| Host-guest intercalation chemistry is an emerging research field with implications in the development of novel materials for a wide variety of real-world applications. As such, the intercalation chemistry of the two dimensional layered molybdenum diselenide (MoSe2) has been explored. MoSe2 has been intercalated with a variety of guest species such as solid polymer electrolytes, electronically conductive polymers, and small molecules. This was achieved by first treating the MoSe2 with an excess of n-BuLi to form the lithiated phase of MoSe2 (Li0.7MoSe 2). The Li0.7MoSe2 exfoliates readily in water or N-methylformamide (NMF) to yield single layers of MoSe2. Addition of solutions or suspensions of guest species to the single layers result in the formation of novel sandwiched compounds. These guest species include solid polymer electrolytes (SPE) such as poly(ethylene oxide) (PEO), poly(vinyl pyrrolidone) (PVP), methyl cellulose (MCel), poly[oxymethylene-(oxyethylene)] (POMOE), and poly[bis-(methoxyethoxyethoxy)phosphazene] (MEEP), electronically conductive polymers such as polyaniline (PANI), poly(N-methylaniline) (PMA), poly(2-ethylaniline) (PEA) and poly(-propylaniline) (PPA), and small molecules such as glycine, ferrocene and 7,7,14,14-Tetramethy1-1,4,8,11-tetrazacyclotetradeca-4,11-dine (TTCD).;Analysis of the materials has been done by Powder X-ray Diffractometry (XRD), Fourier Transform Infra Red Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) where applicable. In the XRD spectra, the dramatic increase of the interlayer spacing values of the resulting compounds suggest that all of the guest species mentioned above have been intercalated into the MoSe2 layers. Thermal stabilities and stoichiometries of SPE/MoSe2 were determined by TGA. The guest-host interactions of the polymer/MoSe2 intercalates have been studied by FT-IR and DSC; the red shifts in the FT-IR spectra and the glass transition temperature (Tg) shifts of polymers in DSC reveal that the mechanical motions of the polymers were confined by the MoSe2 layered host. In addition, the blue shifts in the FT-IR spectra suggest that redox reactions may occur between the guests and the host. Electronic conductivities were measured using the four-probe van der Pauw technique. Compared to the conductivity of 2H MoSe2 the increase in conductivity of 'restacked MoSe 2' indicates the conversion from the semiconductor (2H form) to the conductor (1T form). Among the electronically conductive polymer/MoSe 2 intercalates, PMA/MoSe2 intercalate showed better results in conductivities compared to PANI/MoSe2, PEA/MoSe2, and PPA/MoSe2 intercalates. Ionic conductivities of MEEP, (MEEP) 4LiCF3SO3 and (MEEP)4LiCF3SO 3/MoSe2 intercalate were investigated through alternating current (AC) impedance spectroscopy. |
