Gtari Wala, Radaoui Moufid, Ben Fredj Amel, Romdhane Samir, Egbe Daniel Ayuk Mbi, Bouchriha Habib
Faculté des Sciences de Gafsa, Département de Physique, Université de Gafsa, Campus Sidi Ahmed Zarouk, Gafsa 2112, Tunisie.
Laboratoire Matériaux Avancés et Phénomènes Quantiques, Faculté des Sciences de Tunis, Université de Tunis El Manar, Campus Universitaire, Tunis 2092, Tunisia.
ACS Omega. 2025 Aug 14;10(33):37791-37802. doi: 10.1021/acsomega.5c04621. eCollection 2025 Aug 26.
This paper reports the use of P18-8, a novel conjugated polymer combining poly-(1,4-phenylene-ethynylene) and poly-(1,4-phenylene-vinylene), in the fabrication of an organic diode with the structure ITO/PEDOT:PSS/P18-8/LiF/Al. The electrical properties of the fabricated device were characterized using impedance spectroscopy across a frequency range of 100 Hz to 1 MHz at various applied voltages. The current density-voltage (-) characteristic exhibited ohmic behavior at low applied voltages, while at higher voltages, it conformed to the space charge limited current (SCLC) theory. The impedance (*) of the device, as a function of frequency and bias voltage, was modeled using a single parallel resistor and capacitor network connected in series with a resistance. The dielectric loss (ε″) decreased with increasing frequency for all applied voltages, mainly due to deformation and relaxation polarization effects. Peaks in the dielectric loss tangent (tan-(δ)) around 10 Hz indicated dipolar polarization behavior. The lower values of the real part of the complex electric modulus (') observed at the low-frequency region were attributed to the long-range mobility of charge carriers. Additionally, the imaginary part of the complex electric modulus (″) reached its maximum value at all applied voltages, resulting in a peak at a specific frequency. The frequency-dependent conductance (σ) demonstrated a power-law dependence (σ ∝ ω), where the value of ″s″ increased with applied voltage and exceeded unity. Furthermore, we report the observed magnetoconductance (MC) under a weak static magnetic field (<1 T) at room temperature. Positive MC is observed and reaches up to 0.8% at a magnetic field of 500 mT at room temperature. It is found that with the increase of the voltage, the MC effect decreases. Our analysis of the experimental data was conducted within the framework of the electron-hole (e-h) pair model, employing the Stochastic Liouville Equation.
本文报道了一种新型共轭聚合物P18 - 8的应用，该聚合物由聚（1,4 - 亚苯基乙炔）和聚（1,4 - 亚苯基亚乙烯基）组合而成，用于制备结构为ITO/PEDOT:PSS/P18 - 8/LiF/Al的有机二极管。在不同的施加电压下，使用阻抗谱在100 Hz至1 MHz的频率范围内对制备器件的电学性质进行了表征。电流密度 - 电压（I - V）特性在低施加电压下呈现欧姆行为，而在较高电压下，符合空间电荷限制电流（SCLC）理论。该器件的阻抗（Z）作为频率和偏置电压的函数，使用与一个电阻串联的单个并联电阻和电容网络进行建模。对于所有施加电压，介电损耗（ε″）随频率增加而降低，这主要归因于形变和弛豫极化效应。在10 Hz左右的介电损耗正切（tanδ）峰值表明存在偶极极化行为。在低频区域观察到的复电模量（M′）实部的较低值归因于电荷载流子的长程迁移率。此外，复电模量（M″）的虚部在所有施加电压下都达到其最大值，从而在特定频率处产生一个峰值。频率相关的电导率（σ）表现出幂律依赖性（σ ∝ ω^s），其中“s”的值随施加电压增加且超过1。此外，我们报道了在室温下弱静磁场（<1 T）下观察到的磁导率（MC）。观察到正的MC，在室温下500 mT的磁场中达到高达0.8%。发现随着电压的增加，MC效应减小。我们在电子 - 空穴（e - h）对模型的框架内，采用随机刘维尔方程对实验数据进行了分析。
