Short-circuit Photocurrent Density Research Articles

Influence of Plasmonic Au@Cl/N Co‐doped Carbon Dots on the Performance of Dye‐Sensitized Solar Cells

ABSTRACTThe synergistic influence of the LSPR (localized surface plasmon resonance) of gold nanoparticles (Au NPs) and the effect of nitrogen and chlorine co‐doped carbon dots (Cl/N‐CQDs) on dye‐sensitized solar cells (DSSCs) performance are investigated. The gold NPs are coated with a thin layer of Cl/N‐CQDs to produce the Au@Cl/N‐CQDs structure. DSSCs are fabricated by using Au@Cl/N‐CQDs as co‐sensitizer. The focus of this work is to examine the effects of plasmonic Au NPs and carbon dots in addition to their synergistic effect by capping the Au NPs with Cl/N‐CQDs, and track their influence in DSSCs. N719 as ruthenium‐based dye, and natural dyes including betanin, crocin, carthamin, curcumin, chlorophyll, mallow, and lawsone are selected and applied in the DSSCs co‐sensitized by Au@Cl/N‐CQDs. The power conversion efficiency (PCE) of DSSCs using all of the selected dyes is enhanced upon using the Au@Cl/N‐CQDs. It is due to the improvement in VOC (open circuit voltage) and JSC (short circuit photocurrent densities) relative to the use of dyes alone. Based on computational results, Au@Cl/N‐CQDs cause a red‐shift in comparison with pure dyes. The TD‐DFT (time‐dependent density functional theory) results show that the orbitals from the Au@Cl/N‐CQDs in dye/Au@Cl/N‐CQDs have contribution in most of the absorptions. In other words, electrons from HOMO (highest occupied molecular orbital) of Au@Cl/N‐CQDs is transferred to the LUMO (lowest unoccupied molecular orbital) of dye, in most cases.

Simulation of the functionality of ZnO, TiO2 and Ta2O5, and MoO2 carrier selective contacts of GaAs0.99Bi0.01 nanowire-based solar cells

Abstract Photovoltaic performance of perpendicularly aligned GaAs0.99Bi0.01/CSC/ITO core-shell nanowire solar cell is thoroughly investigated in this simulation based theoretical study for both electron selective contact (ESC) and hole selective contact (HSC) as carrier selective contact (CSC) shell around GaAs0.99Bi0.01 core nanowire. The overall performance has been compared with radial PiN doped GaAs0.99Bi0.01 NWSC to mark the improvement caused by carrier selectivity. ZnO, TiO2, and Ta2O5 materials have been chosen as ESC material and MoO2 is chosen as HSC material in order to carry out this comparative study. We have thoroughly performed geometry optimization test over a wide range of periods in order to select the optimized ITO (Indium Tin Oxide) thickness for obtaining maximum photo current generation. The maximum short circuit photo current density (Jsc) of 38.76 mA/cm2 is obtained with ZnO coated nanowire solar cell (NWSC) for a pitch (P) of 400 nm and ITO shell thickness of 90 nm. For this optimized geometry, TiO2, Ta2O5 and MoO2 coated structures offered Jsc of 35.82 mA/cm2, 35.69 mA/cm2, and 35.27 mA/cm2 respectively and the uncoated NW generated Jsc of 31.15 mA/cm2. The planar structure without coating exhibits a Jsc of 24.86 mA/cm2, which is significantly lower than the nanostructured solar cells. Finally Lumerical 3D charge transport simulator is used to perform the electrical stimulation of ZnO coated structure, which offers maximum ideal Jsc. A detailed electrical performance analysis of GaAs0.99Bi0.01/CSC/ITO unit nanowire solar cell for ZnO, TiO2, Ta2O5 as ESC and MoO2 as HSC have also been covered in this article which reveals that ZnO as ESC possesses promising potential for designing highly efficient solar cells as it offers a photo conversion efficiency(PCE) of the order of 25% and open circuit voltage (Voc) even for very less minority carrier lifetime (Ʈn) 0.1 ns of GaAs0.99Bi0.01 and 1ps Ʈn of ZnO.

