Applications In Optoelectronic Devices Research Articles

Elementally Doped Carbonized Polymer Dots: Control of Optical Properties and Their Versatile Applications

AbstractCarbonized polymer dots (CPDs) are a class of luminescent nanomaterials formed through cross‐linking and polymerization. Owing to their excellent biocompatibility, ease of synthesis, good aqueous dispersion, high chemical stability, unique cross‐linking structure, and modifiable surface properties, CPDs have attracted significant attention. However, pure CPDs exhibit certain limitations in terms of optical performance, particularly in terms of fluorescence intensity, phosphorescence intensity, and emission wavelength tunability, which may not meet the requirements of specific applications. To address these limitations, doping CPDs with various elements, such as nitrogen (N), sulfur (S), and phosphorus (P) to modify their band structure and surface functionalization can significantly enhance their optical properties and photochemical stability, thereby expanding their application potential. This paper reviews the main synthesis methods for elementally doped CPDs, examines the effects of different types of elemental doping on their photochemical properties, and explores promising applications in optoelectronic devices, sensors, and catalysis. Finally, recent advancements in elementally doped CPDs are summarized, along with future development directions and challenges.

Post-Annealing-Induced Enhancement of Structural, Optical and Electrical Properties in Copper Tin Sulphide (CTS) Thin Films

Abstract This study investigates the impact of post-annealing on the enhancement of structural, optical and electrical properties of Copper Tin Sulfide (CTS) thin films. The CTS thin films were synthesized using the successive Ionic Layer Adsorption and Reaction (SILAR) method, then annealed at temperatures of 100°C, 200°C, and 300°C and characterized using XRD, SEM, FTIR, UV-Vis-NIR, and EDAX. The results show improved crystallinity, optical transmittance and electrical conductivity with increasing annealing temperature. The films show high bandgap energies (3.68-3.90 eV) and strong UV absorption. The transmittance curves reveal low transmittance in the UV region and high transmittance in the visible region. Post-annealing resulted in a decrease in film thickness, suggesting improved uniformity and density. An inverse relationship between crystallite size and bandgap energy was observed. These findings introduce a new paradigm for tailoring the bandgap energy and optical transmittance of CTS thin films through controlled post-annealing, enabling their application in high-performance optoelectronic devices.

Investigation of Trion Emission in CdSe/CdSeS Core/Crown Nanoplatelets.

Quasi-two-dimensional CdSe nanoplatelets (NPLs) exhibit promising potential for optoelectronic device applications due to their unique optical properties, particularly trion emission. However, the origin of the trion emission in CdSe NPLs remains unclear. In this study, the steady-state optical properties of CdSe NPLs with different CdSeS crown widths have been investigated. At low temperature, the trion emission intensity decreases with the increase of the CdSeS crown width. Using n-butylamine to remove cadmium oleate from NPLs, it is confirmed that holes in CdSe NPLs are captured by cadmium vacancies, leading to a charge imbalance and trion emission. At room temperature, thermal energy (26 meV) facilitates the escape of holes, eliminating the trion emission and shortening the fluorescence lifetime with the increase in CdSeS crown width. This work clarifies the origin of trion emission in CdSe NPLs and offers insights into the design of optoelectronic devices based on trion emission.

Multi-parameter control of photodetection in van der Waals magnet CrSBr

Photodetectors equipped with multi-parameter control hold the potential to deliver exceptional performance in a wide range of scenarios, paving the way for developing novel spin-opto-electronic devices. Nevertheless, the integration of such capabilities within a single device is challenging due to the necessity of harmonizing multiple materials with varying degrees of freedom. In this study, we introduce the van der Waals magnet CrSBr, featuring inherent anisotropy and distinctive spin-electronic coupling, to this realm. The linear dichroic ratio of the photocurrent in CrSBr tunneling device can reach ~60 at 1.65 K, and the photoresponse experiences a significant boost with increasing magnetic field. Additionally, the unique spin-charge coupling engenders a photon energy-dependent photocurrent that is modulated by an external field and is validated by first-principle calculations. Our findings elucidate the effective multi-parameter control of photodetection based on vdWs magnet CrSBr, highlighting its potential applications in cutting-edge optoelectronic devices and as a highly sensitive probe medium.

