Small Energy Loss Research Articles

A Rolling Soft Robot Driven by Local Snap-Through Buckling.

Previous rolling soft robots have difficulty in balancing the locomotion speed with energy efficiency and have limited terrain adaptability. This work proposes a rolling soft robot driven by local snap-through buckling, which employs the fast response and configuration maintenance of the bistable structure to enhance the locomotion performance of the soft robot. A theory based on bifurcation and the energy principle is established to analyze the rolling mechanism. The influences of loading position and geometric parameters on the rolling performance are investigated and verified experimentally. The soft robot shows good locomotion speed (0.95 body length per second, BL/s) and small energy loss due to the almost unchanged configuration during the rolling process. The soft robot adapts to complex terrains, including a step with the height of 15 mm, a slope with the angle of 18.36°, and a broken bridge with the gap length of 90 mm (0.443 BL). The proposed rolling soft robot not only has good application prospects in land exploration missions and medical applications but also provides inspiration for the development of rolling soft robots.

Reorientation Transition Between Square and Hexagonal Skyrmion Lattices near the Saturation into the Homogeneous State in Quasi-Two-Dimensional Chiral Magnets.

I revisit the well-known phase transition between the hexagonal skyrmion lattice and the homogeneous state within the phenomenological Dzyaloshinskii theory for chiral magnets, which includes only the exchange, Dzyaloshinskii-Moriya, and Zeeman energy contributions. I show that, in a narrow field range near the saturation field, the hexagonal skyrmion order gradually transforms into a square arrangement of skyrmions. Then, by the second-order phase transition during which the lattice period diverges, the square skyrmion lattice releases a set of repulsive isolated skyrmions. On decreasing the magnetic field, isolated skyrmions re-condense into the square lattice at the same critical field as soon as their eigen-energy becomes negative with respect to the field-aligned state. The underlying reason for the reorientation transition between two skyrmion orders can be deduced from the energy density distribution within isolated skyrmions surrounded by the homogeneous state. When the negative energy within the ring-shaped area at the skyrmion outskirt outweighs the positive energy amount around the skyrmion axis, skyrmions tend to form the square lattice, in which the overlap of skyrmion profiles results in smaller energy losses as compared with the hexagonal crystal. With the further decreasing field, the hexagonal lattice achieves smaller energy density in comparison with the square one due to the denser packing of individual skyrmions.

A theoretical investigation of ABO3 (A=Na and B = Ti, In) perovskites for solar cell and optoelectronic applications

Oxide-perovskites are becoming the leading aspirants to meet the need for energy conversion and optoelectronics devices. Therefore, Na-based novel oxide-perovskite ABO3 (A = Na and B=Ti, In) compounds have been investigated for their physical properties within the density functional theory (DFT) based calculations. These calculations show that both compounds comprise a cubic structure with the space group of Pm3m. The general structural stability of these compounds has been evaluated using the formation enthalpy computations. Mechanical stability is confirmed by the results of three elastic coefficients C11, C12, and C44. NaInO3 shows a ductile character, while NaTiO3 shows a brittle character. The total density of states (TDOS) and partial density of states (PDOS) confirm the amount of electron concentration in specific bands. The band gap values of 2.12–2.71 eV are reported in the electronic band structures, which makes them more significant for optoelectronic applications. Both NaTiO3 and NaInO3 have good refractive indices, low optical reflectivity, small electron energy loss, and a high absorption coefficient in the visible (VIS) and ultraviolet (UV) spectrums. The results of the combined structural, electronic, optical, and mechanical studies demonstrate that both materials are potential candidates for practical applications, particularly in optoelectronic and solar cell technologies. Consequently, these findings can motivate the upcoming theoretical and experimental investigations.

Inner Side Chain Modification of Small Molecule Acceptors Enables Lower Energy Loss and High Efficiency of Organic Solar Cells Processed with Non-halogenated Solvents.

