxidation of silver or its alloys in alkaline media, which allows obtaining oxide phases with a controlled composition and predictable properties by varying the concentration of the alloy components and electrolysis mode. The purpose of this work is to reveal the features of anodic formation and to determine the photoelectrochemical characteristics of silver(I) oxide on silver–palladium alloys in deaerated 0.1 M KOH solution. The regularities of the anodic formation of Ag(I) oxide on alloys of the Ag–Pd-system with the palladium atomic fraction from 0.05 to 0.20 in deaerated 0.1 M KOH solution were studied by non-stationary electrochemical methods of cyclic voltammetry, chronoamperometry with synchronous recording of photocurrent, and photopotential measurements. The phase composition of the alloys (alpha phase) was determined from the results of X-ray diffractometry. Chemical composition was determined by energy dispersive microanalysis. Photoelectrochemical parameters were calculated from the results of the photocurrent and photopotential measurements. It was established that the Ag(I) oxide anodically formed on silver–palladium alloys is characterized by n-type conductivity and the predominance of donor defects. On the alloys with a relatively low palladium concentration (5 and 10 at %), Ag(I) oxide with a higher concentration of defects is formed, while on alloys with a relatively high palladium concentration (15 and 20 at %), with a lower concentration of defects than on pure silver. [ABSTRACT FROM AUTHOR]

As a typical organic semiconductor material, rubrene plays a prominent role in the field of optoelectronic devices. Here, a notable photoluminescence (PL) and photocurrent enhancement of rubrene by 8‐ and 2.5‐fold is reported under compression, respectively. The shortening of the π−π stacking distance and the twisting of the lateral phenyl are crucial reasons for the decrease in the bandgap, resulting in the enhancement of PL emission and photocurrent. Pressure can effectively suppress the excitons transition from a free exciton state to a self‐trapped exciton state and improve the emission efficiency. The photocurrent is subject to dual regulation by bandgap and resistance. Interestingly, rubrene undergoes an electronic structure transition at about 4.8 GPa, which is responsible for the weakening of PL emission and photocurrent. This work provides a strategy for optimizing the performance of rubrene‐based optoelectronic devices and designing novel optoelectronic materials. [ABSTRACT FROM AUTHOR]

In this study, the photoelectric properties of a complete series of GaS1−xSex (0 ≤ x ≤ 1) layered crystals are investigated. The photoconductivity spectra indicate a decreasing bandgap of GaS1−xSex as the Se composition x increases. Time-resolved photocurrent measurements reveal a significant improvement in the response of GaS1−xSex to light with increasing x. Frequency-dependent photocurrent measurements demonstrate that both pure GaS crystals and GaS1−xSex ternary alloy crystals exhibit a rapid decrease in photocurrents with increasing illumination frequency. Crystals with lower x exhibit a faster decrease in photocurrent. However, pure GaSe crystal maintains its photocurrent significantly even at high frequencies. Measurements for laser-power-dependent photoresponsivity and bias-voltage-dependent photoresponsivity also indicate an increase in the photoresponsivity of GaS1−xSex as x increases. Overall, the photoresponsive performance of GaS1−xSex is enhanced with increasing x, and pure GaSe exhibits the best performance. This result contradicts the findings of previous reports. Additionally, the inverse trends between bandgap and photoresponsivity with increasing x suggest that GaS1−xSex-based photodetectors could potentially offer a high response and wavelength-selectivity for UV and visible light detection. Thus, this work provides novel insights into the photoelectric characteristics of GaS1−xSex layered crystals and highlights their potential for optoelectronic applications. [ABSTRACT FROM AUTHOR]

The photogalvanic effect (PGE) can produce a photocurrent independent of a p–n junction or bias voltage, but the resulting photocurrent is usually very small. An appropriate lateral heterojunction can effectively enhance PGE. Here, we studied the PGE of a monolayer (ML) Janus MoSSe-CrSSe lateral heterojunction through ab initio quantum transport simulation. Compared with that of a homogeneous material, PGE is enhanced due to the reduced symmetry of the lateral heterojunction, and the maximum increase ratio in the photocurrent is more than two orders of magnitude greater than that of the homogeneous ML MoSSe and CrSSe photodetectors. A peak maximum photocurrent of 13.85 a02/photon and high polarization sensitivity with a maximum extinction ratio of 308 are obtained for the ML MoSSe-CrSSe lateral heterojunction. These favorable properties indicate that the MoSSe-CrSSe lateral heterojunction is a promising candidate for photodetectors. [ABSTRACT FROM AUTHOR]

