Colloidal quantum dot (QD) solid-state films are fundamental building blocks for modern optoelectronic devices. In these films, the complex dielectric environment formed by surrounding QDs and organic ligands significantly modifies their electronic and excitonic properties, posing a considerable theoretical challenge. Herein, we report a robust first-principles scheme capable of accurately predicting the fundamental and optical gaps of these films. The methodology's success is rooted in a twofold innovation: the development of optimized, dimensionally consistent Gaussian basis sets that accurately treat both extended and confined systems, and a unique density functional parameterization. This parameterization employs screened range-separated hybrid density functional theory, uniquely incorporating the QD size-dependence of the range-separation parameter while introducing the solid-state film's scalar dielectric constant. This comprehensive scheme determines the electronic structure with an accuracy competing with state-of-the-art self-consistent GW calculations. Applying it to group IV and II-VI QD solid-state films, we achieve an excellent reproduction of experimental fundamental and optical gaps, allowing the accurate determination of the exciton binding energy. We established that this binding energy in solid-state films scales linearly with the inverse QD diameter, a key relationship predicted by classical electrostatics that is largely independent of the material type. Conventional hybrid functional calculations are found to severely fail to quantify this energy and its size-dependent scaling relations. This work provides a cost-effective and broadly applicable theoretical framework for accurately determining the electronic and optical properties of colloidal QD solid-state films.

Correction for ‘Decoupling thermoelectric parameters in novel ionic layered materials: a charged monolayer stabilization strategy for enhanced anisotropy’ by Yaobo Li et al. , Mater. Horiz. , 2026, https://doi.org/10.1039/D5MH02247A.

Liquid crystals (LC) are widely used in various optical devices due to their birefringence, dielectric anisotropy, and responsive behavior to external fields. Enhancing the properties of existing LCs through doping with nanoparticles, including semiconductor quantum dots, offers a promising route for improving their performance. Among various nanoparticles, QDs stand out for their high charge mobility, sensitivity in the near-infrared spectral region, and cost-effectiveness. These attributes make them ideal candidates for integration with LCs. While liquid crystalline behavior arises from the collective ordering of molecules, the microscopic interactions between QDs and LC molecules remain an intriguing area of study to understand the underlying quantum-level mechanisms. In this study, we employ Density Functional Theory to investigate the interaction between GaAs quantum dot and a 5CB molecule. The 5CB molecule and Ga atoms were brought together gradually, and the corresponding changes in interaction energy and electron density distributions were calculated. The energy profiles reveal a clear distance-dependent interaction, with a minimum observed at 2.1 Å, indicating the formation of stable complexes. While the BVP86 functional slightly overestimated the interaction energy, the B3LYP functional produced more accurate results, confirming the feasibility of stable quantum dot - 5CB molecule complexes.

In this study, we investigate the nonlinear optical rectification (NOR) in GaAs/AlGaAs Conical Core/Shell Quantum Dots under varying temperature conditions, utilizing compact density matrix formalism. The energy levels and wave functions are computed by solving the Schrodinger equation with the Finite Element Method (FEM) within the framework of the effective mass approximation (EMA). The objective of the present study is to develop an accurate and efficient method for modelling and predicting the NOR coefficient, taking into account the influence of pressure effect on the quantum dot system. To achieve this, we apply a range of machine learning algorithms, specifically, four ML models were studied; Artificial Neural Networks (ANN), Decision Trees (DT), Gradient Boosting (GB) and Recurrent Neural Networks (RNN). Among these, the Decision Tree model exhibits exceptional prediction performance, achieving R2 = 0.9984, MSE = 10-3, and MAE = 9.1 x 10-3 at a fixed value of the pressure at 20 kbar. The importance of this work lies in its potential to provide valuable insights for neither designing advanced quantum dot-based optoelectronic devices, such as infrared detectors and photonic components, where temperature-dependent NOR are properties crucial for performance optimization. Furthermore, the application of machine learning techniques in this context offers a promising approach for efficient and accurate modelling of complex quantum systems, facilitating the development of future quantum technologies.