Organic solar cells (OSCs) processed with non-halogenated solvents usually suffer from excessive self-aggregation of small molecule acceptors (SMAs), severe phase separation and higher energy loss (Eloss), leading to reduced open-circuit voltage (Voc) and power conversion efficiency (PCE). Regulating the intermolecular interaction to disperse the aggregation and further improve the molecular packing order of SMAs would be an effective strategy to solve this problem. Here, we designed and synthesized two SMAs L8-PhF and L8-PhMe by introducing different substituents (fluorine for L8-PhF and methyl for L8-PhMe) on the phenyl end group of the inner side chains of L8-Ph, and investigated the effect of the substituents on the intermolecular interaction of SMAs, Eloss and performance of OSCs processed with non-halogenated solvents. Through single crystal analysis and theoretical calculations, it is found that compared with L8-PhF, which possesses strong and abundant intermolecular interactions but downgraded molecular packing order, L8-PhMe with the methyl substituent possesses more effective non-covalent interactions, which improves the tightness and order of molecular packing. When blending the SMAs with polymer donor PM6, the differences in intermolecular interactions of the SMAs influenced the film formation process and phase separation of the blend films. The L8-PhMe based blend film exhibits shorten film formation and more homogeneous phase separation than those of the L8-PhF and L8-Ph based ones. Especially, the OSCs based on L8-PhMe show reduced non-radiative energy loss and enhanced Voc than the devices based on the other two SMAs. Consequently, the L8-PhMe based device processed with o-xylene (o-XY) and using 2PACz as the hole transport layer (HTL) shows an outstanding PCE of 19.27 %. This study highlights that the Eloss of OSCs processed with non-halogenated solvents could be decreased through regulating the intermolecular interactions of SMAs by inner side chain modification, and also emphasize the importance of effectivity rather than intensity of non-covalent interactions introduced in SMAs on the molecular packing, morphology and PCE of OSCs.

Mechanical properties of hydrated electrospun polycaprolactone (PCL) nanofibers

Polycaprolactone (PCL) nanofibers are a promising material for biomedical applications due to their biocompatibility, slow degradation rate, and thermal stability. We electrospun PCL fibers onto a striated substrate with 12 μm wide ridges and grooves and determined their mechanical properties in an aqueous solution with a combined atomic force/inverted optical microscopy technique. Fiber diameters, D, ranged from 27 to 280 nm. The hydrated PCL fibers had an extensibility (breaking strain), εmax, of 137%. The Young's modulus, E, and tensile strength, σT, showed a strong dependence on fiber diameter, D; decreasing steeply with increasing diameter, following empirical equations E(D)=(4.3∙103∙e−D51nm+1.1∙102) MPa and σT(D)=(2.6∙103∙e−D55nm+0.6∙102) MPa. Incremental stress-strain measurements were employed to investigate the viscoelastic behavior of these fibers. The fibers exhibited stress relaxation with a fast and slow relaxation time of 3.7 ± 1.2 s and 23 ± 8 s and these experiments also allowed the determination of the elastic and viscous moduli. Cyclic stress-strain curves were used to determine that the elastic limit of the fibers, εelastic, is between 19% and 36%. These curves were also used to determine that these fibers showed small energy losses (<20%) at small strains (ε < 10%), and over 50% energy loss at large strains (ε > 50%), asymptotically approaching 61%, as Eloss=61%·(1−e−0.04*ε). Our work is the first mechanical characterization of hydrated electrospun PCL nanofibers; all previous experiments were performed on dry PCL fibers, to which we will compare our data.