Crystal structure modulating performances for 213-nm GeO2 solar-blind photodetectors via DC reactive magnetron sputtering method

Owing to the ultra-wide bandgap energy, high thermal conductivity, and ambipolar capability, GeO2 films are receiving great attention for potential applications in power devices and solar-blind photodetectors. However, the precise control of the crystal structure and optical property is a huge challenge due to close free formation energies of multiple phases, inhibiting the GeO2 based practical device applications. Here, we have fabricated quartz and rutile-GeO2 thin films utilizing the magnetron sputtering based synthetic strategy, which exhibit ultra-wide bandgap energies of 5.51 and 5.88 eV. On the foundation of these ultra-wide bandgap semiconductors, obvious photoresponse characteristics have been achieved at 213 nm and the quartz-GeO2 device exhibits better performances including a short fall time of 148.5 ms, a high photo-dark current ratio of 86.65, large photoresponsivity of 4.56 A/W, and high detectivity of 6.78 × 1013 Jones, which can be attributed to the less oxygen defect exists in the quartz-GeO2 film due to the oxygen-rich growth condition and the better lattice matching with sapphire. Our findings suggest that the GeO2 thin film is a candidate material for optoelectronic device applications and will provide a facile and innovative strategy to develop the solar-blind photodetector.

Precise Tailoring of Unprecedent Layered Perovskite‐Type Heterostructure Ferroelectric via Chemical Molecular Scissor

AbstractPrecise stacking of distinct two‐dimensional (2D) rigid slabs to build heterostructures has renewed the portfolio of 2D materials, e.g., magic‐angle graphene, due to the emergence of exotic physical properties. Recently, single‐crystal heterostructures of layered perovskites have emerged as an exciting branch, while it remains scarce to achieve strong ferroelectricity in this new heterostructure family. Here, we present the first ferroelectric of 2D perovskite heterostructures as single crystal, (EA3Pb2Br7)EA4Pb3Br10 (1, EA=ethylamine), by precisely tailoring inorganic sheets via a chemical molecular scissor. It has notable ferroelectricity of large spontaneous polarization (Ps~5.0 μC/cm2) and high Curie temperature (Tc~375 K). Structurally, its inorganic framework adopts a unique 2D heterostructure that contains two different rigid slabs of {EA3Pb2Br7}n and {EA4Pb3Br10}n. This motif is self‐assembled by layer‐by‐layer clipping of rigid prototype sheets, using extra neopentylamine as a molecular chemical scissor. Unlike epitaxial growth, such a molecule‐level stacking facilitates the growth of heterostructure single crystals. Combining its strong ferroelectricity and inherent anisotropy, crystal‐based device of 1 exhibits an ultrahigh polarized‐light sensitivity up to ~37 in self‐powered mode, being the highest level of 2D perovskite ferroelectric family. Our work will facilitate the further development of ferroelectric materials for optoelectronic device applications.

Precise Tailoring of Unprecedent Layered Perovskite-Type Heterostructure Ferroelectric via Chemical Molecular Scissor.

Precise stacking of distinct two-dimensional (2D) rigid slabs to build heterostructures has renewed the portfolio of 2D materials, e.g., magic-angle graphene, due to the emergence of exotic physical properties. Recently, single-crystal heterostructures of layered perovskites have emerged as an exciting branch, while it remains scarce to achieve strong ferroelectricity in this new heterostructure family. Here, we present the first ferroelectric of 2D perovskite heterostructures as single crystal, (EA3Pb2Br7)EA4Pb3Br10 (1, EA=ethylamine), by precisely tailoring inorganic sheets via a chemical molecular scissor. It has notable ferroelectricity of large spontaneous polarization (Ps~5.0 μC/cm2) and high Curie temperature (Tc~375 K). Structurally, its inorganic framework adopts a unique 2D heterostructure that contains two different rigid slabs of {EA3Pb2Br7}n and {EA4Pb3Br10}n. This motif is self-assembled by layer-by-layer clipping of rigid prototype sheets, using extra neopentylamine as a molecular chemical scissor. Unlike epitaxial growth, such a molecule-level stacking facilitates the growth of heterostructure single crystals. Combining its strong ferroelectricity and inherent anisotropy, crystal-based device of 1 exhibits an ultrahigh polarized-light sensitivity up to ~37 in self-powered mode, being the highest level of 2D perovskite ferroelectric family. Our work will facilitate the further development of ferroelectric materials for optoelectronic device applications.