Investigation of carbon nanotubes is a modern trend due to their combination of unique physical, chemical, electrical, and optical properties. Carboxyl-functionalized carbon nanotubes (fCNTs) for investigation of photoelectrical properties were synthesized. The photo-sensitivity spectra of a carboxyl-functionalized CNT sample for voltage range from 1 to 9 V, and for the spectral range from 400 to 900 nm were investigated. The voltage equal to 1 V generated lower photosensitivity in the broadband wavelength range for visible to near-infrared. The most efficient photocurrents of fCNTs were received for a voltage of 5 V in the wavelength range λp~400-800 nm and for voltage U=3V in the broadband spectral range λp~400-900 nm. The experimental data analysis helped to determine the widest photosensitivity range, as well as the highest sensitivity value. As result, the voltage U=5V was obtained. Here, the most significant photocurrent peak with Ip~2.67 μA for wavelength λ~720 nm was observed. A comparison between the photosensitivity spectra of fCNTs and pure CNTs shows that the photosensitivity of fCNTs has increased significantly. Thus, the maximum photosensitivity for fCNTs is Ip ~ 2.67 μA, and for pure CNTs, it equals Ip ~ 0.185 μA. A 14-fold enhancement of photosensitivity for fCNT has been registered. The mathematical analysis of spectral dependencies of generated photocurrents under different applied voltages can be described using fourth-order polynomials. The I-V characteristics for wavelengths 760 nm and 780 nm have the same trend with the shift of photocurrent maximum to the lower parameters of voltage. The carboxyl-functionalized nanotubes can be effectively used as light detectors and in optoelectronic applications. [ABSTRACT FROM AUTHOR]

TNAs have been synthesized using a two-step anodization method by increasing the second-step voltages. The titanium (Ti) foil was used as the anode, and the first step of anodization layer was removed by sonication in the deionized water. The second anodization step was conducted using the same electrolyte but at a higher potential. The modification of the second-step voltage was discussed with correlation for the morphology and photoelectrochemical performance of TNAs. Increasing the second voltage of two-step anodization leads to a decrease in the bandgap of the anatase phase of TNAs at 3.09 eV. The highly ordered TNAs were formed by increasing the second-step voltage based on the Fast Fourier Transform (FFT) images with a higher regularity ratio (RR) with 30 V for 30 min in the first step and 40 V for 30 min in the second step. The tube length of TNAs was produced in a short time of anodization. The photocurrent density of TNAs prepared by increasing voltage in the second step is higher than that of the one-step anodization. [ABSTRACT FROM AUTHOR]

In this work, we have investigated n-ZnO/p-porous GaAs/p++-GaAs heterostructure for low-cost photodetector applications. Solution-based deposition process was used to synthesize ZnO thin film on porous GaAs layer formed by anodic etching. Energy dispersive x-ray spectroscopy (EDX) was used for chemical characterization and revealed that the deposited ZnO film was oxygen rich. Scanning electron microscopy (SEM) analysis demonstrated a porous surface morphology of the ZnO film and the infiltration of a part of the deposited film inside the porous GaAs matrix. The transport mechanisms of the n-ZnO/p-porous_GaAs/p++-GaAs heterostructure were investigated via current–voltage (I–V) measurements in the dark at room temperature. I–V characteristic showed rectification behavior, and the maximum value of the rectification ratio is 53 at ± 1.78 V. A series resistance Rs = 15 Ω and an ideality factor, n = 8, were obtained by using the Cheung function. The Forward I–V curve in Log–Log scales follows a power law dependence characteristic of trap-assisted space charge limited conduction. In the reverse bias voltages, we found that the thermionic emission theory in the presence of an interface layer reproduces the current–voltage characteristic. A potential barrier height of φ B = 580 meV and an ideality factor n = 1.06 were obtained. For more investigations, we carried out impedance spectroscopy measurements. From the Cole–Cole impedance curves of the reverse-biased device, we demonstrated the formation of two depletion regions operating in opposite directions to the applied voltage. Conductance-frequency (G-f) experimental results agree with Jonsher's law, proving that charge transport processes across device interfaces occur by jumping between localized states. The analysis of I–V characteristic under illumination demonstrates that the n-ZnO/p-porous GaAs/p++-GaAs device can be used for photodetection applications. The measured photocurrent reaches a value of 39 mA for an applied voltage of 1.48 V. The photocurrent spectrum showed a signal without applied voltage and confirmed the presence of an internal electric field that self-polarizes the device. [ABSTRACT FROM AUTHOR]

