Kandpal Suchita, Ghosh Tanushree, Rani Chanchal, Tanwar Manushree, Sharma Meenu, Rani Sonam, Pathak Devesh K, Bhatia Ravi, Sameera I, Jayabalan Jesumony, Kumar Rajesh
Materials and Device Laboratory, Department of Physics, Indian Institute of Technology Indore, Simrol-453552, India.
Department of Physics, Guru Jambheshwar University of Science & Technology, Hisar-125001, India.
ACS Mater Au. 2022 Feb 2;2(3):293-300. doi: 10.1021/acsmaterialsau.1c00064. eCollection 2022 May 11.
A dual purpose solid state electrochromic diode has been fabricated using polythiophene (P3HT) and ethyl Viologen (EV), predoped with multiwalled carbon nanotubes (MWCNTs) and MoS. The device has been designed by considering two important aspects, first, the complementary redox activity of P3HT and EV and second, the electron holding properties of MoS and MWCNTs. The latter is found to enhance the electrochromic performance of the solid state device. On the other hand, the complementary redox nature gives the asymmetric diodic I-V characteristic to the device which has been exploited to use the electrochromic device for rectification application. The MoS nanoflower and MWCNTs are synthesized by one-step hydrothermal and pyrolysis techniques and well characterized by scanning electron microscopy (SEM), X-ray analysis (XRD), and Raman spectroscopy. Electrochromic properties of the device have been studied in detail to reveal an improvement in device performance in terms of faster speed and high coloration efficiency and color contrast. In situ bias-dependent Raman spectroscopy has been performed to understand the operation mechanism of the electrochromic diode which reveals (bi-)polaron formation as a result of dynamic doping eventually leading to color change. A half-wave rectifier has been realized from the electrochromic diode which rectifies an AC voltage of frequency 1 Hz or less making it suitable for low frequency operation. The study opens a new possibility to design and fabricate multipurpose frequency selective electrochromic rectifiers.
一种双用途固态电致变色二极管已采用聚噻吩（P3HT）和乙基紫精（EV）制成，它们预先掺杂了多壁碳纳米管（MWCNT）和MoS。该器件的设计考虑了两个重要方面，一是P3HT和EV的互补氧化还原活性，二是MoS和MWCNT的电子保持特性。发现后者可增强固态器件的电致变色性能。另一方面，互补的氧化还原性质赋予器件不对称的二极管I-V特性，该特性已被用于将电致变色器件用于整流应用。MoS纳米花和MWCNT通过一步水热和热解技术合成，并通过扫描电子显微镜（SEM）、X射线分析（XRD）和拉曼光谱进行了充分表征。已详细研究了该器件的电致变色特性，以揭示器件在速度更快、着色效率更高和颜色对比度方面的性能改进。已进行原位偏压相关拉曼光谱研究，以了解电致变色二极管的工作机制，该机制揭示了由于动态掺杂最终导致颜色变化而形成（双）极化子。已从电致变色二极管实现了一个半波整流器，该整流器可整流频率为1 Hz或更低的交流电压，使其适用于低频操作。该研究为设计和制造多功能频率选择性电致变色整流器开辟了新的可能性。
