Photoelectric Characteristics Research Articles

Development of optoelectronic properties of a novel graphene oxide/copper phthalocyanine composite: Production and photoelectric characteristics of diode

Novel copper (II) phthalocyanine bearing 3-chloro-4-fluorophenoxy (2) and its graphene oxide (GO)-based composites (2a-2f) were synthesized and characterized. The single crystal of the starting material compound (1) was analyzed for the first time using X-ray diffraction in this study. Phthalocyanine composites containing different percentages of graphene oxide by weight (wt.% GO) were prepared. SEM (scanning electron microscopy) results confirmed the interaction between GO and CuPc (2). In this study, the effects of concentration on the optoelectronic and conductivity properties of CuPc (2), as well as the influence of graphene oxide on the optoelectronic properties of CuPc (2) were extensively investigated. Additionally, the surface morphological properties of the phthalocyanine film were analyzed. Finally, an n-Si/CuPc (2)/Al diode was fabricated, and its photoelectric properties were investigated.

Dual-Source Evaporation Processed Novel NaBiS2 Absorber Material for Eco-Friendly and Stable Photovoltaics.

Exploring and developing novel, low-cost, and environmentally friendly photovoltaic materials is a vital trend in the evolution of solar cell technology. The distinctive properties of alkali bismuth ternary sulfides have spurred increased research and application in optoelectronic devices. In this study, a novel method is reported for preparing NaBiS2 film by sequential thermal evaporation of Na2S and Bi2S3 layers followed by heating post-treatment for the first time, as well as the preparation of solar cells with NaBiS2 as the light-absorbing layer. Based on X-ray diffraction and Raman analysis, the prepared NaBiS2 film is confirmed to be a single-phase material, without the presence of any secondary phases. Additionally, the photoelectric characteristics of NaBiS2 are investigated and incorporated this material into solar cell devices. By optimizing the device architecture, the solar cell utilizing NaBiS2 as the light-absorbing layer achieved a photoelectric conversion efficiency of 2.91%, which is the highest efficiency reported for NaBiS2 solar cells up to now. The research has provided a valuable perspective and path for the development of novel photovoltaic materials in the solar cell field.

Photoelectric characteristic of hybrid thin-film solar cells and metasurface absorbers

Abstract As the demand for high-efficiency, low-cost solar cells continue to increase, existing thin-film solar cells still face many challenges in terms of light absorption efficiency and charge transport performance. To address these issues, we design and study a PEDOT:PSS/CdTe hybrid thin-film solar cell structure combined with a metasurface absorber layer. We use a metasurface structure with a tetragonal embedded ring resonator pattern in the CdTe absorber layer. This structure can produce a strong electric and magnetic field localization effect on the surface of the absorption layer, improving the light absorption rate of the battery. At the same time, the introduction of organic polymer materials (PEDOT: PSS) optimizes the electrode interface quality and reduces the interface defects and composite losses between materials, and further improves the photoelectric conversion efficiency (PCE) of the battery. we introduce traditional absorption enhancement methods (titanium nanoparticle arrays and pyramid TiO2 arrays) to this structure. The solar cell proposed has a spectral response rate of 96.71% and its PCE reaches 35.66%. The research indicates that the new structure holds significant potential for the application of high-efficiency solar cells, offering new ideas for the design and manufacture of solar cells in the future.

Perovskite CsCuClxBr3- x Microcrystals: Band Structure, Photochemical Stability, and Photocatalytic Properties.