Absorption of the below-bandgap solar radiation and direct pre-thermalizational impact of a hot carrier (HC) on the operation of a single-junction solar cell are ignored by the Shockley-Queisser theory. The detrimental effect of the HC is generally accepted only via the thermalization-caused heating of the lattice. Here, the authors demonstrate experimental evidence of the HC photocurrent induced by the below-bandgap 0.92 eV photon energy radiation in an industrial silicon solar cell. The carriers are heated both through direct freecarrier absorption and by residual photon energy remaining after the electron-hole pair generation. The polarity of the HC photocurrent opposes that of the conventional generation photocurrent, indicating that the total current across the p-n junction is contingent upon the interplay between these two currents. A model of current-voltage characteristics analysis allowing us to obtain a reasonable value of the HC temperature was also proposed. This work is remarkable in two ways: first, it contributes to an understanding of HC phenomena in photovoltaic devices, and second, it prompts discussion of the HC photocurrent as a new intrinsic loss mechanism in solar cells. [ABSTRACT FROM AUTHOR]

In the recent research we compared the solar energy performance of photogalvanic cell (PG cell) for two food dyes that act as photosensitizer tatrazine and sunset yellow in the DSS-EDTA (Dioctyl sodium sulphosuccinate-Ethylenediamine tetraacetic acid) system for power generation and its storage. Both are azo food dyes and act as photosensitizer, DSS acts as an anionic Surfactant and EDTA act as a reductant. The electrical parameters of both dye systems were studied and compared. The observed conversion efficiencies and fill factor for both systems in the DSS-EDTA system were 0.6163%, 0.2800, and 1.2186%, 0.2900, respectively. The stable photopotential (Voc) was 879 mV and 864.0 mV whereas the stable photocurrent (isc) was 220 µA and 390 µA, respectively. In addition to having built-in storage capacity, the photogalvanic cell can operate in dark conditions. The amount of time required for the cell to reach half the value of power at power point, which was measure its performance called t1/2 of the cell. Cell performance of both PG cell was determined and for the Tartrazine-EDTA-DSS system it has been obtained 100 min while for the sunset yellow-EDTA-DSS system it was observed at 140 minutes. The current-voltage (i-v) characteristics of both the systems have been studied. [ABSTRACT FROM AUTHOR]

Abstract MXenes, a class of two-dimensional (2D) transition metal carbides and nitrides, have a wide range of potential applications due to their unique electronic, optical, plasmonic, and other properties. SnO2–Ti3C2 MXene with different contents of Ti3C2 (0.5, 1.0, 2.0, 2.5 wt‰), experimentally, has been used as electron transport layers (ETLs) in Perovskite Solar Cells (PSCs). The SCAPS-1D simulation software could simulate a perovskite solar cell comprised of CH3NH3PbI3 absorber and SnO2 (or SnO2–Ti3C2) ETL. The simulation results like Power Conversion Efficiency (PCE), Open circuit voltage (VOC), Short circuit current density (JSC), Fill Factor (FF), and External Quantum Efficiency (EQE) have been compared within samples with different weight percentages of Ti3C2 MXene incorporated in ETL. Reportedly, the ETL of SnO2 with Ti3C2 (1.0 wt‰) effectively increases PCE from 17.32 to 18.32%. We simulate the role of MXene in changing the ideality factor (nid), photocurrent (JPh), built-in potential (Vbi), and recombination resistance (Rrec). The study of interface recombination currents and electric field shows that cells with 1.0 wt‰ of MXene in SnO2 ETL have higher values of ideality factor, built-in potential, and recombination resistance. The correlation between these values and cell performance allows one to conclude the best cell performance for the sample with 1.0 wt‰ of MXene in SnO2 ETL. With an optimization procedure for this cell, an efficiency of 27.81% is reachable.