In this study, we investigate the nonlinear optical rectification (NOR) between the first and excited states in GaAs/AlGaAs Tetrapod Core/Shell Quantum Dots (TCSQDs) under the effect of temperature, using the compact density matrix formalism. The energy levels and wave functions are computed by solving the Schrodinger equation with the Finite Element Method (FEM) within the framework of the effective mass approximation (EMA). The objective of the present study is to develop an accurate and efficient method for modelling and predicting the NOR coefficient related to E23 transition, taking into account the influence of temperature variations on the quantum dot system. To achieve this, we apply a range of machine learning (ML) algorithms, including Artificial Neural Networks (ANN), Decision Tree (DT), and Random Forest Regression (RFR). Among these, Random Forest Regression yields the best performance, achieving R2 = 0.99940, MSE = 1.10 x 10-4, and MAE = 0.00510 at room temperature. The importance of this work lies in its potential to provide valuable insights for neither designing advanced quantum dot-based optoelectronic devices, such as infrared detectors and photonic components, where temperature-dependent NOR are properties crucial for performance optimization. Furthermore, the application of ML techniques in this context offers a promising approach for efficient and accurate modelling of complex quantum systems, facilitating the development of future quantum technologies.

Vacuum Fourier spectrometer was used to obtain mid-infrared photoinduced absorption spectra of undoped GeSi/Si quantum dots at liquid helium temperature under different conditions of interband optical pumping. High-intensity peaks in the absorption spectra are associated with intraband hole transitions from the ground and excited states of the quantum dot to the continuous spectrum. The less intense long-wavelength peak corresponds to the hole transitions between the ground and excited states. In the terahertz spectral range, equilibrium absorption spectra were obtained, associated with transitions from the ground to a nearby excited state of holes. Structures with GeSi/Si quantum dots can be used to develop detectors of mid-infrared radiation.

The physical chemistry of surface phenomena in polymers is an important issue when studying the interaction of polymers with solid surfaces. This is due to the fact that most of the modern polymer materials are heterogeneous systems with highly developed phase separation surfaces. An example of such materials can be reinforced plastic, filled thermoplastics, reinforced rubber, paint coatings, etc. Polymer adsorption at the boundary of the phase separation process in solids plays an important role in the reinforcing effect of fillers, adhesion, gluing and obtaining composite materials with high strength properties. Compositions based on polyvinyl alcohol (PVA) modified with carbon nanotubes (CNTs) can be used as an interesting and informative system for studying the structure and properties of polymer nanocomposites, especially in a highly oriented state. PVA has one of the simplest chemical structure among the polymers, containing a functional (hydroxyl) group capable of participating in interphase interactions. In turn, carbon nanotubes with unique strength properties are currently products of industrial production, which makes it possible to control and modify their properties. To prove the possibility of creating new composite materials with improved strength characteristics, the mechanisms of interaction between PVA and CNTs are studied by modeling the adsorption processes of a polymer fragment on the outer surface of single-layer carbon nanotubes of different chirality, performed within the framework of the modern DFT calculation method. The main adsorption characteristics of the process and the features of the electron energy structure of the resulting composite systems are determined.

The results of comprehensive studies of near-infrared photoluminescence and mid-infrared equilibrium and photoinduced absorption spectra in structures with Ge/Si quantum dots with different doping levels at different optical pumping intensities and different temperatures are presented. Obtained dependences of interband photoluminescence spectra on temperature and optical pumping intensity are explained by the change in the intensities of direct and indirect in real space electron-hole recombination in Ge/Si quantum dots. The spectra of equilibrium and photoinduced absorption of polarized mid-infrared radiation demonstrate peaks associated with transitions of holes from the ground and excited states to continuum states above quantum dots and with optical transitions from the ground states to excited ones.