Although Pb-based metal halide perovskites (MHPs) have excellent photoelectric characteristics, their toxicity remains a limiting factor for their widespread application. In the paper, a series of CsCuClxBr3-x (x = 1, 2, 3) MHP microcrystals were developed and their hydrogen evolution performance in ethanol and HX (X = Cl, Br) was also studied. Among them, CsCuCl3 microcrystals exhibit high hydrogen evolution performance in both HX and ethanol, attributed to their longest average lifetime and suitable band structure. Additionally, the effect of different sacrificial agents on photocatalytic hydrogen production indicates that the photogenerated hole (h+) plays a critical role. MHPs can maintain a dynamic equilibrium of dissolution and precipitation in HX-saturated aqueous solutions, thereby overcoming the stability issues associated with perovskite. The phase transition of CsCuClxBr3-x during photocatalysis is monitored by the XRD technique. CsCuCl3 shows high stability in saturated HCl aqueous solution, and excellent photocatalytic performance with a hydrogen production rate of CsCuCl3 microcrystals reached 103.98 μmol g-1 at 210 min. Our study expands the development prospects of CsCuCl3 in the field of photocatalytic solar fuel generation.

Top‐Down Fabrication of N‐GQDs Modified SnO2 with Improved Photoelectric Characteristics

AbstractN‐graphene quantum dots (N‐GQDs) are prepared using graphite as a carbon source and ammonia as a nitrogen source by a top‐down approach, and further combined with SnO2 to obtain SnO2/N‐GQDs composites by a hydrothermal method. SnO2/N‐GQDs composites are analyzed by morphology and structure characterization, and the composites with different N‐GQDs content are further investigated by instantaneous photocurrent response (I‐t), electrochemical impedance (EIS), linear scanning voltammetry (LSV), and Mott‐Schottky curves (MS). SnO2/N‐GQDs composites exhibit an obvious increment in photocurrent and a decrement in interface charge transfer impedance. When the addition of N‐GQDs is 1.5wt.%, the I‐t value of SnO2/N‐GQDs reaches the optimum of 3.84 × 10−5 A cm−2, which is 2.3 times as large as that of SnO2. Meantime, the carrier density of SnO2/N‐GQDs reaches 2.67 × 1021cm−3, which is 1.5 times as high as that of SnO2. The improvement is attributed to the combination of SnO2 and N‐GQDs, which promotes more charge carriers to be generated and transported under UV irradiation.

Si-based n++-p–-p+-p–-p++ avalanche diode: Self-consistent modeling for infrared optoelectronic applications

A theoretical approach for modeling electric and photoelectric characteristics of specifically designed Si-based n++-p–-p+-p–-p++ avalanche photodiodes has been developed. The electrostatic characteristics (band bending, built-in electrostatic fields and carrier distributions) and current-voltage characteristics including photocurrent and diode sensitivity to electromagnetic radiation of the near-infrared spectral range have been calculated and analyzed for the room operation temperature. The measured doping profiles in the fabricated prototype of the avalanche Si-based photodiode have been used in the calculations. For a particular set of the photodiode parameters, we have found that the avalanche transport regime occurs at the applied reverse voltage of ~ –47 V across the diode length of 380 μm We have established that the rapid exponential growth of the current densities from 0.01 to 100 μA/cm2 in the range of the applied voltages of –40 to –47 V is inherent for formation of the avalanche-type transport regime. At this, considerable photoresponsibility values of 100 to 30 A/W are predicted for electro-magnetic radiation wavelengths of 0.8 to 1 μA. All the results have been obtained using literature data on field dependences of the impact ionization coefficients, spectral dependences of the optical permittivity (refractive index and extinction coefficient), etc.

Strategic design of carrier transport layer-free homojunction perovskite photodetector

Abstract Perovskite photodetectors (PPDs) have attracted extensive attention due to their unique material properties. However, the use of electron and hole transport layers ( ETLs and HTLs) significantly increases the complexity of design and processing and reduces the reliability of the devices. To address these issues effectively, a simple strategy of eliminating the ETLs and HTLs by employing a perovskite homojunction is proposed. In this study, we examine a numerical design of p-n homojunction-based PPD without the use of carrier transport layers (CTLs), using the Silvaco TCAD simulator. To unlock the potential of the proposed design, the effects of doping concentration, mobility, thickness, and bandgap of p-perovskite and n-perovskite on the PPD photoelectric characteristics are investigated and optimized. The simulation results illustrate that a high-performance CTL-free PPD can be achieved by forming a p-n homojunction using a thin (<200 nm) highly-doped (5 × 1017 cm−3) p-perovskite layer and a thick (>600 nm) lowly-doped (5 × 1014 cm−3) n-perovskite layer with suitable mobility (1 ∼ 10 cm2 V−1 s−1). Under optimized conditions, our findings reveal an optimum detectivity of 7.4 × 1013 Jones at 750 nm, the optimum responsivity is found to be 0.42 A W−1 at 675 nm and the optimum EQE is 84% at 475 nm. These results highlight the promising potential of the p-n homojunction design as a device configuration for producing high-performance and reliable commercial PPDs without any CTL.