This study reports on the deposition of highly transparent conducting n-type zinc oxide (ZnO) thin films on FTO substrates, via an optimized doping process. Our work is focused on doping zinc oxide with vanadium (V) using spray pyrolysis technique and ensure the synthesis of nanoparticles-shaped ZnO, with an improved optical, microstructural and electrical properties for solar cells applications, as optical window material. Undoped and V-doped ZnO thin films, with careful optimized amounts (2, 4, 6 and 8 at.%), were grown at maintained 550∘C pre-heated substrate during the deposition process, which enables us to obtain nano-sized ZnO particles. We proved that 4 at.% is the optimum V content that enhances the crystallinity of the grown thin film noticeably. With an average transmittance of 80%, the deposited thin films revealed high transparency in the visible domain with a slight decrease in optical transmission which might result from additional scattering. UV-Visible analysis showed that increasing V amounts, a resulting decrease in the energy bandgap ( E g ) is obtained from 3.26 eV to 3.17 eV for 4 at.% of V content. Moreover, deep level defects in zinc oxide can be reduced with vanadium doping and consequently strengthen the UV emission. The UV emission peak intensity rises with increasing V-doping amount then decreases slightly at 8% of V content. The electrical properties measurements showed a decrease in resistivity from 2.8 10 − 2 Ω ⋅ cm to 0.9 10 − 2 Ω ⋅ cm when doping with 4 at.% of V. The crucial effect of the V-doping of ZnO was also demonstrated via the enhancement of carrier mobility that attains 38.5 cm2/V ⋅ s at the optimum vanadium content. The photocurrent analysis revealed much higher visible light absorption in the V-doped zinc oxide thin films than that of undoped film. The photocatalytic activity enhancements are attributed to the lower recombination rate of the photogenerated electron-hole pairs, the narrowed bandgap, yielding a higher photocatalytic performance. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are porous organic materials with well‐defined and uniform structure. The material is an excellent candidate as a solid adsorbent for iodine adsorption. In the present study, we report the synthesis of COF with porphyrin moiety, TF‐TA‐COF, by solvothermal reaction, which was characterized by XRD, solid‐state 13C NMR, IR, TGA, and nitrogen adsorption‐desorption analysis. TF‐TA‐COF showed a high specific surface area of 443 m2 g−1, and exhibited good adsorption performance for iodine vapor, with an adsorption capacity of 2.74 g g−1. XPS and Raman spectrum indicated that a hybrid of physisorption and chemisorption took place between host COF and iodine molecules. The electric properties of iodine‐loaded TF‐TA‐COF were also studied. After doped with iodine, the conductivity of the material increased by more than 5 orders of magnitude. The photoconductivity of I2‐doped COF was also studied and TF‐TA‐COF showed doping‐enhanced photocurrent generation. [ABSTRACT FROM AUTHOR]

Tin‐based perovskite solar cells (TPSCs) have attracted significant research interest due to their exceptional optoelectronic properties and environmentally friendly characteristics. However, TPSCs with ideal bandgap suffer from substantial current losses, necessitating the development of innovative interface engineering strategies to enhance device performance. In this study, an unprecedented approach constructing charge transfer path is presented by a simple post‐growth treatment of 3‐Aminomethylbenzo[b]thiophene (3‐AMBTh) on the perovskite film. The selective reaction of 3‐AMBTh with exposed FA+ on the perovskite surface suppresses the formation of iodine vacancy defects, leading to a reduction in trap density. Additionally, the residual aromatic rings on the surface form an effective π–π stacking interaction system with subsequently deposited ICBA, facilitating enhanced charge transfer at the interface. By harnessing the potential of the charge transfer path, the TPSCs exhibit remarkable device efficiency of up to 14.53%, positioning them among the top‐performing TPSCs reported to date. [ABSTRACT FROM AUTHOR]

This work explores the use of air as a reactive gas in the sputtering deposition of N-doped TiO 2 -based bilayer, gradient, and multilayer thin films for photoelectrochemical evaluations. By merely adjusting the air/Ar flow ratio, crystalline phases, nitrogen doping contents, electrical properties, optical bandgaps, and valence band maximum (VBM) positions of N–TiO 2 films were tailored. The N–TiO 2 /TiN(O) bilayer on the glass substrates exhibited a peak photocurrent density of 776 μA cm−2 at an air/Ar ratio of 1.60, which may be due to suitable bandgap and carrier mobility of the TiO 2 overlayer as the bandgap was affected by the nitrogen content and rutile fraction in the TiO 2 overlayer. To further improve the performance of N–TiO 2 , stepwise and sequential gradient structures with gradient bandgaps and nitrogen contents were produced, which could reach photocurrent densities of 805 ± 4 and 837 ± 3 μA cm−2, respectively. The gradient structures lead to enhanced light absorption efficiency and reduce carrier recombination. The N–TiO 2 /TiN(O) multilayer structures were also designed and revealed the highest photocurrent density of 865 ± 7 μA cm−2. Such evident enhancement is mainly due to the thin conductive while translucent TiN(O) layers between the photoelectrochemical-active N–TiO 2 layers provide multiple low-impedance channels in enhancing carrier transport. [Display omitted] • N–TiO 2 -based bilayer, gradient, and multilayer films were made by air sputtering. • Enhancements of photocurrents were achieved via gradient and multilayer designs. • N–TiO 2 gradient films with N-gradients were produced by varying air/Ar ratios. • Multiple thin translucent TiN(O) films provide low-impedance paths in the multilayer. • Obtained highest photocurrent density was 865 ± 7 μA cm−2. [ABSTRACT FROM AUTHOR]