MAPbX3 Perovskite Single Crystals for Advanced Optoelectronic Applications: Progress, Challenges, and Perspective.

Perovskite single crystals have garnered significant attention due to their impressive properties in optoelectronic applications, including long carrier diffusion lengths, low trap-state densities, and enhanced stability. Methylamino lead halide perovskite (MAPbX3, where X is a halogen such as Cl, Br, or I) is a notable example of a metal halide perovskite with desirable properties and ideal cubic perovskites with a tolerance factor between 0.9 and 1.0. MAPbX3 has adjustable bandgap, high thermal and chemical stability, and excellent light absorption capacity. Here the unique characteristics of MAPbX3, including molecular structure, optical absorption properties, and carrier transport of MAPbX3 single crystals are summarized. Universal growth technologies for MAPbX3 single crystals, including inverse temperature crystallization, anti-solvent evaporation crystallization, solvent evaporation method, and single-crystalline thin film, including epitaxial method and space limiting method, are briefly introduced. Additionally, a comprehensive review of MAPbX3 single crystals in various optoelectronic device applications, including photodetectors, X-ray detectors, light-emitting diodes, lasers, and solar cells is mainly discussed. Finally, the current challenges and future prospects of the large-scale preparation and growth of MAPbX3 single crystals are put forward. With the continuous progress of photoelectric technology, more innovative photoelectric applications in the future are expected to bring more convenience and progress.

Deciphering the role of CIELab on emission mechanism of Samarium (Sm3+) ions embedded boro-tellurite glasses for applications in optoelectronics devices

Deciphering the role of CIELab on emission mechanism of Samarium (Sm3+) ions embedded boro-tellurite glasses for applications in optoelectronics devices

Quantum yield, energy transfer, and x-ray induced study of Sm3+ ions doped oxide glasses for intense orange-red photo-emitting optoelectronic device applications

The work elucidates detailed analysis of X-ray near edge structure of Gd3+ ions using Synchrotron studies and deciphers the energy transfer mechanism involved in the stoichiometric ratio of (79-x)B2O3 + 10ZnO + 10BaO + xGd2O3 + 1Sm2O3 (BZBGS; x = 0, 5, 10, 15, 20 mol.%) glasses. A detailed analysis of the glasses’ optical, structural, and luminescence properties were instigated to understand light emitting behaviour. The oxidation state of Gd atom inside the glass found to be + 3. Stimulated emission cross section, radiative transition probability and branching of the metastable state of rare-earth ions were evaluated using Judd-Ofelt model and compared with other reported literature. Photo-Emission spectra were monitored at the UV-C band and X-rays. Luminescence was analysed with various excitation wavelengths and sources. Photoluminescence quantum yield show more than 22 % efficiency and show more than 15 % compared with other reported glasses. Luminescence intensity ratio was analysed and found that the Sm3+-ions do not occupy the inversion-symmetry which enhances the luminescence intensity in the present glass system. The CIE and CCT values were evaluated and discussed.

Polarization-Sensitive Solar-Blind Ultraviolet Photodetectors Based on Semipolar (112̅2) AlGaN Film.

Wide bandgap semiconductor AlGaN alloys have been identified as key materials to fabricate solar-blind ultraviolet photodetectors (SBUV PDs). Herein, a self-driven SBUV polarization-sensitive PD (PSPD) based on semipolar (112̅2)-oriented AlGaN films is reported. Using the flow-rate modulation epitaxy method, the full widths at half maximum (FWHMs) for the obtained (112̅2) AlGaN along [112̅3̅] and [11̅00] rocking curves are 0.205° and 0.262°, respectively, representing the best results for heteroepitaxial semipolar AlGaN so far. Density functional theory calculations and experimental results reveal that semipolar AlGaN possesses in-plane anisotropy. The self-driven (112̅2) AlGaN PSPDs exhibit strong polarization-sensitive photoresponse with a polarization ratio of 1.54 at 266 nm and rapid response of 450/450 ms compared to other low-dimensional semiconductor materials. More interestingly, we observe positive and negative photoresponse behaviors under UV light illumination due to surface states and charge transfer. Our results may enable potential applications in multifunctional SBUV optoelectronic devices.

