Lyotropic Liquid-Crystalline Mesophase of Lithium Triflate–Nonionic Surfactant as Gel Electrolyte for Graphene Optical Modulator

Abstract

Lithium salt (noncoordinating anions, such as lithium triflate (Ltf)) gel electrolytes may be key for the practical use of electrochemical devices. We introduce a new lyotropic liquid-crystalline (LLC) mesophase using Ltf, a small amount of water (as low as 1.3 water per Ltf), and nonionic surfactant (C 18 H 37 (OCH 2 CH 2 ) 10 OH, C 18 E 10 ). The LLC phase forms over a broad range of Ltf/C 18 E 10 mole ratios, 2−18. The clear ethanol solution of the ingredients can be either directly spin-coated over a glass substrate to form a gel phase or it can be prepared as a gel by mixing Ltf, water, and C 18 E 10 . The mesophase leaches out surfactant molecules at low salt concentrations, but at a salt/surfactant mole ratio of above 8, the phase is homogeneous with a cubic mesostructure, fully transparent in the visible optical region, mechanically flexible, and an effective gel electrolyte. We have observed a large electrostatic doping on graphene with the Fermi energy level of ∼1.0 eV using Ltf-C 18 E 10 gel electrolytes. The Ltf-based gels demonstrate better properties than commonly used ionic liquid electrolyte in graphene optical modulators. The stability of the new gel electrolytes and their superior performance make them suitable electrolytes for use in graphene-based optical modulators.

Role of Water in the Lyotropic Liquid Crystalline Lithium Iodide–Iodine–Water–C12E10 Mesophase as a Gel Electrolyte in a Dye-Sensitized Solar Cell

“…In our previous studies, it has been shown that a LiX salt (X could be Cl – , Br – , I – , NO 3 – , and CF 3 SO 3 – ), a nonionic surfactant, and a small amount of water form a lyotropic liquid crystalline (LLC) mesophase and may be used as an electrolyte in various electrochemical cells. − The LiI–I 2 redox couple, used in DSSCs, and 10-lauryl ether (C 12 H 25 (OCH 2 CH 2 ) 10 OH, denoted as C 12 E 10 ) also form an LLC mesophase and could be used as a gel electrolyte in DSSCs . The major issue of the LLC gel electrolytes is that it is difficult to effectively combine the gel electrolyte and DSSC electrodes.…”

Lyotropic Liquid Crystalline Mesophases of Lithium Dihydrogen Phosphate and 10‐Lauryl Ether Stabilized with Water or Phosphoric Acid

“…This work is an important extension of LiA:C 12 E 10 : H 2 O LLC materials, where LiA is LiCl, LiBr, LiI, LiNO 3 , LiSCN, LiSO 3 CF 3 etc. [6,13,17] Note that all above LiX salts have good solubility in aqueous media. Especially, with the help of CE, the solubility limits of these salts can be further improved to accommodate an extensive amount of LiA species in the hydrophilic domains of a salt-surfactant LLC mesophase.…”

Polyfunctional Nanosystems on Amphiphilic and Hybrid Platform: Self-Assembly, Mesogenic Properties and Application

“…Было установлено, что жидкокристаллическая мезофаза чувствительна к типу аниона в применяемых солях и ионной силе среды. В настоящее время эти исследования продолжаются; металлсодержащие лиотропные ЖК успешно используются в качестве темплатов для получения мезопористых солей ванадия, лития и других элементов [108][109][110]. Применение в качестве лигандов переходных металлов находят и катионные ПАВ.…”