Characterization and properties of solid-state nanocomposite Acacia gum electrolytes with emphasis on diverse applications

A novel, natural, eco-friendly, solid-state Acacia gum nanocomposite electrolyte has been prepared with different weight ratios of nanoparticle ZrO2 introduced to the standard composition of 70% Acacia gum and 30% ZnSO4·7H2O. Sequential examinations, encompassing XRD, and FTIR, were conducted to evaluate the amorphous characteristics, complexation nature, and interaction of dopant nanoparticles within the acacia-salt electrolyte matrix network. The optimum ionic conductivity of nanocomposite electrolytes was found using electrochemical impedance analysis. The remarkable ionic conductivity was achieved for the electrolyte sample consisting of 10% nanoparticle ZrO2 introduced to the standard composition of 70% of Acacia gum and 30% of ZnSO4·7H2O(AZR4) at 100 °C, 6.1×10−3S/cm, at room temperature (RT) the electrolyte sample exhibited conductivity value of 1.13×10−3 S/cm. Additionally, an examination of the dielectric characteristics dependent on frequency demonstrated the existence of space charge polarization in the electrolyte and a notable tail in the low-frequency area. Through the parameters of the dielectric modulus, the research also investigated the hopping mechanism and relaxation time. Furthermore, nano-composite electrolytes were employed in the construction of solar cell devices. The outstanding results were obtained for electrolyte upon (10 wt%) nanoparticle-introduced, overall power conversion efficiency (ƞ) reached 5.38%, short-circuit photocurrent density (Jsc) 10.92 mA/cm2, open-circuit voltage (Voc) at 735 mV, and fill factor (FF) at 0.63.

Society based photovoltaic application of dye sensitized solar cell of Indium doped ZnO photoanode using cactus fruit via solvothermal method

In this work, Indium doped zinc oxide nanoparticles with various molar concentrations were synthesized by solvothermal method. The prepared nanoparticles were analysis using characterization. The structural properties of X-ray diffraction (XRD) used to obtain the hexogonal structure of nanoparticles. The surface morphology of prepared nanoparticles was magnification by Field Emission Scanning Electron Microscope (FESEM), The optical bandgap and functional groups were obtained by Ultra-Violet Visible spectra and Fourier Transform Infrared spectroscopy. Then the fabrication of dye sensitized solar cell based on indium doped ZnO photoanode using cactus dye. The performance of J-V characterization demonstrate a high short-circuit photocurrent density of 2.83 mA/cm2 and open circuit voltage of 0.63with relevant solar cell efficiency of 0.92 % whereas DSSCs made from pure ZnO NPs exhibited a current density of 8.02 mA/cm2 with 0.19 % efficiency. To increase the light-harvesting efficiency, both the photoanode and photons absorption could be optimized and it good response for UV-region. From this reports dye and photoanode are suitable to increase the efficiency of solar cell.

Effect of nickel oxide concentration on titanium oxide bilayer photoanode for dye-sensitized solar cell application

The mesoporous titanium oxide has attracted significant attention as a photoanode material for Dye-Sensitized Solar Cells (DSSCs). In the present work, we coated a planar NiO layer on the TiO2 film to minimize charge recombination with the dye and/or electrolyte molecules. The structural, morphological, elemental, optical, and electrical properties of the TiO2 and bi-layered TiO2/NiO films were studied using various characterization techniques. DSSCs based on N3 dye-sensitized TiO2 and bi-layered TiO2/NiO films were fabricated using PI as the redox electrolyte. The photocurrent density–voltage (J–V) characteristics of the DSSCs were studied using a solar simulator. Various parameters, such as open-circuit voltage (Voc), short-circuit photocurrent density (Jsc), and fill factor (FF), were calculated from the J–V characteristics. DSSCs based on bi-layered TiO2/NiO films showed superior performance compared to bare TiO2 films. The J–V characteristics of bilayer film shows enhanced open-circuit voltage (Voc) ~ 0.56 V, short-circuit current density (Jsc) ~ 2.14 mA/cm2, fill factor (FF) ~ 75%, and efficiency (ƞ) ~ 0.91%. The TiO2/NiO solar cell showed a ~ 28% increase in efficiency compared to TiO2-based DSSC. Hence, the bi-layered TiO2/NiO films have potential applications in optoelectronic and photovoltaic devices.

