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Effect of the Interface Improved by Self-Assembled Aromatic Organic Semiconductor Molecules on Performance of OLED
摘要： This work focuses on characterization the performance of enhanced interface of organic light emitting diode (OLED) device by Self-assembled Monolayer (SAM) technique. SAM technique is popular in order to overcome the weak bonding at the organic/inorganic interface in OLED. New generation of SAM molecules, phenyl-benzoic-acid (PBA, 4-(9H-carbazol-9-il) benzoic acid (MZ39), 4-(2,5-di-2thienyl-1H-pyrrol-1-il) benzoic acid (MZ25) were coated on between Indium Tin Oxide (ITO). The two con?guration of ITO/SAM/TPD/Al and ITO/TPD/Al diode were fabricated as hole-only device to show the contribution of SAM layer on the hole mobility calculated by Space Charge Limited Current (SCLC) technique. The optical characterization of OLED devices with con?guration ITO/TPD/Alq3/Al and ITO/SAM/TPD/Alq3/Al was performed to see the effect of aromatic SAM molecules on the luminance and quantum ef?ciency. Especially, the SAM modi?ed OLED has a maximum luminance of 397 cd m?2. All devices containing SAM layer showed better performance than reference one.
关键词： Indium Tin Oxide (ITO),quantum efficiency,OLED,luminance,Space Charge Limited Current (SCLC),Self-assembled Monolayer (SAM)
更新于2025-09-23 15:21:01
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High charge carrier mobility in solution processed one-dimensional lead halide perovskite single crystals and their application as photodetectors
摘要： Organic inorganic hybrid metal halide perovskites have emerged as promising candidates for photovoltaics and light-emitting diodes. Recently, interest has been growing in the properties of low-dimensional metal halide perovskites, and one-dimensional versions with strong quantum confinement have demonstrated highly efficient broadband luminescence. Nevertheless, the charge transport mechanism in these low dimensional perovskites remains unclear. In this work, we characterised the charge mobility in one-dimensional perovskite single crystals using a space charge limited current method. Temperature dependent charge mobility measurements indicated that localized polarons at high temperature are replaced by delocalized polarons at low temperature with extended states in the polaronic band. A minimum mobility of 4.51 cm2/Vs was measured at room temperature. UV photodetectors based on these crystals show an ultrahigh photoresponsivity of 132.3 A W-1. These findings show the promise of high mobility low dimensional perovskite materials for optoelectronic applications.
关键词： space charge limited current,low-dimensional,charge transport,photodetectors,organic-inorganic hybrid metal halide perovskites
更新于2025-09-19 17:13:59
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The role of moisture in the preparation for efficient planar perovskite solar cells
摘要： Perovskite solar cells (PSC) have achieved a certificated efficiency of 25.2% within the past few years. Among effective methods, one of the most effective approaches obtaining highly-efficient PSCs is the moisture-assisted annealing process. However, the role of moisture in the preparation of high-performance PSCs is under intense debate. Herein the critical effect of moisture in the preparation of efficient Formamidinium (FA) based PSCs with improved-quality perovskite films is systematically investigated based on diverse characterizations. Consequently, the optimal amount of moisture is determined at 50% relative humidity (RH) which produces perovskite films of higher quality with larger and uniform grains size in comparison to the control films prepared in the glovebox. Specifically, prolonged lifetime, reduced defects densities and higher light harvesting capability of perovskite films annealed in 50RH% are confirmed by the photoluminescence (PL), the time-resolved PL (TRPL), the space charge limited current (SCLC) and the confocal laser scanning microscopy (CLSM), respectively. These results indicate the environments with a controlled level of moisture is preferable for achieving high-quality perovskite films and the compatibility of fabricating highly-efficient PSCs under ambient conditions with controlled moisture for future industrial mass production.
关键词： defects density,two-step deposition,Planar perovskite solar cells,moisture,space-charge-limited current
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Kerala, India (12–14 June 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Measurement of hole mobility in P3HT based photovoltaic cell using space charge limited current method
摘要： Mobility of carriers is one of the pivotal parameters characterizing any semiconducting material and it is important for organic semiconductors too. The mobility of organic semiconductors remains far less when compared to inorganic counterparts and hence attempts in the direction improvise it carries tremendous significance. This paper investigates the positive charge carriers transport properties in a bulk heterojunction organic photovoltaic cell using two different Anode Buffer Layers (PEDOT:PSS and MoO3). The method of Space Charge Limited Current (SCLC) is used to compute the hole mobilities and also the values are compared. The values obtained with PEDOT:PSS and MoO3 as HTLs are 1.043x10-4 cm2 V-1S-1 and 1.357x10-4 cm2V-1S-1 respectively. It is seen that the device with higher carrier mobility exhibits better performance.
关键词： PEDOT:PSS,hole mobility,space charge limited current,MoO3,photovoltaic cell,P3HT
更新于2025-09-12 10:27:22
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Effect of space charge limited current on performance of organic field-effect transistors
摘要： The crucial parameter that determines the performance of a semiconductor material in organic field-effect transistors (OFETs) is the charge carrier mobility. The conventional method of its determination based on Shockley’s equations can lead to incorrect mobility evaluation due to contact effects. Particularly, in the common staggered OFET architecture (top-contact bottom-gate or bottom-contact top-gate), the space-charge limited current (SCLC) effect in the active layer under/above the source and drain contacts decreases the source-drain current. In this work, we model the effect of SCLC under/above the source and drain electrodes on the OFET apparent mobility (i.e., calculated from the device characteristics) and apparent threshold voltage for different active layer thickness and intrinsic mobility anisotropy. For the saturation regime, we derived simple analytical expressions for transfer characteristics and apparent mobility. Our modeling shows that the apparent OFET mobility is more than five times lower than the intrinsic one for the active layer thicker than 100 nm with mobility anisotropy (along vs across the active layer) higher than 100. While the SCLC effect does not change the apparent threshold voltage, it reveals itself as a kink at near zero voltage in the output characteristics. The proposed model gives analytical expressions for the transfer characteristics and apparent mobility as explicit functions of the intrinsic mobility and the device parameters in the saturation regime and as implicit functions in the linear regime. Our findings provide guidelines for accurate evaluation of the intrinsic mobility in OFETs fabricated in the staggered architecture and for further improvement of OFET performance.
关键词： Organic field-effect transistors,Organic thin-film transistors,Space charge limited current,Contact effects,Modeling
更新于2025-09-11 14:15:04
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Field Effect in PbSnTe:In Films with Low Conductivity in the Mode of Injection from Contacts and Space-Charge Limitation of the Current
摘要： At T = 4.2 K, a strong change (up to 4 times) in the space-charge-limited current (SCLC) is observed for the first time at samples based on semi-insulating PbSnTe:In films grown by molecular-beam epitaxy on BaF2(111) substrates. The obtained results agree with experiments on the effect of treatment of the surface of PbSnTe:In films on the space-charge-limited current with a variation in the current to 103 times or more. At a qualitative level, the model is considered which assumes the substantial contribution of localized surface states to space charge formed in the mode of space-charge-limited current due to the injection of charge carriers from contacts.
关键词： field effect,surface states,molecular-beam epitaxy,space-charge-limited current,PbSnTe:In films
更新于2025-09-10 09:29:36