First-principles investigations of structural, elastic, electronic, and optical properties of silicon-doped TiO2 for photovoltaic applications

Utilising density functional theory (DFT), we conducted a comprehensive investigation into the structural, electronic, elastic, and optical properties of silicon-doped titanium dioxide (Si-doped TiO2). The structural optimisation was carried out employing the Perdew–Burke–Ernzerhof generalised gradient approximation (PBE-GGA). The calculated ground-state parameters for both pristine and silicon-doped TiO2 exhibit excellent agreement with previously reported findings, thereby affirming their validity. The stability of the compounds under investigation is substantiated by formation energy calculations, which consistently indicate negative formation energies for undoped, 3.15%, and 6.25% Si-doped TiO2, confirming their thermodynamic stability. Furthermore, the substitution of silicon atoms for titanium within the TiO2 lattice results in a discernible reduction in the band gap, quantified to be approximately 0.25 eV at lower doping levels. Theoretical simulations indicate that silicon doping significantly modifies the valence and conduction bands of TiO2, resulting in the formation of various hybrid states that enhance the mobility of photogenerated carriers. This theoretical prediction is corroborated by experimental evidence. The enhanced optical properties of the investigated compounds render them highly suitable for applications in optoelectronic devices.

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.

Mangifera indica–driven CuO nanoparticles: properties for sensing and optoelectronics

This study reports biological synthesis of Mangifera indica leaf extract–mediated copper oxide nanoparticles (CuO NPs). CuO NPs are characterized for crystal structure and crystallite size determination, absorption peak, particle size and morphological analysis, elemental composition, and functional groups’ identification using X-ray diffraction (XRD), ultraviolet–visible spectroscopy, high-resolution transmission electron microscope (HRTEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), and Fourier transform infrared (FTIR). NPs show an absorption peak ∼338 nm and Tauc’s plot gives band gap energy ∼2.2 eV. XRD pattern depicts monoclinic phase ∼18 nm average crystallite size NPs. FESEM and HRTEM micrographs confirm the needle-shaped NPs having 5:40 nm aspect ratio. The EDS spectrum, depicting the Cu and O peaks, shows that the particles are free from any type of impurity. FTIR analysis elucidates the role of bioactive chemicals in the extract in the successful formation of NPs. The photoluminescence study reveals the existence of violet, green, orange, yellow, and red emission bands. Also, NPs exhibit an electrical conductivity of 1.37 × 10–7 S/m and 5. 31 × 10–7 S/m at 100°C and 200°C. Thus, environmentally friendly, non-toxic, green-synthesized CuO NPs hold significant potential for applications in resistive sensors, solar cells, and optoelectronics devices.

Progress in in situ TEM investigations of halide perovskites

Halide perovskites (HPs) have found wide-ranging applications in photovoltaic and optoelectronic devices, achieving remarkable success due to their unique crystal structure and properties. Given the sensitivity of perovskite materials to external stimuli, it is crucial to understand the intrinsic changes in structure and chemical composition during operational conditions. This understanding could assist researchers in exploring new strategies to enhance the photoelectrical properties and stability of these materials. While many in situ methods, such as in situ X-ray diffraction and in situ photoluminescence, have been employed to investigate the properties of perovskite materials in real-time, in situ transmission electron microscopy (TEM) stands out as an unparalleled technique for observing subtle changes at the micro and even atomic scale. In this review, we summarize recent advancements in studying HPs using in situ TEM. We first introduce studies on the crystallization process of HP crystals through in situ TEM observation, and then categorize research works on the degradation process of HPs driven by different external stimuli, including electron beam, heat, electrical bias, light, and ambient atmosphere. Finally, we highlight several challenges that still need to be addressed in the future. This review aims to present a thorough summary of the existing research and lay the groundwork for future inquiries in this captivating area.