Eco-friendly guar gum composites as solid-state electrolytes

Solid-state Guar gum electrolytes were prepared through the solution casting technique, employing a composition of 70 % Guar gum and 30 % ZnSO4·7H2O(GZ3). Different weight concentrations of nano ZrO2 (2.5 %, 5 %, 7.5 %, and 10 %) were introduced into the present Guar gum electrolytes. As prepared ZrO2 nanofiller substituted Guar gum electrolytes were examined by XRD, FTIR, DSC, and SEM to evaluate the amorphous characteristics, complexation, glass transition temperature, and surface morphology, respectively. Electrochemical impedance was utilized to examine the frequency-dependent ionic conductivity and dielectric properties of prepared ZrO2 nanofiller-substituted Guar gum electrolytes. At a temperature of 100 °C, the Guar gum electrolyte with10 % Nano ZrO2 exhibited an ionic conductivity of 3.19 × 10−3 S/cm, whereas, at room temperature (RT), it recorded a value of 1.09 × 10−3 S/cm. The activation energy for these electrolytes varied within the range of 0.26 eV–0.39 eV. Furthermore, an investigation of the frequency-dependent dielectric properties revealed a significant tail in the low-frequency region and the presence of space charge polarization within the electrolyte. The study also explored the relaxation time and hopping mechanism through dielectric modulus parameters. Moreover, a flexible Zn-based electrochemical cell was fabricated using a formulation comprising 70 % Guar gum, 30 % Zinc salt, and 10 % Nano ZrO2. The outcomes revealed an open circuit voltage of 0.82V, a discharge rate of 0.04C sustained over 25 h, with an average current discharge rate of approximately 1.4 mA per hour, resulting in an electrochemical-specific capacity of around 45mAh/g. Additionally, a solar cell device was fabricated using Guar gum electrolytes, and the photovoltaic parameters were computed. The maximum overall power conversion efficiency (ƞ) reached 4.79, with short-circuit photocurrent density (Jsc) at 9.66 mA/cm2, open-circuit voltage (Voc) at 725 mV, and fill factor (FF) at 0.65.

Combined experimental and DFT investigation on photovoltaic performance of low-cost metal-free organic dye-sensitized solar cells

Metal-free organic dyes, viz. eosin yellow (eosin-Y), fluorescein and curcumin were used as sensitizers in zinc oxide (ZnO) nanoparticles thin film photoanode based dye-sensitized solar cell (DSSC) and also investigated by density functional theory (DFT). UV–vis spectrophotometer was employed to determine absorption feature of dyes in solar spectrum, adsorption tendency towards ZnO photoanode surface, molar-extinction coefficient and desorbed dye molecules from the photoanode surface. The photovoltaic performance of metal-free organic DSSCs employing imidazole based liquid electrolyte and platinum counter electrode was evaluated under standard light exposure of 85 mW/cm2. Among the dyes, eosin-Y DSSC delivered overall energy conversion efficiency (η) of 0.95 % with short-circuit photocurrent density (Jsc) of 2.98 mA cm−2, open-circuit photovoltage (Voc) of 0.54 V and fill factor (FF) of 0.50, which was about 20 % and 40 % higher than that of the energy conversion efficiency of DSSCs sensitized with fluorescein and curcumin dyes, respectively. The better photovoltaic performance exhibited by the eosin-Y DSSC is credited to its high molar extinction coefficient, intense light absorption in the solar spectrum and good adsorption on ZnO thin film photoanode surface. The maximum driving force for dye molecules regeneration and electron injection value of eosin-Y dye attached on the surface of ZnO cluster (eosin-Y + ZnO) resulted in higher Voc. The outcomes of this experimental data are in well agreement with DFT results.

The Effect of Multi-Fields Synergy from Electric/Light/Thermal/Force Technologies on Photovoltaic Performance of Ba0.06Bi0.47Na0.47TiO3 Ferroelectric Ceramics via the Mg/Co Substitution at A/B Sites.

Currently, it is widely reported that the photovoltaic effect in ferroelectric materials can be promoted by the application of a piezoelectric force, an external electric field, and intense light illumination. Here, a semiconducting ferroelectric composition is introduced, (1-x) Ba0.06Bi0.47Na0.47TiO3-xMgCoO3 (abbreviated as xMgCo, where x=0.02-0.08), synthesized through Mg/Co ions codoping. This process effectively narrows the optical bandgaps to a spectrum of 1.38-3.06eV. Notably, the system exhibits a substantial increase in short-circuit photocurrent density (Jsc), by the synergy of the electric, light, and thermal fields. The Jsc can still be further enhanced by the extra introduction of a force field. Additionally, the Jsc also shows an obvious increase after the high field pre-poling. The generation of a considerable number of oxygen vacancies due to the Co2+/Co3+ mixed valence state (in a 1:3 ratio) contributes to the reduced optimal bandgap. The integration of Mg2+ ion at the A-site restrains the loss and sustains robust ferroelectricity (Pr=24.1µCcm-2), high polarizability under an electric field, and a significant piezoelectric coefficient (d33=102pCN-1). This study provides a novel perspective on the physical phenomena arising from the synergy of multiple fields in ferroelectric photovoltaic materials.