The emerging flexible device technologies have fascinated the modern optoelectronic industry owing to their invincible properties such as wearable, stretchable, smart, energy‐efficient, scalability, cost‐effective, and high performance. However, there is still room for improvements such as performance, reliability, and mass production. This research work fabricates laser‐induced graphene (LIG) interdigitated electrodes based on flexible UV photodetectors over polyimide substrate, using solution‐processed tungsten oxide (WO3) thin film as photoactive material. The best device performance is achieved through the optimization of laser power for the deposition of LIG, as well as a different solvent for WO3. The device shows excellent photoresponsivity, external quantum efficiency, and specific detectivity of 500 mA W−1, 164%, and 3.09 × 1012 Jones, respectively. Moreover, a fast response time, such as 0.3 ms for 375 nm light, is observed. This study offers a comprehensive elucidation of the intricate process through which photoelectrons are moved toward WO3 facilitated by the electric field present at the interface of the LIG and WO3. [ABSTRACT FROM AUTHOR]

This paper reports a multifunctional magnetic‐photoelectric laminate device based on the integration of spintronic material (La0.7Sr0.3MnO3) and multiferroic (Ni‐doped BiFeO3), in which the repeatable modulation effect on the photoelectric properties were achieved by applying external magnetic fields. More obviously, photocurrent density (J) of the laminate was largely enhanced, the change rate of J up to 287.6% is obtained. This sensing function effect should be attributed to the low‐field magnetoresistance effect in perovskite manganite and the scattering of spin photoelectron in multiferroic material. The laminate perfectly combines the functions of sensor and controller, which can not only reflect the intensity of environmental magnetic field, but also modulate the photoelectric conversion performance. This work provides an alternative and facile way to realize multi‐degree‐of‐freedom control for photoelectric conversion performances and lastly miniaturize multifunction device. The photoelectron transport process in BiFe0.9Ni0.1O3/La0.7Sr0.3MnO3 laminate thin film under external magnetic field. Here we reported on a magnetic‐photocurrent effect, which provides an optional way to manipulate photoelectric conversion properties in multiferroic thin films. [ABSTRACT FROM AUTHOR]

It is now widely accepted that certain effects arising from localised surface plasmon resonance, such as enhanced electromagnetic fields, hot carriers, and thermal effects, can facilitate electrocatalytic processes. This newly emerging field of research is commonly referred to as plasmon‐enhanced electrocatalysis (PEEC) and is attracting increasing interest from the research community, particularly regarding harnessing the high energy of hot carriers. However, this has led to a lack of critical analysis in the literature, where the participation of hot carriers is routinely claimed due to their perceived desirability, while the contribution of other effects is often not sufficiently investigated. As a result, correctly differentiating between the possible mechanisms at play has become a key point of contention. In this review, we specifically focus on the mechanisms behind photocurrents observed in PEEC and critically evaluate the possibility of alternative sources of current enhancement in the reported PEEC systems. Furthermore, we present guidelines for the best experimental practices and methods to distinguish between the various enhancement mechanisms in PEEC. [ABSTRACT FROM AUTHOR]

In this paper, a theoretical model has been presented to calculate the photocurrent and detectivity in a TiO2/ZnS core‐shell quantum dot (CSQD) photodetector. Analytical modeling permits to calculate the available photocurrent and corresponding detectivity from the CSQD structures. In this theoretical model, the subband energy levels of the CSQD are estimated using the 3D symmetric quantum box structures with a finite potential barrier. The finite band offset determines the number of available subband energy levels in the CSQD structures depending on the size of the core. Theoretical results show the variation of photocurrent and corresponding detectivity with different core sizes of the CSQD for a constant shell thickness. The calculations indicate that for electronic intersubband transitions detectivity is higher compared with the hole transitions. [ABSTRACT FROM AUTHOR]

Low efficiency of Terahertz (THz) radiation and radiation power have limited the development of THz Science and Technology. Thus, with the aims of achieving greater photoconductive current and improving radiation characteristics of THz photoconductive antenna (PCA), this study utilized Extraordinary Optical Transmission (EOT) of light passing through various subwavelength metal structures to control and restrain the light wave in subwavelength scale. Furthermore, by grooving the grating electrode structure, the influence of metal grating's EOT on the transmission field of PCA were investigated and analyzed. Simulation results show that the effect of local electric field enhancement is significant. When the incident power is 0.1 W, the peak value of the local electric field reaches 7. 0 4 × 1 0 7 V/m. In addition, comparing to the grating electrode with no groove structure in which the field intensity was less than 4. 2 8 × 1 0 6 V/m, the local electric field increased by 16.4 times, respectively. Correspondingly, the photocurrent intensity of the improved photoconductive plasmonic structure is increased by 72.3 times. In conclusion, the improved plasma photoconductive structure was shown to obviously enhance the transmission field strength of semiconductor materials and the current of the PCA, and accordingly, to improve the THz radiation capability. [ABSTRACT FROM AUTHOR]

