Chemistry Colloquium | Chanchal Chakraborty
September 25 @ 11:00 am - 12:00 pm
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Title: Interplay of Electrochromic Parameters and Color Hue in Metallo-Supramolecular Architectures
Speaker: Chanchal Chakraborty
Department of Chemistry, BITS Pilani Hyderabad Campus
Abstract: Electrochromism is an exclusive non-emissive chromic effect which can reversibly amend their optical properties controlled by external bias.1 The commercially demanding display technology is mostly used in smart windows, information displays, e-papers, advertise boards etc.2 The commercial electrochromic device (ECD) applications of EC materials depend on various EC parameters like, color fastness, power and coloration efficiency, optical memory and vivid color modulation. The color fastness or the fast switching regulates the EC applications in smart dynamic devices, while the high optical memory in ECDs can provide power efficiency. Moreover, the development in color modulation can provide multicolor hue for new generation display technologies.
The metallo-supramolecular polymer (MSP) architectures are the newly added 4th generation EC materials in this regard.2-3 The MSPs are generally the faster switchable EC materials than the commercially available metal oxide-based EC materials as their switching times are usually ~3-5 s range. However, modern dynamic needs faster EC materials with proficient power
Herein, we have synthesized a purple-colored Fe(II)-containing MSP (polyFe) as a potential EC material and subsequently fabricated nanostructured of polyFe by controlled counter anion exchange which another polymer like sodium polystyrene sulfonate (PSS)4 or modified nanoclays (HNT)5 to improve the switching time. An electrochromic hyperbranched MSPs are also prepared to enhance the switching times.6 On the other hand, insertion of charge trapping nanoparticles like MoS2 QDs can effectively extend the optical memory in bleached state.
Again, electrochromic hyperbranched metal-complex nanosheet comprising a three arm terpyridine based ligand and Fe(II) metal ion by interfacial polymerization can provide a good balance between EC memory and color fastness.7 We have also fabricated ECDs with multicolored hue8 or transmissive to blackish-green NIR electrochromism9 to demonstrate the vivid color modulation in ECDs.
1. Motomer R. J. Chem. Soc. Rev. 1997, 26, 147-156.
2. Higuchi M. J. Mater. Chem C 2014, 2, 9331-9341.
3. C. Chakraborty et al. J. Mater. Chem C 2016, 4, 9428-9437.
4. Roy, S.; Chakraborty C. J. Mater. Chem C 2019, 7, 2871-2879.
5. Roy, S.; Chakraborty C. Sol. Energy Mater. Sol. Cell 2020, 208, 110392.
6. Bera M. K.; Chakraborty C. et al. Macromol. Rapid. Commun. 2018, 39, 1800415.
7. Roy, S.; Chakraborty C. ACS Appl. Mater. Interfaces 2020, 12, 35181-35192.
8. Roy, S.; Chakraborty C. ACS Appl. Electron. Mater. 2019, 1, 2531-2540.
9. Roy, S.; Chakraborty C. Chem. Commun. 2021, 57, 7565-7568.
Meeting ID: 919 0721 4649 Passcode: HU962Zrl