Photoelectric characteristic of single-phase InxGa1-xN films with tunable bandgap through RF magnetron sputtering

Photoelectric characteristic of single-phase InxGa1-xN films with tunable bandgap through RF magnetron sputtering

Determination of photoelectric characteristics of two-sided sensitive solar elements

Determination of photoelectric characteristics of two-sided sensitive solar elements

Enhanced Photocatalytic Degradation of Environmental Pollutants Using a Triphenylamine-Based Polymer: Synthesis, Characterization, and Mechanistic Insights.

Conjugated porous organic polymers have sparked growing research attention as photocatalysts owing to their high surface area, tunable pores, and capacity to collect and transfer light energy via their delocalized backbone. However, the synthesis methods for preparing these polymers require difficult experimental setups, such as high polymerization temperature, inert atmosphere, and use of transition metal catalysts. In the present work, a triphenylamine-based conjugated porous polymer (TPA-BPA) has been synthesized employing tris(4-aminophenyl)amine (TPA) and biphenyldicarboxaldehyde (BPA) as precursors via a one-pot Schiff base reaction in ambient conditions in the absence of the metal catalyst. The synthesized TPA-BPA polymer has been characterized using Fourier transform infrared spectroscopy, 13C cross-polarization magic angle spinning nuclear magnetic resonance, Brunauer-Emmett-Teller (BET), thermogravimetric analysis, field emission scanning electron microscopy, high-resolution transmission electron microscopy, valence band X-ray photoelectron spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, powder X-ray diffraction, electron paramagnetic resonance (EPR), and diffuse reflectance spectroscopy (DRS) techniques. The DRS analysis revealed that TPA-BPA has an optical band gap of 2.1 eV, demonstrating its semiconductive nature. The EPR study has shown that the synthesized polymer exhibits an intense radical signal at g = 2.00, confirming free radical generation upon photoexcitation and facilitating the breakdown of organic contaminants by photocatalysis. TPA-BPA possesses an exceptional porous structure with a surface area of 36 m2/g, as confirmed by BET studies, and high thermal stability up to 420 °C. It has been confirmed by photocatalytic studies that TPA-BPA shows effective degradation of methyl orange (92%), Congo red (91.5%), tobramycin (96%), and hydroquinone (85%) under visible light irradiation in 60 min. Owing to these observations, TPA-BPA can be an excellent candidate as a photocatalyst for environmental remediation. These findings pave the way for large-scale manufacturing of metal-free conjugated porous polymers as photocatalysts with variable photoelectrical characteristics.