The current study uses various computational methods to determine the eigenvalues and eigenvectors of a specific system—namely, a two-impurity, two-electron system within a dumbbell-shaped quantum dot. Initially, the single-electron, single-impurity problem is resolved using the effective mass approximation and the finite element method. Subsequently, a technique similar to the linear combination of atomic orbitals is applied to derive singlet–triplet states. The research work deeply investigates the key characteristics of the mentioned states, with a particular focus on their energy splitting and exchange times. Additionally, it highlights the dynamic evolution of the singlet–triplet two-level system, illustrating its manipulation through detuning and Rabi frequency. The Mollow triplet spectrum is also calculated and analyzed under various initial conditions. The findings of this research have significant implications across multiple domains, including the advancement of quantum information processing, the enhancement of optoelectronic device performance, and the development of innovative sensing and communication technologies.

The study investigates and compares the impact of intense, non-diffractive, non-resonant structured laser beams with various intensity profiles on the properties of InAs/GaAs cylindrical quantum dot. The comparative study demon-strates that the different structured beams, having unique symmetries and hence properties, have significant effects on the confinement potentials and electron probability densities of the quantum dot. It is shown that the system is most sensitive to the intensity and peak position changes of the zeroth order Bessel beam. Drastic changes in the dressed confinement potentials and electron probability densities under the impact of the above-mentioned beams were demonstrated, which can lead to the usage of the following method in such applications, where the precise manipulation of the charge carrier location is required. This study provides new insights into the role of structured laser fields in quantum dot systems, offering possibilities for their use in advanced nanophotonics and quantum information technologies.

Nanostructures with quantum dots based on GeSi solid solution are promising for the development of optoelectronic devices compatible with modern silicon technology. In this paper, we demonstrate the capabilities of such nanostructures for detecting infrared and terahertz radiation. The working spectral range of nanostructures with GeSi/Si QDs is determined by the energy position of hole levels in the QDs, which is calculated using the quantum box model and confirmed by experimentally measuring the spectra of photoinduced intraband absorption of radiation. Using time-resolved spectroscopy, we found the characteristic times that determine the speed of the detection process associated with the processes of capture and recombination of charge carriers.

Influence of dielectric confinement in exciton–biexciton energetic ordering.

The thermodynamic characteristics of a pair-interacting hole gas localized in a Ge/Si lens-shaped quantum dot are studied. The pair-interaction potential is modeled by the oscillator function, which depends on the distance between the particles. The analytical form of the spectra makes it possible to calculate the partition function in Boltzmann approximation. Based on the partition function mean and free energies, heat capacity and entropy of the interacting gas are calculated. Interaction between particles substantially changes the behavior of the thermodynamic properties in comparison with the non-interacting gas case. In particular, the gas undergoes a first-order phase transition driven by the height of the upper (or lower) section of QD, resulting in a changing symmetry of the lens-shaped QD.

We analyze the spontaneous emission dynamics of a quantum emitter near a topological insulator Bi2Te3 nanosphere, using a combination of electromagnetic calculations and quantum dynamics simulations. For the study of the quantum system dynamics, besides the excited state population dynamics, different non-Markovianity measures are used. We also estimate the quantum speed limit in the system. For large free-space decay rates, the dynamics has strong non-Markovian features, which correlate directly with large values of non-Markovianity measures and possible significant quantum speedup of the dynamics. The dynamical features become gradually Markovian as the free-space decay times become long, while the corresponding non-Markovianity measures tend to zero and the quantum speedup diminishes.

This research is devoted to the electronic characteristics of the biconical quantum dot constructed from GaAs, employing the Finite Element Method. The study initiated with the calculation of wave functions and energies for the ground state and the first four excited states. This enabled the discernment of the influence of the quantum dot's geometry on its electronic configuration. Utilizing the derived wave functions and energies for a single electron, the oscillator strengths for various quantum transitions were determined. The absorption spectrum was observed during transitions from the ground to the next four excited states.

