▎ 摘　　要

NOVELTY - Producing functional graphene solution comprises (a) oxidizing graphite to produce oxidized graphene solution, (b) performing spray drying the oxidized graphene solution, and (c) reacting the dried oxidized graphene powder with organic compound. USE - The functional graphene solution is useful in hole transport layer of organic light emitting diode and organic solar cell (all claimed). ADVANTAGE - The method is simple and economical, and produces functional graphene solution in mass. The functional graphene solution has excellent dispersion stability, improves durability and stability of the organic light emitting diode, prevents moisture and oxygen penetration in device, forms coating layer which is serving as buffer layer for easily transferring holes generated in the photoactive layer toward the anode, can smoothly flow holes in the organic solar cell, and improves efficiency of organic solar cell. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) organic light emitting diode comprising a cathode, an anode, a hole transport layer, an electron transport layer and a light emitting layer, where the hole transport layer is formed with a coating layer coated with the functional graphene solution; and (2) organic solar cell comprising a first electrode, a second electrode facing the first electrode, a photoactive layer disposed between the first electrode and the second electrode, and a hole transport layer, where the hole transport layer is formed with a coating layer coated with the functional graphene solution.