Thin Solid Films, Vol.629, 11-16, 2017
Mechanism study on enhanced open-circuit voltage of perovskite solar cells with vapor-induced TiO2 as electron-transport layer
This study presents an effective method to enhance the open-circuit voltage (V-OC) of methylammoniumlead iodide (MAPbI3) perovskite solar cell. The electron transport layer (ETL) of TiO2 is prepared via a vapor-induced process at 180 degrees C, much lower than the processing temperature of TiO2 for the conventional device typically beyond 500 degrees C. Such vapor-induced method has been demonstrated to introduce hydroxyl group (OH) onto the surface of TiO2 without changing the crystal phase of the bulk TiO2, while the surface state for TiO2 film can be modified, which subsequently results in the increasement of its work function and enlarges the energy gap between TiO2 layer and Au anode. As a result, a VOC of 1.03 V for MAPbI(3) solar cell based on 180 degrees C-TiO2 is attained with an increment of 0.2 V from0.84 V for the devices with 500 degrees C-TiO2 as ETL. The maximumpower conversion efficiency is also raised by about 20% compared to the control device with 500 degrees C-TiO2 as ETL. (C) 2017 Published by Elsevier B.V.