APPLİCATİON OF THE WORKİNG FLUİD İN THE HYDRAULİC TRANSMİSSİON

Issues related to the determination of the steady-state temperature of the hydraulic systems of volume hydraulic devices for the stability of the output lane are of great importance. Therefore, it is necessary to know the time for the hydraulic system of the volume hydraulic actuator to reach a stable temperature regime. The transition mode is a complex function of a large number of variables, and at the same time it is necessary that it should be as short as possible, which will save both power consumption and idle operating time of the installation. First of all, the parameters that influence the dynamics of the flow processes of volumetric hydraulic machines are their pressure, hydraulic system, initial temperature of hydraulic equipment, ambient temperature, availability of cooling devices and, as already mentioned above, hydropower coefficients. In this regard, the topic of this paper is relevant, and even a partial, qualitative study of the dynamics of temperature fields can be useful for understanding the physical state of what is happening in hydraulic machines. The hydraulic machine has a high special power for a single mass (7.36-8.83 kW per 1 kg of mass), and even relatively small relative energy losses lead to significant prices for a special heat flux g &gt; 600 kVt/m2. Due to local overheating of individual sections of the surface of the hydraulic machine, a certain part of the heat in unsteady mode is spent on changing the temperature of the housing and its individual components and parts. This article examines the dynamics of the temperature field during operation and extinguishing using the example of the most used gear pump for a positive-position hydraulic machine. Keywords: hydraulic systems, hydraulic equipment, temperature, dynamic mode, working fluid.

Two-stage crash process in resistive drift ballooning mode driven ELM crash

We report a two-stage crash process in edge localized mode (ELM) driven by resistive drift-ballooning modes (RDBMs) numerically simulated in a full annular torus domain with a scale-separated four-field reduced MHD (RMHD) model using the BOUT++ framework. In the early nonlinear phase, the small first crash is triggered by linearly unstable RDBMs, and m/n=2/1 magnetic islands are nonlinearly excited by nonlinear coupling of RDBMs as well as their higher harmonics. Here, m is the poloidal mode number, n is the toroidal mode number, the q = 2 rational surface exists near the pressure gradient peak, and q is the safety factor. Simultaneously, middle-n RDBM turbulence develops but is poloidally localized around X-points of the magnetic islands, leading to the small energy loss. The second large crash occurs in the late nonlinear phase. Higher harmonics of m/n=2/1 magnetic islands well develop around the q = 2 surface via nonlinear coupling and make the magnetic field stochastic by magnetic island overlapping. Turbulence heat transport develops at X-points of higher harmonics of m/n=2/1 magnetic islands, resulting in the turbulence spreading in the poloidal direction. The large second crash is triggered when the turbulence covers the whole poloidal region so that the magnetic island generation and magnetic field stochastization before the large crash can be interpreted as ELM precursors. It is concluded that the ELM trigger is attributed to the turbulent spreading in the poloidal direction in synchronization with the magnetic field stochastization and the crash is driven by E × B convection rather than the conventional Rechester–Rosenbluth anomalous electron heat transport.

Efficient triisopropylsilylethynyl-substituted benzo[1,2-b:4,5-b′]dithiophene-based random terpolymers enable non-fullerene organic solar cells with enhanced efficiency

Recent work has highlighted the pivotal role of ternary random polymers in the development of efficient high-performance polymer donors for organic solar cells (OSCs) and most of these D-A copolymer donors are so far constituted of an equal proportion of D and A-units. In this contribution, we report series of PM6-based ternary random terpolymers with unequal D- and A-units, namely, PM-TIPS10, PM-TIPS20 and PM-TIPS20, respectively by adding the 10%, 20% and 30% of simple and low-cost triisopropylsilylethynyl-substituted benzo[1,2-b:4,5-b′]dithiophene (BDT-TIPS) unit as second donor (D1) unit in polymer backbone based on D1-A-D2-A molecular design. Ascribed from the structural similarity of the two building blocks in the terpolymer backbone, these polymers showed orderly molecular packing, broadened light absorption, and the face-on orientation of the active layer to facilitate charge transport. Additionally, the new polymers displayed much deeper highest occupied molecular orbital (HOMO) energy levels than host PM6 polymer, which helped in enhancing the open circuit voltage (Voc) in the PM-TIPS-based OSCs. As a result, when combined with BTP-eC9 acceptor unit, PM-TIPS10 and PM-TIPS20 displayed best efficiency of 16.7 and 16.5% with a small energy loss of 0.484 and 0.473 eV, producing overall superior device parameters compared to PM6-based devices tested parallelly (PCE of 15.7%). This study reveals the correlation between introduction of the BDT-TIPS unit on polymer properties and photovoltaic performance and thus contributes to the design of high-PCE polymer donors by adapting a ternary random copolymerization strategy.

