Advanced Optoelectronic Devices Research Articles

Tunable Electronic Properties, Carrier Mobility, and Contact Characteristics in Type-II BSe/Sc2CF2 Heterostructures toward Next-Generation Optoelectronic Devices.

Conducting heterostructures have emerged as a promising strategy to enhance physical properties and unlock the potential application of such materials. Herein, we conduct and investigate the electronic and transport properties of the BSe/Sc2CF2 heterostructure using first-principles calculations. The BSe/Sc2CF2 heterostructure is structurally and thermodynamically stable, indicating that it can be feasible for further experiments. The BSe/Sc2CF2 heterostructure exhibits a semiconducting behavior with an indirect band gap and possesses type-II band alignment. This unique alignment promotes efficient charge separation, making it highly promising for device applications, including solar cells and photodetectors. Furthermore, type-II band alignment in the BSe/Sc2CF2 heterostructure leads to a reduced band gap compared to the individual BSe and Sc2CF2 monolayers, leading to enhanced charge carrier mobility and light absorption. Additionally, the generation of the BSe/Sc2CF2 heterostructure enhances the transport properties of the BSe and Sc2CF2 monolayers. The electric fields and strains can modify the electronic properties, thus expanding the potential application possibilities. Both the electric fields and strains can tune the band gap and lead to the type-II to type-I conversion in the BSe/Sc2CF2 heterostructure. These findings shed light on the versatile nature of the BSe/Sc2CF2 heterostructure and its potential for advanced nanoelectronic and optoelectronic devices.

A Combined Theoretical and Experimental Investigation of 3D Ternary Perovskite‐Like Silver Iodobismuthate

AbstractLead‐free ternary bismuth halide perovskites A3Bi2X9 have gained much attention as a solution for toxic and unstable lead halide perovskites due to their facile solution processability, high optical absorption coefficient, and high stability. However, their photovoltaic performance remains poor due to their wide bandgap (∼2 eV), and poor charge transport properties stem from their low‐dimensional crystal structure. To promote the 3D structure and reduce the bandgap of ternary Bi‐halide perovskites, we replace the alkali elements at the A‐site with the transition element Ag+ to obtain a new class of perovskite‐like materials named rudorffites AgaBibIa+3b. We investigated the photophysical properties of AgBiI4 by a combined theoretical and experimental approach. Our DFT‐PBE‐SOC predicted band gap for cubic defect spinel AgBiI4 is 2.01 eV, while that obtained for spin‐coated AgBiI4 film is 1.67 eV. Furthermore, the strong p‐p band edge transition leads to high optical absorption in this material. Finally, a photodetector device fabricated using AgBiI4 shows excellent photoresponsivity (183 μA/W) and detectivity (20.93×108 Jones) with a fast rise/decay time of 0.27 s/0.29 s. This newly explored semiconductor class can be a promising and stable choice for advanced optoelectronic devices.

Large-scale and stacked transfer of bilayers MoS2 devices on a flexible polyimide substrate

Two-dimensional transition metal dichalcogenides (TMDs), as flexible and stretchable materials, have attracted considerable attention in the field of novel flexible electronics due to their excellent mechanical, optical, and electronic properties. Among the various TMD materials, atomically thin MoS2 has become the most widely used material due to its advantageous properties, such as its adjustable bandgap, excellent performance, and ease of preparation. In this work, we demonstrated the practicality of a stacked wafer-scale two-layer MoS2 film obtained by transferring multiple single-layer films grown using chemical vapor deposition. The MoS2 field-effect transistor cell had a top-gated device structure with a (PI) film as the substrate, which exhibited a high on/off ratio (108), large average mobility (∼8.56 cm2 V−1 s−1), and exceptional uniformity. Furthermore, a range of flexible integrated logic devices, including inverters, NOR gates, and NAND gates, were successfully implemented via traditional lithography. These results highlight the immense potential of TMD materials, particularly MoS2, in enabling advanced flexible electronic and optoelectronic devices, which pave the way for transformative applications in future-generation electronics.

