MoS2 nano-flower incorporation for improving organic-organic solid state electrochromic device performance

Abstract A solid state electrochromic device has been fabricated using molybdenum disulfide (MoS2) doped Ethyl viologen (EV) and polythiophene (P3HT) layers. The MoS2 nano flower has been synthesized by one-step hydrothermal method and characterized by electron spectroscopy, X-ray diffraction and Raman spectroscopy. The prepared solid state electrochromic device shows its improved electrochromic performance like switching speed, cycle life and coloration efficiency while showing color modulation between magenta and blue colors. A very small external (±1.4 V) bias is sufficient to switch the device very quickly by taking time as low as 400 ms and shows the transmittance modulation of 42%. It is proposed that the MoS2 having graphene like 2D layered structure and the weak van der Waals force present between layers facilitates large amount of charge movement between the film and electrolyte, hence, promoting the high transfer rate of electrons, which plays the key role to enhance the performance of electrochromic device. Incorporation of MoS2 makes one of the most efficient devices in the family of polythiophene-viologen based devices and opened up a new avenues for other hybrid electrochromic device as graphene alternatives by exhibiting coloration efficiencies of as high as 580 cm2/C.