Influence of PCM configuration and optimization of PCM proportion on the thermal management of a prismatic battery with a combined PCM and air cooling structure

Different configurations and proportion of phase change material (PCM) have a vital impact on the thermal performance of the battery thermal management system (BTMS). In this work, the thermal performance of the battery pack is investigated by a combined PCM and air cooling technique. Firstly, four cases of PCM configuration are proposed to investigate the heat dissipation performance. Then PCM proportion is optimized to obtain better temperature uniformity, smaller energy loss and smaller amount of PCM based on Case 4. Finally, subjected to the installation space constraint of battery box (smaller volume), Case 5 is designed to diminish the volume of battery box and the corresponding thermal performance is discussed. The results show that thermal performance with PCM is superior than that without PCM; Case 4 not only enhances the thermal performance but also reduces the amount of PCM; The optimized PCM proportion is only 64 %; Compared with all PCM, the optimized ΔT, ΔP and PCM volume respectively reduce 11.91 % (0.83 K), 11.61 % (4.18 Pa) and 43.06 % (215,544 mm3); Case 5 not only shows more better thermal performance than Case 4 but also reduces 102,200 mm3 (3.48 %) volume of the battery box. The proposed strategy is effective for improving thermal performance of BTMS and saving the amount of PCM.

Effect of work function on dust charging and dynamics near lunar surface

Charged dust on the lunar surface poses a threat to space missions. Research into charged dust is essential for the safety of future space missions. When calculating the charging currents related to photoelectrons, a single constant work function is assumed in the conventional lunar dust charging theory. However, the components of lunar regolith exhibit considerable diversity, including plagioclase, pyroxene, and ilmenite. Because the ability of the lunar surface or lunar dust to emit photoelectrons strongly depends on its work function, it is necessary to analyze the effect of the work function on dust charging and dynamics near the lunar surface. In this work, we use a novel method that can predict the photoelectric yield of materials with different work functions to recalculate the surface charging currents of four types of dust particles and derive their subsequent charging and dynamic results at different solar zenith angles (SZAs). As SZA varies from 0° to 90°, the work function value of dust decreases into 6 eV (Apollo lunar soil), 5.58 eV (plagioclase), 5.14 eV (pyroxene), and 4.29 eV (ilmenite), correspondingly. With each decrement in work function, the equilibrium charging current of dust particles increases about 0.25 times, the equilibrium charge number increases about 120–170 elemental charges, and the equilibrium height increases about 0.3–2 m. It is found that dust particles cannot levitate stably at a critical SZA, and the critical SZAs for the four types of dust particles are 28°, 76°, 85.8°, and 89.6°, respectively (arranged in decreasing order of work functions). These results indicate that the equilibrium heights, equilibrium currents, and critical SZAs all have an inverse relationship with the work function of dust particles as the SZA varies from 0° to 90°. Furthermore, a higher photoelectron density in areas with lower work functions leads energy losses to decrease, thus causing dust particles to take longer time to reach equilibrium. This means that the equilibrium time follows the pattern similar to that of the work function.