Engineering anisotropy in 2D transition metal dichalcogenides via heterostructures.

Two-dimensional (2D) semiconductors featuring low-symmetry crystal structures hold an immense potential for the design of advanced optoelectronic devices, leveraging their inherent anisotropic attributes. While the synthesis techniques for transition metal dichalcogenides (TMDs) have matured, a promising avenue emerges: the induction of anisotropy within symmetric TMDs through interlayer van der Waals coupling engineering. Here, we unveil the creation of heterostructures (HSs) by stacking highly symmetric MoSe2 with low-symmetry ReS2, introducing artificial anisotropy into monolayer MoSe2. Through a meticulous analysis of angle-dependent photoluminescence (PL) spectra, we discern a remarkable anisotropic intensity ratio of approximately 1.34. Bolstering this observation, the angle-resolved Raman spectra provide unequivocal validation of the anisotropic optical properties inherent to MoSe2. This intriguing behavior can be attributed to the in-plane polarization of MoSe2, incited by the deliberate disruption of lattice symmetry within the monolayer MoSe2 structure. Collectively, our findings furnish a conceptual blueprint for engineering both isotropic and anisotropic HSs, thereby unlocking an expansive spectrum of applications in the realm of high-performance optoelectronic devices.

Enhancing photoluminescence properties of Mn2+ doped CsPbCl3 nanocrystals via alkaline-earth Co-doping

Doping Mn2+ into CsPbCl3 nanocrystals (NCs) has garnered significant attention for its potential to create tailored optical properties in optoelectronic applications. However, this approach still faces challenges, including low photoluminescence quantum yield (PL QY), suboptimal Mn2+ doping efficiency, and inadequate stability. Herein, we delve into the specific realm of Mn2+ doping in CsPbCl3 NCs and delve into the effects of co-doping these NCs with alkaline earth (AE2+) metal ions. Through a comprehensive characterization of the co-doped NCs, we systematically unravel bonding characteristics, and luminescence behaviors induced by AE2+ co-doping. The outcomes underscore the notable enhancement in luminescence performance and stability achieved through AE2+ co-doping, particularly with Sr2+. The utilization of smaller AE2+ results in lattice contraction, leading to improved PL QY and heightened photostability. This work offers valuable insights into tailoring the performance of transition metal-doped semiconductor NCs for advanced optoelectronic devices, establishing a foundation for subsequent optimization and diverse applications.

N-type organic phototransistors based on PTCDA single crystals for broadband imaging

Organic single crystals (OSCs) herald new opportunities for the fabrication of advanced optoelectronic devices, especially for flexible and wearable devices, owing to their unique material properties including high mobility and intrinsic flexibility. Up to now, though the electrical characteristics have been a breakthrough in OSCs, the devices have not been fully optimized for inherent photoelectric properties, and their photoresponse characteristics are also scarcely satisfactory, especially for the n-type organic materials. In this work, we prepared a high-performance organic phototransistor employing the air-stable PTCDA single crystal, grown by a simple microspacing in-air sublimation technique. The responsivity and photosensitivity of the device can reach up to 180 A/W and 103 for 532 nm illumination, with also a good response speed (rise and decay times less than 1 and 2 ms). In addition, we demonstrated several high-resolution imaging in this organic transistor. Our results demonstrated that the high-quality n-type organic single crystal is also a promising candidate for future high-performance photodetector and imaging applications.