Improved charge separation by anatase TiO2 nanorod arrays for efficient solid-state PbS quantum-dot-sensitized solar cells

To improve the charge separation and transporting between PbS/TiO2 interface in PbS quantum-dot-sensitized solar cells, a 400 nm length anatase TiO2 nanorod array was successfully prepared by the conversion from ZnO nanorod array immersed in a 75 mM ammonium hexafluorotitanate acid solution. The influence of different immersion time on the microstructure, crystal phase and light absorption of the anatase TiO2 nanorod arrays were systematically studied. The PbS quantum dots (QDs) were deposited on the anatase TiO2 nanorod array via spin-coating-assisted successive ionic layer absorption and reaction (spin-SILAR) procedure using 5 mM PbI2 precursor solution, 5 mM Na2S·9H2O solution and 1% EDT/ethanol (1/99, v/v) solution. The solid-state PbS QD-sensitized anatase TiO2 nanorod array solar cell with the structure of FTO/TiO2 compact layer/PbS QD-sensitized anatase TiO2 nanorod array/spiro-OMeTAD/Au was assembled for the first time, and the champion device exhibited a photoelectric conversion efficiency of 5.47% with an open-circuit voltage of 0.62 V, a short-circuit photocurrent density of 13.71 mA cm-2 and a fill factor of 64.28%.

Highly Efficient DSSCs Sensitized Using NIR Responsive Bacteriopheophytine-a and Its Derivatives Extracted from Rhodobacter Sphaeroides Photobacteria.

Employing naturally extracted dyes and their derivatives as photosensitizers towards the construction of dye-sensitized solar cells (DSSCs) has been recently emerging for establishing sustainable energy conversion devices. In this present work, Rhodobacter Sphaeroides Photobacteria (Rh. Sphaeroides) was used as a natural source from which Bacteriopheophytine-a (Bhcl) dye was extracted. Further, two cationic derivatives of Bhcl, viz., Guanidino-bacteriopheophorbide-a (Gua-Bhcl) and (2-aminoethyl)triphenylphosphono-bacteriopheophorbide-a (2AETPPh-Bhcl) were synthesized. The thus obtained Bhcl, Gua-Bhcl and 2AETPPh-Bhcl were characterized using liquid chromatography-mass spectrometry (LC-MS) and their photophysical properties were investigated using excitation and emission studies. All three near-infrared (NIR) responsive dyes were employed as natural sensitizers towards the construction of DSSC devices, using platinum as a photocathode, dye-sensitized P25-TiO2 as a photoanode and I-/I3- as an electrolyte. DSSCs fabricated using all three dyes have shown reasonably good photovoltaic performance, among which 2AETPPh-Bhcl dye has shown a relatively higher power conversion efficiency (η) of 0.38% with a short circuit photocurrent density (JSC) of 1.03 mA cm-2. This could be attributed to the dye's natural optimal light absorption in the visible and NIR region and uniform dispersion through the electrostatic interaction of the cationic derivatives on the TiO2 photoanode. Furthermore, the atomic force microscopy studies and electrochemical investigations using cyclic voltammetry, electrochemical impedance spectroscopy and Bode's plot also supported the enhancement in performance attained with 2AETPPh-Bhcl dye.

Enhancing optoelectronic properties of phosphonic acid based dyes via donor unit variation: A DFT/TD-DFT investigation

In this work, nine phosphonic acid-based dyes adopting the structure D-π-A′-π-A were designed and examined using the density functional theory (DFT) approach to assess their potential application in dye-sensitized solar cells (DSSCs). By incorporating various donor moieties, including carbazole, triphenylamine, phenothiazine, phenoxazine, and coumarin, the relevant key parameters to short-circuit photocurrent density and open-circuit voltage of the designed dyes were assessed. These parameters include the driving force of electron injection (ΔGinj), the spontaneity of dye regeneration (ΔGreg), the charge transfer distance (DCT), the reorganization energies, and the nonlinear optical (NLO) properties were computed. All calculations were performed via the implicit CPCM method in chloroform as solvent medium. The calculated results reveal that the incorporation of different donor units resulted in a narrower bandgap, higher molar extinction coefficient, red-shift in the absorption spectra, better intramolecular charge transfer, and increase in light-harvesting efficiency for dyes where the donor unit is connected by the phenyl in contrast to the T-shaped structure where the donor unit is connected via the nitrogen atom. These findings offer valuable insights into optimizing the optoelectronic properties of phosphonic acid-based dyes for potential use in DSSCs.