Detailed structural study, optical, and dielectric properties of Co0.4Ni0.3Zn0.3Fe2O4 ferrite and its potential applications for optoelectronic and electronic devices

Detailed structural study, optical, and dielectric properties of Co0.4Ni0.3Zn0.3Fe2O4 ferrite and its potential applications for optoelectronic and electronic devices

Optical properties of quasi-two-dimensional GaAs/AlGaAs nanosheets prepared by releasing epitaxial layer.

Quasi-two-dimensional nanosheets exhibit novel properties and promising applications in optoelectronic flexible devices. Research on non-layered III-V semiconductor nanosheets has been constrained by their covalent bonding connections. In this study, GaAs/AlGaAs heterojunction nanosheets were prepared by releasing an epitaxial layer, and their optical properties were investigated by adopting steady-state and transient absorption spectroscopy. The optical properties of the independent GaAs/AlGaAs heterojunction were investigated separately in order to exclude the effect of the substrate. This work provides a comprehensive understanding of the physics of III-V semiconductor quasi-two-dimensional nanosheets.&#xD.

Comparative Optical Properties of Amorphous and Crystalline MoO3 Films by Spectroscopic Ellipsometry Study

This paper presents a comprehensive study of the optical properties of amorphous and crystalline MoO3 thin films using spectroscopic ellipsometry. MoO3 films were deposited on SiO2/Si substrates with varying oxide thicknesses using the atomic layer deposition (ALD) method. The study utilized various optical oscillator models, including Lorentz, Tauc–Lorentz and Harmonic, to analyze the dielectric functions and identify midgap states resulting from oxygen deficiencies. The findings highlight significant differences in the optical properties between amorphous and crystalline MoO3 films, demonstrating the impact of structural phases and substrate conditions. Specifically, amorphous films exhibited lower broadening and energy peaks compared to crystalline films, which showed distinct midgap states indicative of higher oxygen vacancy concentrations. These results enhance the understanding of the optical behavior of MoO3 films and their potential applications in advanced optoelectronic devices.

2D MXenes: Synthesis, Properties, and Applications in Silicon-Based Optoelectronic Devices.

MXenes, a rapidly emerging class of 2D transition metal carbides, nitrides, and carbonitrides, have attracted significant attention for their outstanding properties, including high electrical conductivity, tunable work function, and solution processability. These characteristics have made MXenes highly versatile and widely adopted in the next generation of optoelectronic devices, such as perovskite and organic solar cells. However, their integration into silicon-based optoelectronic devices remains relatively underexplored, despite silicon's dominance in the semiconductor industry. In this review, a timely summary of the recent progress in utilizing Ti-based MXenes, particularly Ti3C2Tx, in silicon-based optoelectronic devices is provided. The composition, synthesis methods, and key properties of MXenes that contribute to their potential for enhanced device performance are focused on. Furthermore, the latest advancements in MXene applications in silicon-based solar cells and photodetectors are discussed from fundamental and applied perspectives. Finally, the key challenges and future opportunities for the integration of MXenes in silicon-based optoelectronic devices are outlined.

Effect of Ti Doping on the Structural, Electronic, Optical and Thermoelectric Properties of ZrO2: A Systematic DFT Approach

AbstractIn this work, the density functional theory (DFT) calculations in wien2k code to investigate the effect of (Titanium) Ti doping (25% and 50%) in ZrO2 is utilized. The negative values of the Ef, i.e., −2.14, −3.42 and −2.31 as well as energy versus volume curves show the stability of pure, 25% and 50% doped ZrO2. From band structure and density of states results it is confirmed that upon doping Ti, the band gap of ZrO2 become direct from indirect and reduces from 3.10 eV to 1.26(25% doped)/1.16(50% doped). The optical investigations reveal that incorporation of Ti improved the optical properties significantly, which show the significance of these materials for optoelectronic device applications. The thermoelectric properties are investigated using the Boltzmann transport theory. The Seebeck coefficient, electronic conductivity, thermal conductivity, power factor and figure of merit is calculated. The obtained results show that the under study compounds are best candidates for different thermoelectric applications.