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High-Performance Inverted Perovskite Solar Cells using 4-Diaminomethylbenzoic as Passivant
摘要： Grain boundaries (GBs) and interface passivation of perovskite films impact the efficiency and stability of perovskite solar cells (PSCs) dramatically. Here, an efficient passivation strategy using 4-Diaminomethylbenzoic (4-DA) followed by thermal annealing treatment is proposed to improve the performance of PSCs. We have systemically investigate the impact of 4-DA on the physical properties of perovskite layer and corresponding performance of the inverted PSCs. The results show that the contact between crystalline grains are improved, and high quality MAPbI3 films are successfully prepared, which result in the elimination of the trap states and enhanced performance of the devices. The highest power conversion efficiency (PCE) of 20.58% is achieved in this work. Meanwhile, the devices show enhanced stability and the average PCE values almost maintained the same after 168 hours storage without any encapsulation. The passivation method developed in this work shows a novel strategy toward the fabrication of inverted PSCs with high efficiency and high stability.
关键词： passivation strategy,trap states,inverted perovskite solar cells
更新于2025-09-23 15:19:57
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Unsymmetrical Small Molecules for Broadband Photoresponse and Efficient Charge Transport in Organic Phototransistors
摘要： Organic photosensitizers have been investigated as effective light sensing elements that can promote strong absorption with high field-effect mobility in organic phototransistors (OPTs). In this study, a novel organic photosensitizer is synthesized to demonstrate broadband photoresponse with enhanced electrical performance. An unsymmetrical small molecule of a solubilizing donor(Dsol)-acceptor(A)-dye donor(Ddye) type connected with twisted conjugation system is designed for broadband detection (ranging from 250 nm to 700 nm). This molecule has high solubility, thereby facilitating the formation of uniformly dispersed nanoparticles in an insulating polymer matrix, which is deposited on top of OPT semiconductors by a simple solution process. The broadband photodetection shown by the organic photosensitizer is realized with improved mobility by close to an order of magnitude and high on/off current ratio (~105) of the organic semiconductor. Furthermore, p-type charge transport behavior in the channel of the OPT is enhanced through the intrinsic electron-accepting ability of the organic photosensitizer, caused by the unique molecular configuration. These structural properties of organic photosensitizers contribute to an improvement in broadband photosensing systems with new optoelectronic properties and functionalities.
关键词： Photosensitizer,Surface doping,Broadband detection,Phototransistor,Charge trap
更新于2025-09-23 15:19:57
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The influence of the electron transport layer on charge dynamics and trap-state properties in planar perovskite solar cells
摘要： Despite the outstanding photovoltaic performance of perovskite solar cells, the correlation between the electron transport layer and the mechanism of photoelectric conversion is still not fully understood. In this paper, the relationship between photovoltaic performance and carrier dynamics is systematically studied in both TiO2- and SnO2-based planar perovskite devices. It is found that the different electron transport layers result in distinct forward scan results and charge dynamics. Based on the charge dynamics results, the influence of the electron transport layer on charge carrier transport and charge recombination is revealed. More importantly, the trap-state density is characterized, which is proven to be related to the charge carrier dynamics and the specific hysteresis behaviour in the perovskite solar cells. The present work would provide new insights into the working mechanisms of electron transport layers and their effect on hysteresis.
关键词： electron transport layer,hysteresis,charge dynamics,perovskite solar cells,trap-state properties
更新于2025-09-23 15:19:57
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Multifunctional Phosphorusa??Containing Lewis Acid and Base Passivation Enabling Efficient and Moisturea??Stable Perovskite Solar Cells
摘要： Multiple-cation lead mixed-halide perovskites (MLMPs) have been recognized as ideal candidates in perovskite solar cells in terms of high efficiency and stability due to decreased open-circuit voltage loss and suppressed yellow phase formation. However, they still suffer from an unsatisfactory long-term moisture stability. In this study, phosphorus-containing Lewis acid and base molecules are employed to improve device efficiency and stability based on their multifunction including recombination reduction, phase segregation suppression, and moisture resistance. The strong fluorine-containing Lewis acid treatment can achieve a champion PCE of 22.02%. Unencapsulated and encapsulated devices retain 63% and 80% of the initial efficiency after 14 days of aging under 75% and 85% relative humidity, respectively. The better passivation of Lewis acid implies more halide defects than Pb defects at the MLMP surface. This unbalanced defect type results from phase segregation that is the synergistic effect of Cs and halide ion migrations. Identifying defect type based on different passivation effects is beneficial to not only choose suitable passivators to boost the efficiency and slow down the moisture degradation of MLMP solar cells, but also to understand the mechanism of defect-assisted moisture degradation.