Fabrication of a free-standing Ti3C2T x -PTh counter electrode via interfacial polymerization for dye-sensitized solar cells.

The current work involves the fabrication of a MXene-Polythiophene (Ti3C2T x -PTh) composite via interfacial polymerization, alongside its deployment as a counter electrode (CE) or photocathode in dye-sensitized solar cells (DSSCs). The structural properties of the synthesized materials were investigated through a comprehensive array of techniques, including X-ray diffraction (XRD), fourier-transform infrared (FT-IR) spectroscopy, high resolution scanning electron microscopy (HRSEM), energy-dispersive X-ray analysis (EDAX), and X-ray photoelectron spectroscopy (XPS). The electrochemical performance, assessed via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), revealed that the Ti3C2T x -PTh CE exhibits superior electro-catalytic activity, and reduction in charge transfer resistance compared to other individual CEs. These observations are in concordance with the data obtained from Tafel analysis. The incorporation of Ti3C2T x sheets into the composite significantly augmented its catalytic efficacy for triiodide reduction, manifesting in elevated short-circuit photocurrent density and enhanced fill factor metrics. A DSSC utilizing the Ti3C2T x -PTh CE exhibited a power conversion efficiency (PCE) of 5.83%, which stands on par with that of traditional Pt CEs. Thus, the Ti3C2T x -PTh CE material is posited as a viable, cost-efficient alternative to Pt, heralding a new era in the engineering of counter electrodes for the next generation of DSSCs.

Rotaxane-Functionalized Dyes for Charge-Rectification in p-Type Photoelectrochemical Devices.

A supramolecular photovoltaic strategy is applied to enhance power conversion efficiencies (PCE) of photoelectrochemical devices by suppressing electron-hole recombination after photoinduced electron transfer (PET). Here, the author exploit supramolecular localization of the redox mediator-in close proximity to the dye-through a rotaxane topology, reducing electron-hole recombination in p-type dye-sensitized solar cells (p-DSSCs). Dye PRotaxane features 1,5-dioxynaphthalene recognition sites (DNP-arms) with a mechanically-interlocked macrocyclic redox mediator naphthalene diimide macrocycle (3-NDI-ring), stoppering synthetically via click chemistry. The control molecule PStopper has stoppered DNP-arms, preventing rotaxane formation with the 3-NDI-ring. Transient absorption and time-resolved fluorescence spectroscopy studies show ultrafast (211 ± 7 fs and 2.92 ± 0.05ps) PET from the dye-moiety of PRotaxane to its mechanically interlocked 3-NDI-ring-acceptor, slowing down the electron-hole recombination on NiO surfaces compared to the analogue . p-DSSCs employing PRotaxane (PCE = 0.07%) demonstrate a 30% PCE increase compared to PStopper (PCE = 0.05%) devices, combining enhancements in both open-circuit voltages (VOC = 0.43 vs 0.36V) and short-circuit photocurrent density (JSC = -0.39vs -0.34mA cm-2 ). Electrochemical impedance spectroscopy shows that PRotaxane devices exhibit hole lifetimes (τh ) approaching 1 s, a 16-fold improvement compared to traditional I- /I3 - -based systems (τh = 50ms), demonstrating the benefits obtained upon nanoengineering of interfacial dye-regeneration at the photocathode.