Improvement of Performance of Perovskite Solar Cell By in-Plane Design

Perovskite solar cells (PSCs) have attracted attention as one of the next-generation solar cell. To enhance power conversion efficiency (PCE) of PSCs, a great deal of research has been conducted so far, mainly in the field of material development. However, in-plane cell design for evaluating the performance of PSCs are currently not standardized. In this study, optimization of device structures was investigated for the aim of to minimize charge transfer losses and improve FF and PCE.The fabrication of perovskite solar cell is as follows; (i) as the electron transport layer (ETL), compact TiO2 and mesoporous TiO2 were deposited on FTO glass substrates by spray coating and spin-coating. (ii) K0.025(Cs0.1FA0.9)0.975PbI3 perovskite was deposited by spin-coating using the anti-solvent method1). (iii) Spiro-OMeTAD was spin-coated as the hole transport layer. (iv) The electrodes were insulated by laser etching. (v) Finally, Au was vacuum-deposited and laser-etched again to fabricate the cell.Throughout the two laser etching stages in the cell fabrication process, adjustments are made to the shapes of the ETL/perovskite layer/HTL and the Au electrode. Specifically, performance was compared for three patterns of devices; (a) round-shaped generator section and current-collecting bridge, (b) shorter distance of current-collecting bridge, (c) shorter distance of current-collecting bridge and same width of current-collecting bridge as generator section. Photoelectric conversion characteristics was determined based on I-V characteristics measured under quasi-sunlight (AM 1.5, 100 mW/cm2) irradiation. In all cases, the shading mask area was kept constant at 0.18 cm2.Figure shows images of three patterns of the results of comparing FF from I-V measurements for each device with varying shapes. It can be seen that even PSCs fabricated from the same material exhibit different FF values depending on the cell shapes. PCE and FF were higher in (b) than in (a), with the highest values observed for devices of (c), in which the collector bridge is shortened and the width is increased. In addition, the series resistance (Rs) and shunt resistance (Rsh) were approximated from the slope of the I-V curve. Among the internal resistances, the series resistance (Rs) decreased, leading to an improvement in FF. This is thought to be due to the decrease of series resistance of electron and hole transfer. Figure 1

Photoelectric Interaction and Photochromic Mechanism of K0.5Na0.5NbO3 Ceramics.

Rare-earth materials are widely used in the optical field due to their rich energy-level structures, and if endowed with photoelectric response characteristics, they are expected to be applied to photoelectric multifunctional devices. In this paper, Ho3+- and Yb3+-codoped K0.5Na0.5NbO3 (KNN) ferroelectric ceramics are synthesized, and the up-conversion and down-conversion luminescence intensity as well as the decay degree after photochromism can be controlled by the content of Yb3+. Strong green luminescence visible to the naked eye is realized, and the maximum luminescence decay is more than 50%. 2 s of color change fully indicates that the ceramic has the characteristics of fast response photochromic, under the most efficient wavelength of 405 nm by changing the irradiation wavelength. By incorporating data from thermal and electrical stimulation experiments, a comprehensive photochromic mechanism diagram is constructed, where the photochromic properties are predominantly governed by defects. It is believed that this work will provide a theoretical basis for the design of high-performance photochromic ceramics.

Yttrium doped barium titanate nanocrystals synthesis using inverse miniemulsion and their properties

This paper highlighted in preparation and their properties of Y3+ doped barium titanate (BaTiO3) nanocrystals using inverse miniemulsion. The yttrium (Y) element dopant as the earlier utilized rare earth was used for barium titanate (BaTiO3) modification. The cubic structure of Y3+ doped BaTiO3 nanocrystals were successfully incubated in stable droplets of inverse miniemulsion under the solvent-thermal treatment condition. The suitable Y3+ doping amount in nanocrystals had positively attributed to reduce the value of bandgap (Eg ), to prolong the fluorescence lifetime, and to improve the photoelectric properties. The photodegradation mechanism and the schematic diagram of fluorescence emission and radical production were suggested for explanation the relation between photoelectric characteristics and photocatalytic properties. The selected 1.0% Y3+ doped nanocrystal provided an excellent photocatalysis candidate for organic compound photodegradation.

