Quantum Dot Sensitized Solar Cells (QDSSCs) represent an advanced class of third-generation photovoltaic devices that utilize the quantum confinement effects of semiconductor nanocrystals for enhanced light harvesting. This study explores CdSe, InP, and CuInS₂-based QDSSCs synthesized via SILAR and hot-injection techniques, emphasizing tunable bandgaps, multiple exciton generation (MEG), and surface passivation for improved performance. UV–V is spectra revealed bandgaps between 1.5–2.5 eV, dependent on particle size. Under AM 1.5G illumination, CdSe-based devices achieved 5.0% power conversion efficiency (PCE), outperforming InP (3.3%) and CuInS₂ (2.7%) devices. Electrochemical impedance spectroscopy confirmed that CdSe exhibited the lowest charge-transfer resistance and highest electron lifetime. A case study using Delhi’s July 2025 solar irradiance data demonstrated 21.6% efficiency for a 3 kW system and an average output of 17.21 kWh/day for a 10 kW installation. These findings indicate that while CdSe QDs deliver higher efficiency, eco-friendly alternatives such as InP and CuInS₂ offer sustainable solutions. Integrating solid-state electrolytes, core–shell architectures, and scalable deposition methods can drive QDSSCs toward commercialization in flexible, wearable, and building-integrated photovoltaic.
This study investigates the optimization of online compressor washing frequency for enhanced performance and profitability of industrial gas turbines. Two representative engines: an aero-derivative LM2500 and a heavy-duty V94.3A (also designated SGT5-4000F) were simulated in GasTurb software under varying washing intervals of one day and ten days. Experimental data were applied to model reductions in compressor isentropic efficiency and mass-flow capacity due to fouling. The results indicate that extending the washing interval from daily to every ten days for one year causes significant performance deterioration. For the LM2500, power output decreased from 7 % to 16 %, thermal efficiency from 2.6 % to 6 %, and heat rate rose from 2.7 % to 6.6 %. Corresponding changes for the V94.3A were smaller, confirming that the aero-derivative turbine is more sensitive to fouling than the heavy-duty unit. Economic evaluation showed that while more frequent washing increased wash fluid consumption and operational costs, it provides substantial financial benefits. Daily washing produced additional annual net profits of approximately £11.69 million for the V94.3A and £4.6 million for the LM2500 compared with ten-day intervals. Overall, the findings demonstrate that optimizing compressor washing frequency is essential to sustain turbine performance, improve fuel efficiency, and maximize profitability. Frequent online washing mitigates the adverse effects of fouling and ensures cost-effective, reliable, and energy-efficient gas-turbine operation.
An investigation has been conducted on structural and electronic characteristics of cubic half heusler compound AcOF. The FP-LAPW approach is used in density functional theory (DFT) to conduct the investigation. GGA scheme was applied to verify the structural stability. The lattice parameter, unit cell volume, bulk modulus, and pressure derivative of bulk modulus are among the ground-state characteristics that are calculated. The calculated GGA lattice parameters correlate well with the available data. Band structure, density of state and charge density have been plotted. Electronic band structure confirms AcOF as an insulator having large band gap.
Richard L. Greene, Pampa R. Mandal, Nicholas R. Poniatowski
et al.
An understanding of the high-temperature copper oxide (cuprate) superconductors has eluded the physics community for over thirty years, and represents one of the greatest unsolved problems in condensed matter physics. Particularly enigmatic is the normal state from which superconductivity emerges, so much so that this phase has been dubbed a "strange metal." In this article, we will review recent research into this strange metallic state as realized in the electron-doped cuprates with a focus on their transport properties. The electron-doped compounds differ in several ways from their more thoroughly studied hole-doped counterparts, and understanding these asymmetries of the phase diagram may prove crucial to developing a final theory of the cuprates. Most of the experimental results discussed in this review have yet to be explained and remain an outstanding challenge for theory.
Karyn Le Hur, Philippe Doucet-Beaupre, Walter Hofstetter
We investigate the entanglement between a spin and its environment in impurity systems which exhibit a second-order quantum phase transition. As an application, we employ the spin-boson model, describing a two-level system (spin) coupled to a subohmic bosonic bath with power-law spectral density, ${\cal J}(ω)\propto ω^s$ and $0<s<1$. Combining Wilson's Numerical Renormalization Group method and hyperscaling relations, we demonstrate that the entanglement between the spin and its environment is always enhanced at the quantum phase transition resulting in a visible cusp (maximum) in the entropy of entanglement. We formulate a correspondence between criticality and impurity entanglement entropy, and the relevance of these ideas to Nano-systems is outlined.