Enhanced ZnO-based ETL and nanostructured interface modification for improved perovskite solar cells efficiency

Compared to standard silicon solar cells and other thin film cells, perovskite solar cells (PSCs) can achieve high power conversion efficiency and reduce the production costs. ZnO-based ETL in perovskite solar cells provides a lot of benefits, such as low processing temperature and high mobility. However, the reported instability of perovskite layers placed atop ZnO, resulting in poor device performance, has prevented it from being widely used in perovskite solar cells, though. In this work, an innovative way of insuring device performance and longer-term stability is proposed via the incorporation of a novel efficient process. Herein, a V-doped ZnO/Y-doped TiO2 electron transport bilayer was developed to combine the benefits of strong electron extraction and minimal interfacial recombination. This combined approach of engineering both the improved performance of VZnO as ETL and YTiO2 flower like structures at the interface ETL/Perovskite results in large improvements in the performance of the PSC. V-doped ZnO (VZnO) was introduced into the PSC structure as an ETL, due to its excellent electrical and optical properties, to improve electron extraction efficiency, with a doping amount of 4 at.% of vanadium. The latter has been optimized in our previous study. On the other hand, extrinsically doping TiO2 with an amount of 5 at.% of Yttrium (YTiO2) was utilized to enhance its physicochemical properties. The PSC based on VZnO/YTiO2 bilayer ETL possess the best PCE of 15.1%, compared to 9.4% in the pristine ZnO-based ETL solar cell, with the open-circuit voltage (Voc) of 923 mV, short-circuit photocurrent density (Jsc) of 22 mA cm−2, and fill factor (FF) of 74%. Obtained improvements are ascribed to the suppressed charge recombination via the incorporation of YTiO2 flower-like nanostructures at the interface VZnO/perovskite and the enhanced electron transporting in the resulting ETL bilayer structure.

The effect of defects induced by polarization on bandgap evolution and photovoltaic performance in KN-based semiconducting ferroelectric ceramics

The high-field polarization enables bandgap-engineered ferroelectric perovskite oxides to further enhance their photovoltaic performance. However, research on the mechanism of the high-field polarization-enhanced ferroelectric photovoltaic effect lacks understanding in terms of bandgap evolution. In this work, the ceramics [KNbO3]1−x−[SrNi0.5Hf0.5O3−δ]x(KNSNH100x, x = 0.02 − 0.08), prepared by the solid phase method, exhibit good ferroelectricity and four absorption bandgaps, three of which have sub-bandgaps generated by Ni. The effect of increased defects induced by high-field polarization on bandgap evolution and photovoltaic properties was investigated. The increase in defect concentration in KNSNH2 induced by high-field polarization is the cause of the variation in bandgap structure in KNSNH2. Structural refinement suggests that the change in the bandgap after polarization can be induced by the lattice distortion. The evolution of bandgap structure after polarization in KNSNH2 lead to an enhancement of visible light absorption, which further improve the photovoltaic performance by produced more carriers. A two-fold enhancement of short-circuit photocurrent density (Jsc) under simulated solar irradiation is achieved in the KNSNH2 sample by polarization. This work provides new insights into the effect of defect induced by polarization on enhancing ferroelectric photovoltaic performance and the mechanism of bandgap evolution.

Studies on photovoltaic properties of BFO/WO3 bilayer thin films for solar energy harvesting applications

BFO possess high remnant polarization (∼100 μC/cm2) and low direct band gap (∼2.7 eV) having potential for photovoltaic (PV) applications. In the present work, WO3 insulating layer is utilized with BFO and BFO/WO3 bilayer thin film structure is fabricated for reducing the leakage current along with possessing the low band gap and high ferroelectric polarization. In BFO/WO3 bilayer structure, the WO3 nanostructured thin film layer was fabricated utilizing rf-magnetron sputtering technique under the optimized parameters while BFO thin film layer was fabricated by altering the incident energy of excimer laser (150 mJ − 250 mJ) in Pulsed Laser deposition technique. BFO/WO3 bilayer structure prepared at 200 mJ laser energy demonstrated the superior ferroelectric properties (Ps = 63.24 µC/cm2 and Pr = 25.94 µC/cm2) with high values of short circuit photocurrent density (Jsc = ∼18 mA/cm2) and open-circuit voltage (Voc = ∼320 mV) under the UV illumination of Intensity = 160 mW/cm2 and λ = 355 nm. Obtained results suggest the utilization of prepared BFO/WO3 bilayer thin film structures on future novel energy harvesting purposes.