Reconfigurable and Phase‐Engineered Acoustic Metasurfaces for Broadband Wavefront Manipulation

AbstractA novel type of phase‐engineered acoustic metasurfaces with reconfigurable properties is reported, enabling the flexible broadband manipulation of reflected wavefronts. The participants of the metasurface are elements conceived to possess even‐distributed reflected phases covering 2π span with linearity and small acoustic energy loss. The reconfigurable property of the metasurface is implemented by rearranging the fixed meta‐elements based on the phase profile, which is related to the characteristic of a specific wavefront shape. The metasurface's capability is successfully demonstrated to achieve acoustic focusing and bending within the frequency range of 2300–2800 Hz, showcasing its feasibility and adaptability. To enhance its practical applications, porous materials are incorporated, leveraging the robustness of phase differences among the meta‐elements to achieve high acoustic energy cancellation. Effective sound attenuation occurs within the frequency range of 1300–3100 Hz, even under wide‐angle incidences ranging from −80° to 80°. The work paves the way for further research on reconfigurable acoustic metasurfaces in broad frequency regions and exerts favorable implications for generally applicable structures applied in multi‐fields including biomedical acoustics, noise control, and so on.

Energy losses in photovoltaic generators due to wind patterns

Previously, in small scale demonstrations, researchers have increased photovoltaic efficiency through cooling by enhancing heat transfer from panels to the air through wind speed. Here I show in the real-world operation of a larger scale photovoltaic generator that increases in wind speed can lead to small but notable energy losses, reflected in the mismatch losses directly derived from the operating voltage of each module. Temperature distribution was measured simultaneously with the operating voltages, alongside the local wind speed and direction. Temperature differences arose from the variable heat transfer throughout the panel, depending on the wind incidence. This affected the operating temperature of each module, consequently affecting their operating voltage and the overall mismatch losses with losses increasing by up to 0.28%. My results suggest that wind patterns cannot be neglected, considering long-term energy estimations and the lifespan of a photovoltaic power plant.

Pd2 MnGa Metamagnetic Shape Memory Alloy with Small Energy Loss.

Metamagnetic shape memory alloys (MMSMAs) are attractive functional materials owing to their unique properties such as magnetostrain, magnetoresistance, and the magnetocaloric effect caused by magnetic-field-induced transitions. However, the energy loss during the martensitic transformation, that is, the dissipation energy, Edis , is sometimes large for these alloys, which limits their applications. In this paper, a new Pd2 MnGa Heusler-type MMSMA with an extremely small Edis and hysteresis is reported. The microstructures, crystal structures, magnetic properties, martensitic transformations, and magnetic-field-induced strain of aged Pd2 MnGa alloys are investigated. A martensitic transformation from L21 to 10M structures is seen at 127.4K with a small thermal hysteresis of 1.3K. The reverse martensitic transformation is induced by applying a magnetic field with a small Edis (=0.3Jmol-1 only) and a small magnetic-field hysteresis (=7kOe) at 120K. The low values of Edis and the hysteresis may be attributed to good lattice compatibility in the martensitic transformation. A large magnetic-field-induced strain of 0.26% is recorded, indicating the proposed MMSMA's potential as an actuator. The Pd2 MnGa alloy with low values of Edis and hysteresis may enable new possibilities for high-efficiencyMMSMAs.

End-capped modeling of dithienopicenocarbazole based derivatives for high-performance photovoltaic cells with optoelectronic response over 900 nm

Dithienopicenocarbazole (DTPC), as the inner core in the A-D-A configuration, has been recognized for its exceptionally small energy loss, narrow energy gap, and excellent power conversion efficiency. In this work, a series of six novel dithienopicenocarbazole-based molecules with wide absorption and remarkable opto-electrical properties, were designed as the new electron-donating materials for organic photovoltaic devices. (DI1-DI6) were derived by substituting end-capped moieties attached to the middle core (DTPC) with highly conjugated and electro withdrawing groups and insertion of π spacer between the donor part and the newly attached acceptor part. The findings demonstrated that the modified molecules had smaller excitation energies (Ex), a decreased energy gap (Eg), and have higher absorption (λmax) values in comparison to the DIR (reference structure). The greatest λmax (980 nm), smallest Ex (1.21 eV), and shortest Eg (1.63 eV) were all displayed by the DI4 molecule. In addition, due to its lowest RE value for the electron, DI4 might have best electron carrier ability among all. Furthermore, upon coupling each examined molecule with a PC61BM acceptor, the value of open circuit voltage (VOC) was computed. DI4 displayed the most suitable outcomes for the VOC (1.45 V), FF (0.91178) and normalized VOC (56.14). Therefore, all the altered structures, with special reference DI4, are strongly recommended to synthesize organic photovoltaic cells with exceptional optoelectronic and photovoltaic applications.