Polymer translocation in three dimensions out of planar confinements is studied in this paper. Three membranes are located at $z=-h$, $z=0$ and $z=h_1$. These membranes are impenetrable, except for the middle one at $z=0$, which has a narrow pore. A polymer with length $N$ is initially sandwiched between the membranes placed at $z=-h$ and $z=0$ and translocates through this pore. We consider strong confinement (small $h$), where the polymer is essentially reduced to a two-dimensional polymer, with a radius of gyration scaling as $R^{\tinytext{(2D)}}_g \sim N^{ν_{\tinytext{2D}}}$; here, $ν_{\tinytext{2D}}=0.75$ is the Flory exponent in two dimensions. The polymer performs Rouse dynamics. Based on theoretical analysis and high-precision simulation data, we show that in the unbiased case $h=h_1$, the dwell-time $τ_d$ scales as $N^{2+ν_{\tinytext{2D}}}$, in perfect agreement with our previously published theoretical framework. For $h_1=\infty$, the situation is equivalent to field-driven translocation in two dimensions. We show that in this case $τ_d$ scales as $N^{2ν_{\tinytext{2D}}}$, in agreement with several existing numerical results in the literature. This result violates the earlier reported lower bound $N^{1+ν}$ for $τ_d$ for field-driven translocation. We argue, based on energy conservation, that the actual lower bound for $τ_d$ is $N^{2ν}$ and not $N^{1+ν}$. Polymer translocation in such theoretically motivated geometries thus resolves some of the most fundamental issues that are the subjects of much heated debate in recent times.
Past theoretical studies have considered excitations of a given flavor of composite fermions across composite-fermion quasi-Landau levels. We show that in general there exists a ladder of flavor changing excitations in which composite fermions shed none, some, or all of their vortices. The lowest energy excitations are obtained when the composite fermions do not change their flavor, whereas in the highest energy excitations they are stripped of all of their vortices, emerging as electrons in the final state. The results are relevant to the intriguing experimental discovery of Hirjibehedin {\em et al.} (cond-mat/0306152) of coexisting excitation modes of composite fermions of different flavor in the filling factor range $1/3>ν\geq 1/5$.
We explore the conditions under which colloids can be stabilized by the addition of smaller particles. The largest repulsive barriers between colloids occur when the added particles repel each other with soft interactions, leading to an accumulation near the colloid surfaces. At lower densities these layers of mobile particles (nanoparticle halos) result in stabilization, but when too many are added, the interactions become attractive again. We systematically study these effects --accumulation repulsion, re-entrant attraction, and bridging -- by accurate integral equation techniques.
A particle subject to successive, random displacements is said to execute a random walk (in position or some other coordinate). The mathematical properties of random walks have been very thoroughly investigated, and the model is used in many areas of science and engineering as well as other fields such as finance and the life sciences. This letter describes a phenomenon occurring in a natural extension of this model: we consider the motion of a large number of particles subject to successive random displacements which are correlated in space, but not in time. If these random displacements are smaller than their correlation length, the trajectories coalesce onto a decreasing number of trails. This surprising effect is explained and quantitative results are obtained. Various possible realisations are discussed, ranging from coalescence of the tracks of water droplets blown off a windshield to migration patterns of animals.
In a recent Letter, Jiang, Sun, Xie and Wang [Phys. Rev. Lett. 93, 076802 (2004), cond-mat/0408261] study transport through an interacting quantum dot embedded in one arm of an Aharonov-Bohm interferometer. Based on a theoretical analysis of the Aharonov-Bohm oscillation amplitude, Jiang {\it et al.} claim, contrary to earlier work by two of us, that at finite temperature the intradot interaction will {\em not} lead to any dephasing. Likewise, they claim that the theoretically predicted and experimentally verified asymmetry of the Aharonov-Bohm oscillation amplitude is {\em not} associated with dephasing. In this Comment, we point out severe inconsistencies in the analysis of the Letter by Jian {\it et al.}, and show that their conclusions are ill-founded.
We investigate the occurrence of a two-step spin-flop transition and spin reorientation when a longitudinal magnetic field is applied to lightly hole-doped La(2)CuO(4). We find that for large and strongly frustrating impurities, such as Sr in La(2-x)Sr(x)CuO(4), the huge enhancement of the longitudinal susceptibility suppresses the intermediate flop and the reorientation of spins is smooth and continuous. Contrary, for small and weakly frustrating impurities, such as O in La(2)CuO(4+y), a discontinuous spin reorientation (two-step spin-flop transition) takes place. Furthermore, we show that for La(2-x)Sr(x)CuO(4) the field dependence of the magnon gaps differs qualitatively from the La(2)CuO(4) case, a prediction to be verified with Raman spectroscopy or neutron scattering.