In this work, we consider the results of studying the spectral distribution, the temperature dependence of photoconductivity, and the dependence of the spectral distribution of photoconductivity on the applied electric field of doped with rare earth elements GaTe single crystals in the temperature range of 30–300 K. As the temperature decreases to 30 K, the impurity peaks disappear, and the intense maximum shifts to the short wavelength region. The increase in impurity photoconductivity with increasing temperature is due to the thermooptical filling of acceptor levels with electrons and their further transition to the conduction band under the action of illumination. Such a temperature dependence of the photoconductivity is explained by the presence of acceptor levels in the band gap. [ABSTRACT FROM AUTHOR]

This study examines In2S3 concentration to the photo‐induced current density of particulate In2O3–In2S3 composite heterostructures under visible light irradiation. A self‐templated approach involving hydrothermal sulfidation of In2O3 nanofibers with thioacetamide (TAA) in water produces the In2O3–In2S3 core–shell structure at a moderate temperature. The In2S3 fraction is readily tunable by adjusting the TAA concentration. Incorporating In2S3 (45–82 wt.%) leads to a decreased bandgap from 3.1 to ca. 2.3 eV, enabling the harvest of partial visible‐light energy to create charged carriers efficiently. The photocurrent is particularly pronounced when the In2O3–In2S3 composites consist of 45 wt.% In2S3, to which the photocurrent intensity is more significant than 0.1 mA⋅cm−2 at 0.8 V in 0.1 M Na2SO4 solution compared to less than 0.01 mA⋅cm−2 for the rest of the In2O3–In2S3 counterparts. This is attributable to the enhanced electron–hole separation at the semiconducting heterojunction and the more efficient use of the light spectrum due to the narrowing bandgap. [ABSTRACT FROM AUTHOR]

In photovoltaics, hot carriers are mainly considered as a workforce for efficient hot carrier solar cells or as a reason of unfavorable heating of classical solar cells. Here we present experimental evidence of the hot carrier photocurrent, i.e., the current induced across a p-n junction by the hot carriers before their thermalisation. Competition between two photocurrents, the hot carrier and the generation-caused, is highlighted through excitation intensity, wavelength, sample temperature and bias voltage. The adverse impact of the hot carrier effect on the successful operation of a single junction solar cell is demonstrated, suggesting the need to discuss it as a novel form of intrinsic loss mechanism. [ABSTRACT FROM AUTHOR]

Abstract Natural photosynthesis holds great potential to generate clean electricity from solar energy. In order to utilize this process for power generation, it is necessary to rewire photosynthetic electron transport chains (PETCs) of living photosynthetic organisms to redirect more electron flux toward an extracellular electrode. In this study, a semi‐artificial rewiring strategy, which use a water‐soluble fullerene derivative to capture electrons from PETCs and donate them for electrical current generation, is proposed. A positively charged fullerene derivative, functionalized with N,N‐dimethyl pyrrolidinium iodide, is found to be efficiently taken up by the cyanobacterium Synechocystis sp. PCC 6803. The distribution of this fullerene derivative near the thylakoid membrane, as well as site‐specific inhibitor assays and transient absorption spectroscopy, suggest that it can directly interact with the redox centers in the PETCs, particularly the acceptor side of photosystem I (PSI). The internalized fullerene derivatives facilitate the extraction of photosynthetic electrons and significantly enhance the photocurrent density of Synechocystis by approximately tenfold. This work opens up new possibility for the application of fullerenes as an excellent 3D electron carrier in living biophotovoltaics.

Recently, a new photoelectric phenomenon dubbed in-plane photoelectric (IPPE) effect has been demonstrated experimentally. In this work, we investigate the IPPE effect in a zigzag-edged or armchair-edged phosphorene nanoribbons (ZPNRs or APNRs) that is modulated by a step barrier. Based on the Floquet theory, we calculate the directed photocurrent Ī|| (Ī⊥) generated by a non-resonant linearly-polarized light with polarization vector in parallel with (perpendicular to) the nanoribbon direction. We find that such a photocurrent depends on the edge type of the nanoribbon and the polarization direction of light. At high Fermi energies, the IPPE current Ī|| in APNRs is significantly stronger than that in ZPNRs under the same conditions. In APNRs, both Ī|| and Ī⊥ always have the same direction and |Ī||:Ī⊥|>10. In contrast, in ZPNRs Ī⊥ can reverse its direction (becoming negative) and is comparable to Ī|| in amplitude. The negative photocurrent arises from both the photon-emission and photon-absorption process related to the quasi-flat-band in ZPNRs. This indicates that the mid-gap states can be detected by the IPPE effect. The energy scope and amplitude of negative photocurrent can be tuned by adjusting the height of the step barrier, the light frequency, and the light intensity.