Environmental fluid mechanics of minimum energy loss weirs: hydrodynamics and self-aeration at Chinchilla MEL weir during the November–December 2021 flood event

During the recent decades, a number of overflow embankment protection systems were implemented. One design is the Minimum Energy Loss (MEL) weir, developed to pass large flood events with minimum energy loss and low erosion. Several MEL weirs have successfully operated for decades in Australian catchments affected by heavy tropical and sub-tropical rainfalls with very flat gradients. Their historical performances are discussed and confirmed the design capability to pass large floods with small afflux and very small energy loss and little environmental impact including no significant erosion at the abutments. During a major flood, visual and quantitative observations were undertaken at the Chinchilla MEL weir. On the smooth converging chute, the observations showed that the inception of self‐aeration was a three‐dimensional process with a gradual change in free‐surface roughness, from a smooth glassy free-surface to a very-rough choppy surface. An optical technique (OF) was implemented to derive the contour maps of surface velocities based upon video movies taken from a sturdy tripod. The self-aerated flow velocity data were close to the backwater equation in the self‐aerated region, while highlighting regions of high- and low-velocities across the chute. The OF data showed large streamwise surface velocity fluctuations in the aerated flow region, consistent with the broad literature on self-aerated flow measurements. The ratio of transverse to streamwise surface turbulence intensity indicated a strong anisotropy of the free-surface turbulence.

Effect of negative triangularity on peeling-ballooning instability

Experiments have achieved high confinement discharges in tokamaks with a negative triangularity (NT) plasma shape accompanied by a lower pedestal and smaller and more frequent edge localized modes (ELMs) compared with positive triangularity (PT). Some existing theories emphasize the linear instability variations result from the change of pedestal. However, NT can directly bring significant changes on magnetic field structures which may also influence the instability of ELMs. Based on a series of equilibria constructed with different triangularities and pressure profiles, the influence of NT on peeling-ballooning mode (P–B mode) is investigated. It is found that NT can increase the growth rates of low to intermediate n (toroidal mode number) modes in the linear stage and lead to a larger pedestal collapse in the nonlinear stage if its pressure profile is the same with the PT shape. Further analyses demonstrate that NT enlarges the unfavorable curvature area, which provides stronger driving source and larger unstable region for the instability. Meanwhile, the diamagnetic effect and local magnetic shear helps to stabilize high n modes in the linear phase, and the E × B shearing rate at the top of the pedestal contributes to suppress the transport of turbulence into the plasma core in the nonlinear phase for the NT shape. What’s more, further simulations with different pedestal heights demonstrate that there exists a threshold value of pressure ratio, below which the ELM energy loss in NT shapes can be smaller than that in PT shapes, suggesting that the smaller energy loss with NT in experiment mainly results from the lower pedestal heigh. The results reveal behaviors of P–B modes and provide possible mechanisms for the phenomenon of lower pedestal height with negative triangularities in experiments.