It is suggested a topological hierarchical classification of the infinite many Localized phases figuring in the phase diagram of the Harper equation for anisotropy parameter $ε$ versus Energy $E$ with irrational magnetic flux $ω$. It is also proposed a rule that explain the fractal structure of the phase diagram. Among many other applications, this system is equivalent to the Semi-classical problem of Bloch electrons in a uniform magnetic field, the Azbel-Hofstadter model, where the discrete magnetic translations operators constitute the quantum algebra $U_q(sl_2)$ with $q^2=e^{i2πω}$. The magnetic flux is taken to be the golden mean $ω^*=(\sqrt{5}-1)/2$ and is obtained by successive rational approximants $ω_m=F_{m-1}/F_m$ with $F_m$ given by the Fibonacci sequence $F_m$.[OUTP-00-08S, \texttt{cond-mat/0011396}]
We review the main result of cond-mat/0503564. The Hamiltonian of the XXZ spin chain and the transfer matrix of the six-vertex model has the $sl_2$ loop algebra symmetry if the $q$ parameter is given by a root of unity, $q_0^{2N}=1$, for an integer $N$. We discuss the dimensions of the degenerate eigenspace generated by a regular Bethe state in some sectors, rigorously as follows: We show that every regular Bethe ansatz eigenvector in the sectors is a highest weight vector and derive the highest weight ${\bar d}_k^{\pm}$, which leads to evaluation parameters $a_j$. If the evaluation parameters are distinct, we obtain the dimensions of the highest weight representation generated by the regular Bethe state.
We provide an article-extract which points out that a microwave-induced modification in the resistance occurs at relatively "high" magnetic fields where the radiation is incapable of producing inter-Landau level excitations and, therefore, that the microwave radiation must be producing intra Landau level excitations as well.
Motivated by a large number of recent magnetotransport studies we have revisited the problem of the microscopic calculation of the quasiparticle effective mass in a paramagnetic two-dimensional (2D) electron liquid (EL). Our systematic study is based on a generalized $GW$ approximation which makes use of the many-body local fields and takes advantage of the results of the most recent QMC calculations of the static charge- and spin-response of the 2D EL. We report extensive calculations for the many-body effective mass enhancement over a broad range of electron densities. In this respect we critically examine the relative merits of the on-shell approximation, commonly used in weak-coupling situations, {\it versus} the actual self-consistent solution of the Dyson equation. We show that already for $r_s \simeq 3$ and higher, a solution of the Dyson equation proves here necessary in order to obtain a well behaved effective mass. Finally we also show that our theoretical results for a quasi-2D EL, free of any adjustable fitting parameters, are in good qualitative agreement with some recent measurements in a GaAs/AlGaAs heterostructure.
Recently, the ``$(p+h)-$wave'' form of pairing symmetry has been proposed for the superconductivity in $PrOs_{4}Sb_{12}$ compound [Parker D, Maki K and Haas S, \textbf{cond-mat/0407254}]. In the present paper, a stationary Josephson junction as a weak-link between $PrOs_{4}Sb_{12}$ triplet superconductors is theoretically investigated. The quasiclassical Eilenberger equations are analytically solved. The spin and charge current-phase diagrams are plotted and the effect of misorientation between crystals on the spin current, and spontaneous and Josephson currents is studied. It is found that such experimental investigations of the current-phase diagrams can be used to test the pairing symmetry in the above-mentioned superconductors. It is shown that this apparatus can be applied as a polarizer for the spin current.
From magnetisation measurements we provide evidence that the ferromagnetic superconductor RuSr$_{2}$GdCu$_{2}$O$_{8}$ with \QTR{it}{T}$_{c}$=45 K and \QTR{it}{T}$_{M}$=137 K exhibits a sizeable diamagnetic signal at low temperature (\QTR{it}{T}<\QTR{it}{T}$^{\QTR{it}{ms}}$=30 K) and low magnetic field (\QTR{it}{H}$^{ext}$<30 Oe), corresponding to a bulk Meissner-phase. At intermediate temperatures, \QTR{it}{T}$^{\QTR{it}{ms}}$<\QTR{it}{T}<\QTR{it}{T}$_{c}$, a spontaneous vortex phase forms which is characterized by unique thermal hysteresis effects. We argue that a recent negative report [C.W. Chu et al., cond-mat/9910056] regarding the Meissner-effect in Ru-1212 can be explained by impurity scattering or grain size effects.