Aversive responses to bright light (photoaversion) require signaling from the eye to the brain. Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) encode absolute light intensity and are thought to provide the light signals for photoaversion. Consistent with this, neonatal mice exhibit photoaversion before the developmental onset of image vision, and melanopsin deletion abolishes photoaversion in neonates. It is not well understood how the population of ipRGCs, which constitutes multiple physiologically distinct types (denoted M1-M6 in mouse), encodes light stimuli to produce an aversive response. Here, we provide several lines of evidence that M1 ipRGCs that lack the Brn3b transcription factor drive photoaversion in neonatal mice. First, neonatal mice lacking TRPC6 and TRPC7 ion channels failed to turn away from bright light, while two photon Ca2+ imaging of their acutely isolated retinas revealed reduced photosensitivity in M1 ipRGCs, but not other ipRGC types. Second, mice in which all ipRGC types except for Brn3b-negative M1 ipRGCs are ablated exhibited normal photoaversion. Third, pharmacological blockade or genetic knockout of gap junction channels expressed by ipRGCs, which reduces the light sensitivity of M2-M6 ipRGCs in the neonatal retina, had small effects on photoaversion only at the brightest light intensities. Finally, M1s were not strongly depolarized by spontaneous retinal waves, a robust source of activity in the developing retina that depolarizes all other ipRGC types. M1s therefore constitute a separate information channel between the neonatal retina and brain that could ensure behavioral responses to light but not spontaneous retinal waves.SIGNIFICANCE STATEMENT At an early stage of development, before the maturation of photoreceptor input to the retina, neonatal mice exhibit photoaversion. On exposure to bright light, they turn away and emit ultrasonic vocalizations, a cue to their parents to return them to the nest. Neonatal photoaversion is mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs), a small percentage of the retinal ganglion cell population that express the photopigment melanopsin and depolarize directly in response to light. This study shows that photoaversion is mediated by a subset of ipRGCs, called M1-ipRGCs. Moreover, M1-ipRGCs have reduced responses to retinal waves, providing a mechanism by which the mouse distinguishes light stimulation from developmental patterns of spontaneous activity.

MIS structures with a nonstoichiometric oxide dielectric and a transparent top electrode are attracting attention for use as low-cost Schottky-diode-based solar cells, photodetectors, and photomemristors. Previously, attempts were made to use both thin tunnel layers of silicon oxide or rather thick silicon-rich oxides for these purposes. This work is the first attempt to use films of nonstoichiometric germanosilicate films in photosensitive MIS structures. [ABSTRACT FROM AUTHOR]

Recently, nano‐optics have attracted immense interest among researchers for the design of all‐optical devices to fulfill the ongoing demands of sustainable energy. Plasmonics of nanoscale materials can be employed to manipulate, guide, and convert ambient electromagnetic radiation to elevate the present state‐of‐the‐art in energy technology. To meet the clean energy challenges that lie ahead, it is indispensable to imbue preconceived notions of the electromagnetic configurations emerging from a set of physical observables that define the plasmonic states of the nanosystem. In this work, a set of hypothetical two‐dimensional plasmonic lattices formed with periodically interdigitated gold nanorods having different geometries and orientations is used as a top layer to simulate the carrier densities of field effect transistors (FETs) as a function of their near‐field potentials within the limit of classical electromagnetism. Based on these considerations, theoretically, a set of principles for the strategic design of different symmetric motifs is illustrated that can increase the effective path length of carriers through strong electromagnetic field confinement to achieve the desired enhancement of the photocurrent of a FET. In essence, the work demonstrates a protocol to design a plasmonic top layer for the maximization of gain voltage of an FET by manipulating the on‐chip local field through plasmonic coupling, giving a new pathway to designing plasmonic FETs. [ABSTRACT FROM AUTHOR]

The structure and electrical and optoelectronic properties of nanostructured carbon films obtained by methane plasma deposition with subsequent annealing have been studied. It is shown that the film formation conditions affect the final physicochemical parameters. The film morphology has been investigated by atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray energy-dispersive analysis, and analysis of the current–voltage characteristics (CVCs). The film thicknesses range from 20 to 150 nm at the carbon-to-oxygen (C/O) atomic ratio of 4 : 1. Structural studies show that the films obtained consist of nanographite flakes with the lateral dimensions in the range from 5 to 12 nm and contain different fractional concentrations of sp3/sp2 crystalline phases of carbon. It is established that the structural quality of carbon films decreases with an increase in the annealing temperature from 650°C to 800°C. At the same time, the degree of graphitization increases, which is indicated by Raman spectroscopy data and sheet resistances calculated from the CVCs. Photocurrents are calculated from the temperature dependences of the CVCs; it is found that the samples exhibit photosensitivity in the temperature range from room temperature to –173°C. These results may be useful for designing day and night light sensors and temperature sensors operating in a wide temperature range. [ABSTRACT FROM AUTHOR]