Analysis and Comparison of Two Stage and Single Stage Operational Amplifiers Using 0.18µm Technology

Operational amplifier exists in many numbers of configurations. The there are many types of the Operational amplifiers. These are: two stage, single stage, three stage and multistage amplifiers. Identifying the better op amp is important to get better application. The better op amp will be selected by considering the performance parameters (DC Gain, Slew Rate, Power Dissipation, etc.) of op amp. In project work a two stage cmos and single stage CMOS operational has been compared and contrasted based on values of their performance parameters by using 0.18µm CMOS technology and the same power supply (5V). Based on these values, By comparing the performance parameters single stage CMOS op amp is more stable and operate longer duration of time than two stage cmos op amp with small energy loss; while two stage op amp produces the output which is twice larger than single stage op amp, and also the noise in the output of two stage op amp is less than single stage op amp. So to get more output it is better to use two stage op amps. By results and reasons suitable choices for high gain and high performance applications are two stage topologies.

In Situ Study the Dynamics of Blade‐Coated All‐Polymer Bulk Heterojunction Formation and Impact on Photovoltaic Performance of Solar Cells

All‐polymer solar cells (all‐PSCs) have achieved impressive progress by employing acceptors polymerized from well performing small‐molecule non‐fullerene acceptors. Herein, the device performance and morphology evolution in blade‐coated all‐PSCs based on PBDBT:PF5–Y5 blends prepared from two different solvents, chlorobenzene (CB), and ortho‐xylene (o‐XY) are studied. The absorption spectra in CB solution indicate more ordered conformation for PF5–Y5. The drying process of PBDBT:PF5–Y5 blends is monitored by in situ multifunctional spectroscopy and the final film morphology is characterized with ex situ techniques. Finer‐mixed donor/acceptor nanostructures are obtained in CB‐cast film than that in o‐XY‐cast ones, corresponding to more efficient charge generation in the solar cells. More importantly, the conformation of polymers in solution determines the overall film morphology and the device performance. The relatively more ordered structure in CB‐cast films is beneficial for charge transport and reduced non‐radiative energy loss. Therefore, to achieve high‐performance all‐PSCs with small energy loss, it is crucial to gain favorable aggregation in the initial stage in solution.

Reconstruction of the muon production longitudinal profiles in extensive air showers

Muons produced in extensive air showers have large decay lengths and small radiative energy losses, enabling a large fraction of them to reach surface and underground detector arrays while keeping relevant information about the hadronic interactions that occurred high in the atmosphere. We can relate a muon’s arrival time and position at the detector to its production depth in the atmosphere. The total delay of muons with respect to the shower plane is primarily due to their geometric path and energy, we call these contributions the geometric and kinematic delays, respectively. We are working on the improvement of the current kinematic delay parameterizations using Deep Neural Networks for muons arriving at surface and underground detector arrays. We aim to reconstruct the longitudinal profile of muons for future arrays of buried scintillator detectors at energies from around the second knee to the ankle of the cosmic ray spectrum, where there is an overlap with the nominal energies at the LHC. Given the low acceptance of scintillator detectors to inclined air showers and the richness of the forward physics near the shower core, we aim at applying a radial cut of 200 m instead of the usual 1000 m used in previous works.

Panchromatic small-molecule organic solar cells based on a pyrrolopyrrole aza-BODIPY with a small energy loss

A small photon energy loss (Eloss) is one of the requisites for achieving near-infrared (NIR) small-molecule organic solar cells (SM-OSCs). Herein, we present two novel pyrrolopyrrole aza-BODIPY (PPAB)-based panchromatic chromophores, TT-2PPAB and DFBT-2PPAB, with an acceptor-donor-acceptor configuration for photovoltaic studies. Among them, in combination with [6,6]-phenyl-C71 butyric acid methyl ester (PC71BM) acceptor, TT-2PPAB exhibits a moderate power conversion efficiency (PCE) of 3.11% due to an Eloss of 0.48 eV, which is smaller than the empirical limit of 0.6 eV. Based on the electrochemistry and theoretical calculations, we revealed that the efficient photovoltaic performance of the TT-2PPAB-based device can be ascribed to the sufficiently deep LUMO level of TT-2PPAB for charge transfer to PC71BM.