We have demonstrated an efficiency enhancement in polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs) by introducing solution-based titanium oxide (TiO(x)) layer between the polymer and Al electrode as an electron transport/injection layer. For the PLED case, the TiOx layer reduces the barrier height between the polymer and Al cathode, thereby facilitating the electron injection and enhancing the device performance. For the PSCs case, the TiOx layer plays a role as an optical spacer in PSCs leading an increase in absorption of photon in active layer by modifying the spatial distribution of the light intensity inside the device, thereby creating more photogenerated charge carriers in the bulk heterojunction layer. (C) 2009 Elsevier B. V. All rights reserved.