This theoretical study investigates the response of a strongly oblate GaAs ellipsoidal quantum dot to an intense laser field with a Bessel intensity profile at non-resonant extreme violet and simultaneously resonant mid-infrared laser irradiation. Mainly, the linear and nonlinear optical properties of biexcitons in quantum dot are observed. Due to the complexity of the considered particle, all calculations are performed in the framework of the variational method. Biexciton variational function is constructed on the one-particle wave functions, which are correlated with each other by exponents with variational parameters. The biexciton energies for different values of applied intense laser field magnitude on the small geometrical parameter of ellipsoidal quantum dot are calculated. The nonlinear optical properties, including the oscillator strength, third-order nonlinear susceptibility, absorption coefficient, and refractive index change, are evaluated. Numerical results reveal the dependence of the exciton and biexciton energies on the intensity of the laser field and the geometrical parameters of the quantum dot. Additionally, the dependencies of the third-order susceptibility, absorption coefficient, and induced refractive index change on photon energy near the one-photon resonance and two-photon resonance are analyzed. The two-photon absorption coefficient of the biexciton in GaAs ellipsoidal quantum dot is computed, and the spectra of refractive index changes induced by biexciton transitions between ground states are analyzed for different magnitudes of the intense laser field. Biexciton recombination radiative lifetime on the small semiaxis of the ellipsoidal quantum dot for the different values of the laser field influence is estimated. Finally, the visualization of the localization region of biexciton in the ellipsoidal quantum dot is performed.

In the framework of the effective mass approximation the biexciton states have been investigated in the oblate and prolate ellipsoidal quantum dots. To calculate the ground state energy of the biexciton, three-parameters’ variational trial function was utilized. Based on the non-relativistic energy and wave function the lowest-order relativistic correction to the non-relativistic Hamiltonian have been calculated. The relativistic correction energy of the biexciton fine structure have been found to be the order 10−6meV. The relativistic correction approaches zero with increase of the quantum dot sizes. It has been also revealed that the relativistic correction of the biexciton fine structure increases with the increase of size quantization. As a result, the mentioned effect is more pronounced for the case of prolate ellipsoidal quantum dot in the comparison with oblate one.

This paper presents a theoretical investigation of nonlinear properties of coupled quantum dots in the peanut configuration. A complete Hamiltonian is formulated using the adiabatic method and the confinement energy is represented in a cylindrical coordinate system. The effective energy for the slow subsystem is analysed and graphed as a function of a fixed value of axial coordinate for both the asymmetric and symmetric peanut QD cases. The electron motion in the presence of an electric field in the vertical direction is considered, and the eigenfunctions and energy spectrum of electron motion are determined for the same direction utilising the finite element method. The dependence of the first three energy levels on the electric field is shown, and the electron probability density for the ground state and the first excited state is plotted. In addition, calculations for the nonlinear optical properties are presented, particularly optical rectification, second harmonic generation and third harmonic generation. The results demonstrate that these properties can be effectively controlled by varying the external electric field. The findings suggest that coupled peanut QDs hold significant potential for applications in high-performance optoelectronic devices.

The current work used the effective mass approximation conjoined with the finite element method to study the exciton states in a conical GaAs quantum dot. In particular, the dependence of the exciton energy on the geometrical parameters of a conical quantum dot has been studied. Once the one-particle eigenvalue equations have been solved, both for electrons and holes, the available information on energies and wave functions is used as input to calculate exciton energy and the effective band gap of the system. The lifetime of an exciton in a conical quantum dot has been estimated and shown to be in the range of nanoseconds. In addition, exciton-related Raman scattering, interband light absorption and photoluminescence in conical GaAs quantum dots have been calculated. It has been shown that with a decrease in the size of the quantum dot, the absorption peak has a blue shift, which is more pronounced for quantum dots of smaller sizes. Furthermore, the interband optical absorption and photoluminescence spectra have been revealed for different sizes of GaAs quantum dot.