Highly Polarization‐Sensitive Solar‐Blind Ultraviolet Photodetection Based on 1D Rb2CuCl3 Microwires

AbstractPolarization‐sensitive solar‐blind ultraviolet (UV) photodetectors are essential in both civilian and military applications. 1D perovskites derivative Rb2CuCl3 holds promise for polarization‐sensitive solar‐blind UV photodetectors due to its wide direct bandgap, anisotropic crystal structure, and long carrier lifetime. However, no studies on the polarization properties of Rb2CuCl3 are reported. Here, the electronic structural anisotropy of Rb2CuCl3 is confirmed by calculating the partial charge density distribution in the ac‐plane and bc‐plane. Then, the Raman‐active modes and corresponding atomic vibration modes are explored within the bc‐plane through joint experimental and theoretical Raman spectroscopy. Besides, angle‐resolved Raman, photoluminescence, and absorption spectroscopy reveal the intriguing anisotropic photoelectric characteristics of Rb2CuCl3 microwires (MWs). By using single Rb2CuCl3 MW as the photoactive layer, a polarization‐sensitive solar‐blind UV photodetector is fabricated, showing high photoresponsivity of 78 mA W−1 and photocurrent anisotropy ratio of ≈1.7 at 265 nm. Importantly, the proposed photodetectors without encapsulation exhibit excellent stability in ambient air, retaining the original photocurrent after two months, showcasing practical applicability. This study underscores the promise of Rb2CuCl3 for high‐performance polarization‐sensitive solar‐blind UV photodetectors, contributing valuable insights into its electronic structure, photoelectric properties, and practical applicability.

Improving photoelectric characteristics of GaN-based green laser diodes by inserting electron blocking layer with gradient Al composition

This paper proposes four new gradient composition electron blocking layer (EBL) structures to enhance the photoelectric performance of GaN-based green laser diodes (LDs). The optical and electrical properties of new structure LDs are theoretically analyzed by LASTIP. It is observed that the implementation of a gradient composition EBL structure increases the effective barrier height for electrons, thereby better inhibiting the electron current overflow from the active region. In addition, the optical field leakage is effectively suppressed, lower threshold current and higher output power are obtained. The four different new structures have obvious differences in the improvement of the hole current injection and slope efficiency of multiple quantum well (MQW) LDs, and the underlying reasons for these phenomena are explored. Simulation results indicate that adopting a gradually descending Al component EBL structure yields optimal improvements in the photoelectric performance of LDs.

Annealing temperature induced variation on the electrical and photoelectrical characteristics of Al/Feq3/p-Si/Al heterojunction diode

Annealing temperature induced variation on the electrical and photoelectrical characteristics of Al/Feq3/p-Si/Al heterojunction diode

Versatile Spiral Donor‐Based Thermally Activated Delayed Fluorescence Materials for Highly Efficient TADF‐OLED and TSF‐OLED Applications

AbstractHerein, a design strategy is explored for thermally activated delayed fluorescence (TADF) materials by employing the meta‐linkage of the spiral‐donors 10H‐spiro[acridine‐9,9'‐thioxanthene] (DspiroS) and 10',10'‐dimethyl‐10H,10'H‐spiro[acridine‐9,9'‐anthracene] (DspiroAc) to the robust acceptor 2,4,6‐triphenyl‐1,3,5‐triazine (TRZ). Two distinct TADF materials, m‐DspiroS‐TRZ and m‐DspiroAc‐TRZ, exhibiting unique photophysical properties and performance characteristics were synthesized. Interestingly, even subtle modifications in the molecular architecture can significantly impact the organization of materials in their aggregated state, thereby governing photophysical properties and inducing corresponding alterations in photoelectric characteristics. Notably, m‐DspiroS‐TRZ exhibits superior photophysical properties and exciton dynamics data, achieving a high photoluminescence quantum yield (PLQY) value of up to 95.9% and a rapid reverse intersystem crossing (RISC) rate (𝒌𝑹𝑰𝑺𝑪) of 1.0 × 106 s−1. This positions m‐DspiroS‐TRZ as a potentially excellent terminal emissive and sensitizing host material, inspiring further exploration of its applications in electroluminescence. Consequently, TADF organic light‐emitting device (TADF‐OLED) and TADF‐sensitized fluorescence (TSF‐OLED) based on m‐DspiroS‐TRZ have achieved maximum external quantum efficiencies (EQEs) of 31.8% and 34.5%, respectively, demonstrating the significant versatile potential of m‐DspiroS‐TRZ.

