Charge-transporting thin-films composed of organic compounds are used as the emissive layer or charge injection layer in organic electroluminescence (organic EL) devices. Processes for forming such thin-films are broadly divided into dry processes such as vapor deposition and wet processes such as spin coating. In comparing dry processes and wet processes, wet processes are capable of efficiently producing thin-films having a high flatness over a large surface area. Therefore, in the organic EL field where thin-films of larger surface area are desired, organic thin-films are often formed by wet processes.
In recent years, there has been a steadily growing desire for higher functionality, greater multifunctionality, smaller size, etc. in manufactured products within the organic EL field. Under such circumstances, to achieve, for example, lighter weights and thinner dimensions, substrates composed of organic compounds have come to be used in place of glass substrates, and so the treatment temperatures that can be used in manufacturing processes have become lower than in the past. As a result, there exists today in the organic EL field an increasing desire for varnishes which can be baked at lower temperatures and which, moreover, even in such cases, provide thin-films endowed with good charge transportability.