Journal Article transition metal dichalcogenides light-emitting devices CMOS inverters Gels Ionic Liquids Ions Organic Chemicals Polymers Research Support, Non-U.S. Gov't Review alloys chemical vapor deposition chiral electroluminescence electric double layer transistors electric double layers electroluminescence electrolyte flexible electronics heterostructure ion gels light-emitting device light-emitting diode optoelectronics p-i-n junction strain effects transition metal dichalcogenide transition metal dichalcogenide monolayers valleytronics zinc oxide