Large‐Scale Perovskite Single Crystal Growth and Surface Patterning Technologies

In the past decade, metal halide perovskite polycrystalline films have witnessed significant advancements in the field of high‐performance optoelectronic devices, including photodetectors, solar cells, light‐emitting diodes, and lasers. Perovskite films with periodic micro/nanoarrays have garnered substantial attention due to their capability not only to improve the efficiency of individual devices but also to hold great promise for future commercialization. Surpassing their polycrystalline counterparts, perovskite single crystals typically exhibit longer carrier diffusion lengths, extended carrier lifetimes, and enhanced carrier mobility due to the absence of grain boundaries and reduced defects, positioning them as promising candidates for both fundamental studies and advanced optoelectronic devices. To this end, significant endeavors have been dedicated to the development of diverse methodologies for synthesizing large‐scale perovskite single crystals, including bulk single crystals and single‐crystal thin films. Furthermore, aiming to integrate the distinctive functionality with single crystals, considerable efforts have been directed toward the design of certain patterns on single‐crystal surfaces. Herein, this review presents recent progress in technologies for the preparation of large‐scale single crystals and the approaches to patterning their surfaces, highlights the unique advantages of each method, and presents their promising advances in various optoelectronic applications as well as the potential challenges.

Exploring A‐Site Cation Variations in Dion–Jacobson Two‐Dimensional Halide Perovskites for Enhanced Solar Cell Applications: A Density Functional Theory Study

The exceptional photophysical and electronic properties of 2D hybrid perovskites possess potential applications in the field of solar energy harvesting. The present work focuses on the two systems, exhibiting the Dion–Jacobson phase of 2D perovskite consisting of methylammonium (MA) and formamidinium (FA) cations at A‐site and 3‐(aminomethyl)pyridinium (3AMPY) as ring‐shaped organic spacer. Altering A‐site cations creates a distortion of inorganic layers and hydrogen bond interactions. It has been noted that the angles of Pb–I–Pb and I–Pb–I are more symmetric (close to 180°) for (3AMPY)(MA)Pb2I7 compared to (3AMPY)(FA)Pb2I7 and result in increase of bandgap from 1.51 to 1.58 eV. This further leads to a significant difference in Rashba splitting energy under the influence of spin‐orbit coupling effects, where the highest splitting (36 meV) is calculated for conduction band edge of the (3AMPY)(FA)Pb2I7, suggesting the promising applications toward spintronics. The calculated absorption spectra cover the range from 300 to 450 nm, indicating significant optical activity of 2D (3AMPY)(MA)Pb2I7 and (3AMPY)(FA)Pb2I7 in the visible and ultraviolet regions, which bodes well for their application in advanced optoelectronic devices. The bandgap and high absorption coefficients present more than 30% of theoretical power conversion efficiency for both systems, as calculated from the spectroscopic‐limited maximum efficiency.

Halide Ordering Enables Superior Charge Transport in 3D (NMPDA)Pb2 I4 Br2 Perovskitoid Single Crystal.

Halide composition engineering has been demonstrated as an effective strategy for optical and electronic properties modulation in 3D perovskites. While the impact of halide mixing on the structural and charge transport properties of 3D perovskitoids remains largely unexplored. Herein, it is demonstrated that bromine (Br) mixing in 3D (NMPDA)Pb2 I6 (NMPDA = N-methyl-1,3-propane diammonium) perovskitoid yields stabilized (NMPDA)Pb2 I4 Br2 with specific ordered halide sites, where Br ions locate at the edge-sharing sites. The halide ordered structure enables stronger H-bonds, shorter interlayer distance, and lower octahedra distortion in (NMPDA)Pb2 I4 Br2 with respect to the pristine (NMPDA)Pb2 I6 . These attributes further result in high ion migration activation energy, low defect states density, and enhanced carrier mobility-lifetime product (µτ), as underpinned by the electrical properties investigation and DFT calculations. Remarkably, the parallel configured photodetector based on (NMPDA)Pb2 I4 Br2 single crystal delivers a high on/off current ratio of 3.92×103 , a satisfying photoresponsivity and detectivity of 0.28 AW-1 and 3.05×1012 Jones under 10.94 µWcm-2 irradiation, superior to that of (NMPDA)Pb2 I6 and the reported 3D perovskitoids. This work sheds novel insight on exploring 3D mixed halide perovskitoids toward advanced and stable optoelectronic devices.