关键词： lewis acids,trap passivation,moisture stable solar cells,multiple-cation lead mixed-halide perovskites,phase segregation,lewis bases
更新于2025-09-23 15:19:57
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Resolving spatial and energetic distributions of trap states in metal halide perovskite solar cells
摘要： We report the profiling of spatial and energetic distributions of trap states in metal halide perovskite single-crystalline and polycrystalline solar cells. The trap densities in single crystals varied by five orders of magnitude, with a lowest value of 2 × 1011 per cubic centimeter and most of the deep traps located at crystal surfaces. The charge trap densities of all depths of the interfaces of the polycrystalline films were one to two orders of magnitude greater than that of the film interior, and the trap density at the film interior was still two to three orders of magnitude greater than that in high-quality single crystals. Suprisingly, after surface passivation, most deep traps were detected near the interface of perovskites and hole transport layers, where a large density of nanocrystals were embedded, limiting the efficiency of solar cells.
关键词： spatial distribution,solar cells,metal halide perovskite,energetic distribution,trap states
更新于2025-09-23 15:19:57
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Tailoring optoelectronic properties of CH3NH3PbI3 perovskite photovoltaics using al nanoparticle modified PC61BM layer
摘要： In photovoltaics, light harvesting is one of the critical factors for the enhancement of power conversion efficiency (PCE). Photon harvesting can be carried out by various methods in perovskite photovoltaic. The improved light harvesting can also be achieved by trapping the light by incorporating metallic nanoparticles at the interface or in the perovskite active layer itself. Either light is absorbed or scattered by metallic nanoparticles depending on the particle size. When light is absorbed by the nanoparticles (size < 20 nm), it behaves like a sub-wavelength antenna due to localized surface plasmon resonance (LSPR) excitation and hence near field effect of plasmonic particle will be interacting to CH3NH3PbI3 active layer. Larger particles (> 20 nm) act as sub-wavelength scattering centers of light and help in trapping incident light. In order to make use of dual effect poly-dispersed spherical aluminium nanoparticles (AlNPs) (size – 20–70 nm) were incorporated in the CH3NH3PbI3 perovskite solar cell at the PC61BM/Al electrode interface. As a result, there is an increase in the optical absorption in the AlNPs embedded device. A detailed study of optical absorption, absorbed light emission characteristics charge trap density and carrier concentration studies, photovoltaic property measurements indicates, improvement in power conversion efficiency arise due to enhancement in JSC. Evaluated device properties indicate that enhancement in JSC arises due to improvement in the active layer photon absorption by both scattering and plasmonic effect in addition to reduced series resistance.
关键词： Trap states,Organic-inorganic halide perovskite solar cell,Ultraviolet plasmonic resonance,Plasmonic nanoparticle current density,Metal nanoparticles
更新于2025-09-23 15:19:57
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Towards Sympathetic Cooling of Highly Charged Ions by Laser-Cooled Ca+ Ions
摘要： The long-term goal of the Penning trap system for the heavy ion accelerator named RAON in Korea is to obtain an order of magnitude higher mass accuracy for short-lived rare isotopes. For that purpose, we are developing a sympathetic cooler for highly charged ions by exploiting laser-cooled Ca+ ions. We installed a prototype octagon chamber with a calcium atom source, a Paul trap, and a helical resonator for the high-voltage RF supply. The laser system is composed of three extended cavity diode lasers (423, 397, 866 nm) plus one UV diode laser (375 nm). The optical frequency stabilization setup is made up of a wavelength meter, a multichannel fiber switch and a PXI system with an 8-channel analog output module. After having obtained a resonant ionization signal from the calcium atomic beam, we applied the RF voltage to the trap electrodes and illuminated the cooling lasers at the center of the trap. We successfully observed a laser-cooled ion bunch and a linearly aligned ion string by using imaging optics and an electron multiplying charge coupled device (EMCCD) camera. In addition to the experimental effort, we performed a simulation study for cooling 132Sn10+ ions inside a laser-cooled 40Ca+ Coulomb crystal by using a parallel computation technique.
