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Critical impact of gate dielectric interfaces on the trap states and cumulative charge of high-performance organic thin field transistors
摘要： In the operation of OFETs, the electrical properties are strongly dependent on the merits of the constituting layers and the formed interfaces. Here we study the trap states variations at the interface between the organic semiconductor pentacene and polymer insulators. With ZrO2 dielectric modified by polymers and find a 10 × decrease in the density of trap states at the semiconductor/insulator interface, bring about the charge carrier mobility increase from 0.058 cm2/Vs to 0.335 cm2/Vs. In addition, when compare to the thicker films at the same applied gate voltage, the thinner film would lead to enhanced coupling capability and more charges cumulative cumulated at the channel region, which is pivotal for optimizing the performance of OFETs. The results prove that the property of the insulator layer could impact largely on the device performance.
关键词： Organic thin film transistor,Cumulative charge,Insulator/semiconductor interface,Trap states
更新于2025-09-23 15:23:52
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Shallow and Deep Trap States Passivation for Low-Temperature Processed Perovskite Solar Cells
摘要： While perovskite solar cells (PSCs) have emerged as promising low-cost solar power generators, most reported high-performance PSCs employ electron transport layers (ETLs, mainly TiO2) treated at high temperatures (≥450 °C), which may eventually hinder the development of flexible PSCs. Meanwhile, the development of low-temperature processed PSCs (L-PSCs) possessing performance levels comparable to that of high-temperature processed PSCs has actively been reported. In this study, L-PSCs with improved long-term stability and negligible hysteresis were developed through the effective passivation of shallow and deep traps in organic-inorganic hybrid perovskite (OIHP) crystals and at the ETL/OIHP interface. L-PSCs with alkaline chloride modification achieved state-of-the-art performance among reported L-PSCs (power conversion efficiency (PCE) = 22.6%) with a long-term shelf life. The origin of long-term stability and the efficient passivation of deep traps was revealed by monitoring the trap-state distribution. Moreover, the high PCE of a large-area device (21.3%, 1.12 cm2) were also demonstrated, confirming the uniformity of the modification.
关键词： trap states passivation,low-temperature processed,alkaline chloride modification,perovskite solar cells,long-term stability
更新于2025-09-23 15:21:01
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The influence of fullerene on hysteresis mechanism in planar perovskite solar cells
摘要： Despite the rapid development of perovskite devices, the current density-voltage hysteresis still needs to be conquered. Here, the introduction of PCBM into the active layer of planar perovskite solar cells is carried out and hysteresis-free devices are produced. A photoluminescence blue-shift in PCBM-doped perovskite ?lms is observed. The e?ect of non-radiative recombination is obviously suppressed, and the photoluminescence lifetime is signi?cantly prolonged by 3-fold after PCBM introduction. The roles of PCBM in trap states and hysteresis mechanism are also discussed. This research could provide experimental and theoretical supports for suppressing and eliminating the hysteresis phenomena in perovskite solar cells.
关键词： Hysteresis,Trap states,Planar perovskite solar cells,PCBM
更新于2025-09-23 15:19:57
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The diverse passivation effects of fullerene derivative on hysteresis behavior for normal and inverted perovskite solar cells
摘要： [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is usually used to passivate the trap states and ion defects for suppressing hysteresis in both normal and inverted perovskite solar cells. Here, we find that the normal cell with the perovskite film fabricated on the PCBM film shows an evident hysteresis, while the inverted cell with the perovskite film covered by the PCBM film shows nearly no hysteresis, and the PCBM-Perovskite interface impacts on the hysteresis vastly. The poor PCBM surface wettability results in an inefficient carrier extraction at the interface and a red-shift of photoluminescence emission for the perovskite film coated on the PCBM film, which results from the plentiful trap states and ion defects inside the perovskite film due to its poor crystallization. Thus, the trapping/de-trapping processes and slow ion migration eventually lead to the hysteresis. For the perovskite film covered by the PCBM film, due to the good wettability of the perovskite film, PCBM molecules easily permeate into the perovskite film to passivate the trap states and ion defects, which improves the carrier extraction and thus eliminates the hysteresis of the inverted cell.
关键词： Hysteresis behavior,Trap states,Perovskite solar cells,Ion migration,Carrier extraction,PCBM
更新于2025-09-23 15:19:57
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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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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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Enhanced performance of tin halide perovskite solar cells by addition of hydrazine monohydrobromide
摘要： Although tin-based perovskite has been considered as a kind of potential environmentally-friendly photovoltaic materials, the tin-based perovskite solar cells are limited due to their poor stability and low conversion efficiency mainly tracing to the oxidation from Sn2t state in tin-based perovskite films. Herein, a facile reductive approach is developed to suppress the oxidation, in which tiny amount of hydrazine monohydrobromide is doped into FASnI3-based perovskite precursor solution as a reducing agent. Our results demonstrate that the addition of hydrazine monohydrobromide could reduce the defects and trap states in perovskite by inhibiting formation of tetravalent tin, and increase the open circuit voltage by widening the bandgap of perovskite. As a consequence, the best optimized perovskite solar cell achieves an excellent power conversion efficiency of 7.81%, which represented a 39.5% improvement compared to the best reference device. The optimized devices display stabilized power output near the maximum power point and negligible hysteresis effect.
关键词： Trap states,Defect,Hydrazine monohydrobromide,Lead-free,Tin-based perovskite solar cell
更新于2025-09-23 15:19:57
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Ligand-Assisted Reconstruction of Colloidal Quantum Dots Decreases Trap State Density
摘要： Increasing the power conversion efficiency (PCE) of colloidal quantum dot (CQD) solar cells has relied on improving the passivation of CQD surfaces, enhancing CQD coupling and charge transport, and advancing device architecture. The presence of hydroxyl groups on the nanoparticle surface, as well as dimers—fusion between CQDs—has been found to be the major source of trap states, detrimental to optoelectronic properties and device performance. Here, we introduce a CQD reconstruction step that decreases surface hydroxyl groups and dimers simultaneously. We explored the dynamic interaction of charge carriers between band-edge states and trap states in CQDs using time-resolved spectroscopy, showing that trap to ground-state recombination occurs mainly from surface defects in coupled CQD solids passivated using simple metal halides. Using CQD reconstruction, we demonstrate a 60% reduction in trap density and a 25% improvement in charge diffusion length. These translate into a PCE of 12.5% compared to 10.9% for control CQDs.
关键词： trap states,dimers,surface defects,photovoltaics,Quantum dots
更新于2025-09-19 17:13:59
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Extent of Shallow/Deep Trap States beyond the Conduction Band Minimum in Defect-Tolerant CsPbBr <sub/>3</sub> Perovskite Quantum Dot: Control over the Degree of Charge Carrier Recombination
摘要： Perovskite quantum dots (PQDs) are known to be defect tolerant possessing clean band-gap with optically inactive benign defect states. However, we show that there exists significant deep trap states beyond conduction band minimum, although the extent of shallow trap states is observed to be minimal. Extent of deep trap states beyond conduction band minimum seem to significant in PQD, however the extent is less than even optically robust CdSe and InP based core/alloy-shell QDs. In-depth analyses based on ultrafast transient absorption and ultrasensitive single particle spectroscopic investigations decode the underlying degree of charge carrier recombination in CsPbBr3 PQD which are quite important for energy applications.
关键词： Perovskite quantum dots,ultrafast transient absorption,defect tolerant,single particle spectroscopy,charge carrier recombination,trap states
更新于2025-09-19 17:13:59