Well-ordered molecular heterojunction of epitaxial C60 on single-crystal dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT)

A well-ordered molecular arrangement is a necessary condition for “band transport” in molecular semiconductor materials, and thus it is important for donor–acceptor molecular junctions for applications in advanced organic optoelectronic devices. In this study, the heteroepitaxial growth of an acceptor material C60 on a single-crystal (001) surface of dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT), a representative high-mobility donor material, is demonstrated. Surface X-ray diffraction analysis indicated spontaneous alignment of the nearest-neighbor molecular direction of the C60 crystallites uniquely to the a -axis of the DNTT.

Engineering and Controlling Perovskite Emissions via Optical Quasi‐Bound‐States‐in‐the‐Continuum

AbstractMetal halide perovskite quantum dots (PQDs) have emerged as promising materials due to their exceptional photoluminescence (PL) properties. A wide range of applications could benefit from adjustable luminescence properties, while preserving the physical and chemical properties of the PQDs. Therefore, post‐synthesis engineering has gained attention recently, involving the use of ion‐exchange or external stimuli, such as extreme pressure, magnetic and electric fields. Nevertheless, these methods typically suffer from spectrum broadening, intensity quenching or yield multiple bands. Alternatively, photonic antennas can modify the radiative decay channel of perovskites via the Purcell effect, with the largest wavelength shift being 8 nm to date, at an expense of fivefold intensity loss. Here, this work presents an optical nanoantenna array with polarization‐controlled quasi‐bound‐states‐in‐the‐continuum resonances, which can engineer and shift the photoluminescence wavelength over a ≈39 nm range and confers a 21‐fold emission enhancement of FAPbI3 perovskite QDs. The spectrum is engineered in a non‐invasive manner via lithographically defined antennas and the pump laser polarization at ambient conditions. This research provides a path toward advanced optoelectronic devices, such as spectrally tailored quantum emitters and lasers.

Cerium-modified Bi2FeMoO6: Microstructure, dielectric and optical properties

This paper presents an extensive investigation into the synthesis and characterization of Bi2FeMo1-xCexO6 (x = 0.0, 0.06, and 0.1) double perovskite type ceramic materials, fabricated using a high-temperature solid-state reaction method. The article delves into various aspects of these materials, including their structural, microstructural, dielectric, and optical properties. Structurally, the materials exhibit a rhombohedral crystal structure, having average crystallite sizes of 49.5 nm, 21.8 nm, and 26.4 nm for the respective compositions. Scanning electron microscopy reveals a uniform distribution of cylindrical and fractured spherical-shaped grains, complemented by well-defined grain boundaries. Energy dispersive X-ray spectroscopy analysis and elemental color mapping provide concrete evidence regarding the presence of key elements, such as Bi, Fe, Mo, Ce, and O, affirming the formation of highly dense and pure samples. Dielectric properties are comprehensively characterized across a wide temperature range of 25 °C to 500 °C and frequency range of 1 kHz to 1 MHz, highlighting the occurrence of the Maxwell-Wagner polarization effect at lower frequencies. The impedance study underscores the pivotal role of both grains and grain boundaries in determining the conductivity mechanism, with the x = 0.1 composition exhibiting superior semiconducting characteristics. Further examination of the modulus study and AC conductivity supports this finding. Additionally, the calculation of thermal activation energy suggests that the x = 0.1 composition boasts a more favorable thermally activated relaxation mechanism, rendering it a promising candidate for various device applications. Finally, an assessment of the UV–visible spectra reveals that the x = 0.1 composition possesses an ideal bandgap energy range, making it particularly suited for advanced optoelectronic devices.

Determination of bandgap of period 3, 4, and 5 transition metal dopants on zinc oxide using an artificial neural network based approach

Artificial intelligence (AI) and machine learning (ML) have rapidly emerged as valuable tools for chemical research, offering new ways to analyze and understand complex chemical systems. This research article investigates the use of adaptive neuro-fuzzy inference system (ANFIS) and multi-layer perceptron (MLP) models to predict the bandgap of transition metal doped zinc oxide (ZnO). The opto-electronic properties of transition metal doped ZnO complexes are of significant interest because of their applications is optoelectronic systems. The MLP and ANFIS models were trained using a dataset of experimentally measured bandgap values and the corresponding structural parameters of the doped ZnO systems. The performance of the models was evaluated using statistical metrics i.e., RMSE, R, and MAE. The results showed that both MLP and ANFIS models were capable of accurately predicting the bandgap of transition metal doped ZnO. However, the ANFIS model demonstrated superior performance with higher accuracy and better generalization ability. The study provides a useful approach for predicting the bandgap of transition metal doped ZnO using machine learning techniques and may contribute to the development of advanced optoelectronic devices.