The density of donor-like state distributions in solution-processed indium–zinc-oxide (IZO) thin-film transistors (TFTs) is thoroughly analyzed using photon energy irradiation. This study focuses on quantitatively calculating the distribution of density of states (DOS) in IZO semiconductors, with a specific emphasis on their variation with indium concentration. Two calculation methods, namely photoexcited charge collection spectroscopy (PECCS) and photocurrent-induced DOS spectroscopy (PIDS), are employed to estimate the density of the donor-like states. This dual approach not only ensures the accuracy of the findings but also provides a comprehensive perspective on the properties of semiconductors. The results reveal a consistent characteristic: the Recombination–Generation (R-G) center energy ET, a key aspect of the donor-like state, is acquired at approximately 3.26 eV, irrespective of the In concentration. This finding suggests that weak bonds and oxygen vacancies within the Zn-O bonding structure of IZO semiconductors act as the primary source of R-G centers, contributing to the donor-like state distribution. By highlighting this fundamental aspect of IZO semiconductors, this study enhances our understanding of their charge-transport mechanisms. Moreover, it offers valuable insight for addressing stability issues such as negative bias illumination stress, potentially leading to the improved performance and reliability of solution-processed IZO TFTs. The study contributes to the advancement of displays and technologies by presenting further innovations and applications for evaluating the fundamentals of semiconductors. [ABSTRACT FROM AUTHOR]

In organic photovoltaics (OPVs), the development of efficient light‐harvesting organic donor and acceptor materials and the design of a device structure with appropriate visible light transmittance play an important role in increasing their power conversion efficiency. Light manipulation strategies in OPV are widely used to improve photovoltaic performance. One of the most popular technologies is antireflective coating (ARC), which enhances light utilization in devices. However, ARC has been investigated less in OPV cells than in organic silicon solar cells. Herein, a novel approach that employs the natural biomaterial M13 bacteriophage (M13) as an intermediate layer with a thickness of a few nanometers between the hole transport layer (HTL) and indium tin oxide is investigated. The functional surface hydrophilicity, obtained by genetic manipulation of M13, improves the light transmittance by more than 84% over the visible wavelength range of the OPV cells. Furthermore, it enhances the coherence between the HTL and the photoactive layer. Therefore, the photocurrent density and power conversion efficiency significantly increase, producing a high photovoltaic performance. The proposed approach of using natural biomaterials is the basis for a novel, low‐cost, and eco‐friendly design for light manipulation in solar cells. [ABSTRACT FROM AUTHOR]

The integration of cost-effective and highly efficient oxygen evolution catalysts (OECs) profoundly impacts the performance of semiconductor photoharvesters in solar-driven water splitting. Drawing inspiration from the advantages of various transition metal oxides and hydroxide-based OECs, we demonstrate that the remarkable activity of nanostructured NiFe-(OH)x catalysts can significantly enhance the oxygen evolution efficiency of BiVO4 photoanodes. The optimized BiVO4/NiFe-(OH)x photoanode exhibits an above 300% increase in the photocurrent density over BiVO4, reaching a high value of 4.02 mA cm–2 at 1.23 V vs reversible hydrogen electrode (RHE) under simulated solar light illumination (100 mW cm–2, AM 1.5 G) in a near neutral electrolyte. Our investigations reveal that the NiFe-(OH)x catalyst serves as an effective photohole-extracting layer, leading to the improved separation of photocarriers. The coupling of nanostructured NiFe-(OH)x catalysts also enhances the applied bias photon-to-current conversion efficiency of the BiVO4 photoanodes to 0.78% (at 0.87 V vs RHE). It reduces the water-splitting onset potential by 280 mV. Consequently, the BiVO4/NiFe-(OH)x photoanode exhibits a 2-fold increase in the photocatalytic hydrogen production rate compared to pristine BiVO4. This work underscores the effectiveness of pairing facile NiFe-(OH)x OECs with BiVO4 photoanodes, leading to exceptional photoelectrochemical water oxidation. [ABSTRACT FROM AUTHOR]

In this work, we have done the comparative analysis of Single Gate and Dual Gate pentacene-based organic phototransistors (OPT). The opto-electrical simulations were done using 2-D Silvaco TCAD ATLAS device simulator. The SG-OPT and DG-OPT were simulated to provide deeper insight into behaviour of the two from both device physics perspective and quantitative standpoints. We have conducted an evaluation of both OPTs on account of the various important performance parameters at different electrical and optical bias over a wide spectral range. Our results shows how these different configurational OPT designs can influence the essential performance parameters while observing the variations in drain current, Current density, Energy band Diagrams and the various essential performance parameters such as Responsivity, photosensitivity, spectral response, quantum efficiency etc. [ABSTRACT FROM AUTHOR]