Interface and Defect Engineering in 3D Co3O4‐Ov/TiO2 to Boost Simultaneous Removal of BPA and Cr(VI) upon Photoelectrocatalytic/Peroxymonosulfate (PEC/PMS) System

AbstractThe combination of photoelectrocatalytic (PEC) and peroxymonosulfate (PMS) is an innovative strategy for environmental treatment. And fabricating a highly efficient photoelectrode is the most pivotal factor in PEC reactions. This study designs an advanced Co3O4‐Ov/TiO2 photoelectrode by a dual‐modification strategy encompassing interface engineering and defect engineering. The photoelectric characterization validates the synergy of oxygen vacancies and dual heterojunctions. Simulated electron density distribution and Kelvin probe force microscopy (KPFM) elucidate the charge transfer pathway between Co3O4‐Ov and TiO2. 1O2 and SO4 .− are confirmed to be primarily responsible for the BPA oxidation in PEC/PMS system by radical scavenger experiments and the EPR technique. And the attack sites of BPA are precisely identified based on the Fukui index. Furthermore, density functional theory (DFT) calculations testify that Co3O4‐Ov can improve the adsorption capacity of PMS and reduce the energy barrier of the reaction process, while XPS analysis showed Co3+/Co2+ redox couple can accelerate PMS activation. Enhanced anode oxidation can effectively promote cathode reduction and consequently Co3O4‐Ov/TiO2‐PMS/PEC system presents a superior removal of both pollutants within only 15 min with fast kinetics (0.15 min−1 for BPA, 0.29 min−1 for Cr(VI)). This work provides unique insight into designing a highly efficient PMS/PEC system for simultaneous pollutant treatment.

Influence of Silicon-Based Photoelectric Material Spectral Characteristics on Radiation Spectroscopy Thermometry

To research the influence of the photoelectric response characteristics of radiation thermometry, a high-temperature blackbody radiation spectrum measurement experimental system is built by using the standard blackbody furnace, optical-fiber spectrometer with silicon-based photoelectric detection material. By setting different integration times of the spectrometer, the standard blackbody radiation spectrum measurement at different temperatures is carried out. The influence of the photoelectric response characteristics parameters is analyzed in detail. Therefore, the linear range between fitting band and spectral response intensity of radiation spectrum thermometry parameters is optimized. On this basis, through the standard blackbody radiation temperature measurement, the influence of the optimal parameter fitting band and the linear interval of spectral response intensity on the radiation temperature measurement results are verified. The influence of the mentioned photoelectric detection response characteristics on the spectral radiation thermometry has an important reference value for improving the accuracy of the spectral radiation thermometry.

Substituent Regulating Porphyrin Derivatives for Efficient Photocatalytic Hydrogen Evolution

AbstractPorphyrin and its derivatives have been seen as a type of potential organic photocatalyst for photocatalytic hydrogen evolution. Substituent regulation as a simple method can effectively regulate the photoelectric characteristic of organic semiconductors. Herein, we designed three porphyrin derivatives attached with different substituents (PP‐NH2, PP‐OH and PP‐COOH). Through a facile substituent optimization strategy, the photoelectric properties of these porphyrin derivatives show an obvious difference, which leads an optimized photocatalytic hydrogen evolution efficiency. The porphyrin derivative with carboxyl presents a reduced impedance, and a better charge separation. Compared to the amino group, PP‐COOH with carboxyl, achieved a high hydrogen evolution rate of 2.20 mmol g−1 h−1 (over 20 times than that of PP‐NH2). Moreover, enhanced stability was observed in PP‐COOH rather than PP‐OH, because of the lower HOMO energy level. And the ionization of carboxyl in water negatively charges the porphyrin derivatives and forms a relatively stable sol. This result further increases the operation stability of PP‐COOH, during photocatalytic hydrogen evolution. This study presents a promising design strategy for long‐lifetime photocatalysts for hydrogen evolution.