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.

Fine-Tuning of the Electronic and Optical Properties of Dodecabenzocoronene through Boron and Nitrogen Doping: A DFT Insight

Nanographene provides a wide range of possibilities in graphene engineering for future applications due to the higher degrees of configurational freedom with the electronic parameters that may also be continuous or discrete, depending on the intended application. Therefore, the optical and electronic properties of nanographene are of substantial technological interest. Moreover, doping of graphene with heteroatoms (B, P, N, and S, etc.) alters their chemical and electronic characteristics which are suitable for the economical construction of optoelectronic devices. Herein, geometric, electronic, and optical properties of nanographene are evaluated as a function of the nature and position of dopant. Three different nanographene including coronene, hexabenzocoronene (HBC), and dodecabenzocoronene (DBC) are considered for doping (N and B as dopants) in this study with the key focus on DBC-doped systems. For any dopant number, all possible dopant sites are studied except edge position in order to avoid the edge effect. Frontier molecular orbital (FMO) analysis is performed to evaluate the perturbations in electronic characteristics of doped nanographene. A decrease in energy gap is seen for all doped systems. Natural bond orbital (NBO) analysis indicates that doping of boron (B) and nitrogen (N) results in variation in distribution of charges over the nanographene surfaces. The density of states (DOS) analysis reveals that Fermi level ([Formula: see text] is shifted for all B- and N-doped systems. The UV-visible (UV-Vis) absorption spectra are computed to evaluate the changes in the intensity and maximum adsorption wavelength ([Formula: see text] in all doped DBC. Various chemical reactivity descriptors are also evaluated which reveal the degree of stability and chemical reactivity of doped systems. The results indicate that multiple B and N atoms doping offers a new possibility for fine-tuning of electronic and optical properties of nanographene at atomic level, thus providing guidance in development of future advanced optoelectronic devices.

Insights into the structural and optical features of plasma polymerized N, N, 3, 5 tetramethylaniline-2,6-diethylaniline thin films

A capacitively coupled AC (50 Hz) glow plasma has been used to produce plasma polymerized N, N, 3, 5 tetramethylaniline: 2,6-Diethylaniline composite thin films onto precleaned glass substrates at various monomer ratios. The FSEM studies revealed smooth, compact, flawless, and pinhole-free surfaces of the thin films. The energy-dispersive X-ray spectrum confirmed the existence of carbon, nitrogen, and oxygen in the composite thin films. The broadband weak absorption peaks in the FTIR spectra indicated the structural modifications in the plasma polymer caused by the reorganization of two monomer molecules during the plasma polymerization process. The thickness of the composite film increased with rising N, N, 3, 5 tetramethylaniline percentage in the composition, which had an important effect on the optical properties while keeping the polymerization parameter the same for all the deposited films. Decreasing the proportion of N, N, 3, 5 tetramethylaniline monomer results in an increase in both direct and indirect optical band-gap values, from 2.84 to 2.94 eV and 1.74–1.87 eV, respectively. While the Urbach energy values decrease from 0.649 eV to 0.556 eV. From the optical absorbance curve, it was observed that with increasing N, N, 3, 5 tetramethylaniline monomer concentration, the absorbance increased and reached a maximum at this monomer concentration of 75%. We also measured the non-linear optical parameters-steepness parameter, refractive index, extinction coefficient, and dissipation factor to understand the suitability of the composite thin films for advanced optoelectronic devices.