关键词： Ion trap,Sympathetic cooling,Laser cooling
更新于2025-09-23 15:19:57
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Enhanced device performance with passivation of the TiO <sub/>2</sub> surface using a carboxylic acid fullerene monolayer for a SnPb perovskite solar cell with a normal planar structure.
摘要： Research on tin-lead (SnPb) perovskite solar cells (PSCs) have gained popularity in recent years due to their low bandgap which could be applied to tandem solar cells. However, most of the work are based on inverted PSCs using PEDOT:PSS as the hole transport layer as the normal structure PSCs show lower efficiency. In this work, the reason behind the low efficiency of normal structure SnPb PSCs is elucidated and the method to overcome the problem has been attempted through surface passivation. In the case of normal PSCs, at the interface between titania layer and SnPb perovskite there are many carrier traps observed originating from Ti-O-Sn bonds. In order to avoid the direct contact between titania and SnPb perovskite layer, the titania surface is passivated with carboxylic acid C60 resulting in efficiency increase from 5.14 % to 7.91 %. This will provide a direction of enhancing the efficiency of normal structure SnPb PSCs through heterojunction engineering.
关键词： passivation,Perovskite solar cells,Tin,titania,Lead,trap density,interface
更新于2025-09-23 15:19:57
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Effect of thioglycolic acid molecules on luminescence properties of $$\hbox {Ag}_2$$Ag2S quantum dots
摘要： For monoclinic Ag2S nanocrystals (quantum dots, Ag2S/TGA QDs), the correlation between their luminescence properties and aspects of their passivation by thioglycolic acid (TGA) molecules is considered. The features of quantum confinement effect in the QDs absorption and photoluminescence spectra are analyzed for Ag2S QDs with an average size of 1.7–3.1 nm. We show that, in various conditions of passivation of QDs interfaces, the luminescence mechanism of Ag2S/TGA QDs is switched from recombination luminescence in the 870–1000 nm region to exciton luminescence with a band maximum at 620 nm. By means of FTIR spectra, two major types of interactions between TGA molecules and Ag2S QDs, arising due to changing the [Ag+]:[S2?] ratio from 1:0.9 to 1:1.43, are determined. Exciton luminescence (620 nm) occurs in case of using TGA as the sulfur source in Ag2S crystallization and the interface passivation agent, with [Ag+]:[S2?] = 1:1. The analysis of the FTIR spectra indicates bonding of TGA with the Ag2S surface by both thiol and carboxylic groups in this case. With increasing the sulfur concentration in the synthesis of Ag2S/TGA QDs, the exciton luminescence is suppressed. The employment of Na2S as the sulfur source in Ag2S crystallization with TGA acting as the surface passivation agent promotes the formation of recombination centers for IR luminescence. In this case, analysis of the FTIR spectra indicates passivation of Ag2S QDs by TGA molecules due to adsorption of thiol groups. It is found that the photodegradation or IR luminescence of Ag2S/TGA QDs upon exposure to exciting radiation is due to the photolysis of Ag2S nanocrystals with formation of luminescence quenching centers as well as due to photodestruction of TGA molecules.
关键词： Size dependence,Thioglycolic acid,Interaction mechanism,FTIR spectra,Trap state luminescence,Silver sulfide,Luminescence properties
更新于2025-09-23 15:19:57
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The role of interfacial H-bonding in electrical properties of UV-cured resin filled with hydroxylated Al2O3 nanoparticles
摘要： Surface hydroxylation of crude Al2O3 (c-Al2O3) nanoparticles by H2O2 was conducted to tailor the electrical properties of UV-cured resin. The hydroxyl groups on Al2O3 particles were designed to establish hydrogen bonding between hydroxyl and carboxyl with that of UV/c-Al2O3 composites at the same filler content. It was found that the addition of 0.5 wt % h-Al2O3 increases the AC breakdown strength and volume resistivity by 15.5 % and 367.9 %, respectively. Our results suggest that the hydroxylation is an efficient way to improve the electrical properties of UV-cured resin nanocomposites, thus promoting stereolithography 3D printing in application of electrical and electronic field.
关键词： Stereolithography,Interfacial region,Hydrogen bonding,Nanocomposites,Interfacial strength,Trap levels,Electrical properties
更新于2025-09-23 15:19:57