SEARCH Articles Figures Tables Hole injection efficiency from metals transport layers Hole transport layer, HTL Hole transport layers Hole transport layers Hole transport layers, injection currents Hole transporter Hole transporting Hole-transporting layer conductivity Hole-transporting layer multilayer Hole-transporting materials blocking layers Light emitting diode hole transport layer Light hole-transporting layer Solution-Processed Metal Oxides Functioning as Hole Transport Layers (HTLs) Subject hole transport layer Use as hole transport layer