Preface to Special Issue on Advanced Optoelectronic and Electronic Devices toward Future Displays

Preface to Special Issue on Advanced Optoelectronic and Electronic Devices toward Future Displays

Comparative analysis of the structural, optical, mechanical, and electrical properties of PMMA/PU blend‐based nanocomposites with FeVO4 nanofiller for energy storage devices

AbstractThe best materials for enhanced energy storage capacitors in electrical systems are polymer nanocomposites films. Therefore, using the solution casting approach, we created a unique series of FeVO4 nanofiller‐embedded polyurethane (PU) and polymethyl methacrylate (PMMA)‐based composites. Various techniques were used to describe the prepared films. XRD spectra were used to assess the crystallinity and crystallite size of nanocomposites. The XRD spectra were used to assess the crystallinity and crystallite size of nanocomposites. With rising nanoparticles (NPs) content up to samples with 1.5 weight percent of FeVO4, XRD demonstrated an increase in the amorphous phase of the polymer mixture, which was further supported by UV–Vis measurements. FTIR was used for determining the complexation of the FeVO4 with the polymer mixture. Calculations were used to determine optical properties such as the Urbach energy and energy bandgap. With a rise in FeVO4 NP concentration, the energy bandgap decreases while the Urbach energy increases. All samples' AC conductivity spectra exhibit Jonscher's power law (JPL) behavior. Studies on dielectric permittivity and electric modulus have also been conducted in order to comprehend the charge storage characteristics and conductivity relaxation. Whereas the frequency‐dependent increase in AC electrical conductivity, the ε′ and ε″ of PU/PMMA–FeVO4 nanocomposites drop with the rising of the electric field frequency. The high level of FeVO4 was shown to improve the AC conductivity, ε′ and ε″ values of the nanocomposites. Tensile strength was improved by 38% with the addition of FeVO4 NPs into the PU/PMMA blend. Experimental outcomes show that these polymer nanocomposites materials are multifunctional and can be used as low‐permittivity nanodielectric insulators and substrates to design the next generation of flexible electronic devices and also there can be used to create a variety of advanced optoelectronic and organic electronic devices.

GaAs/GaInNAs core-multishell nanowires with a triple quantum-well structure emitting in the telecommunication range

Semiconducting nanowires (NWs) fabricated from III–V materials have gained significant attention for their application in advanced optoelectronic devices. Here, the growth of GaAs/GaInNAs/GaAs core-multishell NWs with a triple quantum-well structure, having about 2% N and 20% In, is reported. The NWs are grown via selective area plasma-assisted molecular beam epitaxy on patterned Si(111) substrates with SiO2 mask holes. The nucleation and growth of the GaAs nanowires' core are carried out by Ga-induced vapor–liquid–solid growth at the open holes. Finely controlled, vertically aligned, regular core-multishell NWs with uniform wire length and diameter are obtained with a 96% yield and targeted nitrogen concentrations of 0%, 2%, and 3%. The GaInNAs NWs exhibit a spectral red shift relative to the GaAs NWs' peak. Their emission wavelength increases with the N content reaching up to 1.26 μm, which makes them a promising tool in telecommunication light sources.

Accurate Dimension Prediction for Low-Dimensional Organic-Inorganic Halide Perovskites via a Self-Established Machine Learning Strategy.

Low-dimensional perovskites (LDPs) have enormous potential for the development of advanced optoelectronic devices and tackling the stability issue for the commercial application of perovskites. However, quantified structural dimensionality prediction for LDPs is still an intractable issue. Herein, we develop a self-established machine learning (ML)-assisted approach to predict the dimensionality of LDPs based on 195 reported amines that are classified as two-dimensional, one-dimensional, and zero-dimensional. The optimal K-nearest neighbor model allows us to realize an accuracy rate of 92.3% for the test data set containing 39 reported amines. Two features, i.e., ATSC1pe and SlogP_VSA2, associated with polarity and electrostatic potential on the van der Waals surface of an organic spacer, are identified from >1800 descriptors as key controlling factors determining the structure dimensionality. This work develops a typical paradigm for the application of a multiple-classification strategy of ML with an extremely high accuracy rate, which would thereby motivate the development of new types of LDPs.