Bulk photovoltaic and photoconductivity effects in two-dimensional ferroelectric CuInP2S6 based heterojunctions

The construction of two-dimensional heterojunctions has significantly expanded the modulation degrees of freedom in two-dimensional materials, which has led to the emergence of numerous advanced microelectronics and optoelectronic devices. Extensive research has been conducted on the photovoltaic and photoconductivity effects to achieve higher photodetection performance in heterojunction-based devices. However, the bulk photovoltaic effect, which has excellent potential for applications in self-powered optoelectronics, microelectronics, and energy conversion devices, has not received enough attention. Herein, we construct a two-dimensional ferroelectric heterojunction using multi-layered CuInP2S6 (CIPS) and MoS2 nanoflakes and investigate its photoconductivity effect for photodetection. Furthermore, we observe and analyze the bulk photovoltaic effect in the heterojunction. The photoelectric effect in the MoS2 layer contributes to the photoconductivity effect of the heterojunction, while the room-temperature polar ordering in CIPS contributes to the bulk photovoltaic effect. The heterojunction exhibits high specific detectivity (D*) of 1.89 × 109 Jones, when the optical power intensity is 4.71 mW/cm2. Moreover, the short-circuit photocurrent density is high, reaching about 1.23 mA/cm2 when the optical power intensity is 0.35 W/cm2. This work highlights the potential application of two-dimensional ferroelectric materials in multifunction devices with self-powered detection and energy conversion capabilities.

Impact of Mn doping on the ferroelectric photovoltaic effect in multidomain BiFeO3 thin films under above-bandgap illumination

While recent studies have revealed that chemical doping can enhance the photovoltaic (PV) response of ferroelectrics under light with photon energy (hν) lower than the bandgap energy (E g), its impact under above-bandgap illumination (hν > E g) is not fully understood. In this study, the PV response at hν > E g of Mn-doped BiFeO3 (BFO) thin films with a periodic stripe domain pattern is investigated. The short-circuit photocurrent density (J sc) and open-circuit voltage decrease with increasing Mn content. Analyses of the light-polarization angle dependence of J sc indicate that the PV response arises primarily from the non-centrosymmetric nature of crystal lattices in both the bulk and domain wall (DW) regions. In contrast, the contribution of local electric fields (E local) across DWs which dominates the PV response of undoped BFO films is significantly suppressed by doping. We consider that a screening effect by charged defects leads to a suppressed E local in the Mn-doped films.

Enhanced Performance of Perovskite Solar Cell via Controlling Layer Thickness

In this study, Perovskite material methylammonium lead iodide (CH3NH3PbI3) was successfully fabricated using a two-step sequential solution deposition method. The precursor solution of lead iodide was first spin-coated, followed by immersing the film into a solution of CH3NH3I to form the Perovskite layer. The Perovskite material was then successfully applied as a light-harvesting material in Perovskite solar cells. The power conversion efficiency of the devices was optimized by varying TiO2 blocking layer, TiO2 mesoporous layer, and perovskite capping layer thickness. The best Perovskite solar cell exhibits a power conversion efficiency of 7.72% with a short-circuit photocurrent density JSC of 17.26 mA/cm2, an open-circuit photovoltage VOC of 0.94 V, and a fill factor of 47.6%; with the thicknesses of TiO2 blocking layer, TiO2 mesoporous layer, and perovskite capping layer of 100 nm, 200 nm, and 400 nm, respectively. The results show that Perovskite material has potential for solar cell application.

Hydrazonothiazole dyes for enhanced dye-sensitized solar cells in greenhouse applications: Achieving high power conversion efficiency and long-term stability

Dye-sensitized solar cells (DSSCs) offer a cost-effective and attractive alternative to traditional solar cells for greenhouse applications. Hydrazonothiazole dyes (MHS-1-4) have been investigated as a viable DSSC technology, with researchers designing dyes that absorb light in the green region, while transmitting light in the red and blue regions, making them the ideal fit for plant growth. Sensitized devices display impressive power conversion efficiency (PCEs) ranging from 6.27 to 8.85%, with MHS-4 DSSCs achieving an 8.85% power conversion efficiency, a short-circuit photocurrent density of 17.90 mA cm−2, and a maximum incident monochromatic photon-to-electron conversion efficiency (IPCE) of 80%. Furthermore, DSSCs based on MHS-4 demonstrate excellent long-term stability, sustaining nearly constant power conversion efficiency after exposure to one-sun illumination for 1000 h. This breakthrough study demonstrates the potential for hydrazonothiazole dyes in DSSCs, marking a significant step forward in the development of cost-effective solar cell technology compatible with plant growth. With MHS-1-4 dyes' ability to effectively convert photoelectric energy throughout the visible range, and even into the near-infrared (NIR) region up to 900 nm, they offer a new benchmark for DSSC technology.