Enhanced Performance of PTB7:PC71BM Based Organic Solar Cells by Incorporating a Nano-Layered Electron Transport of Titanium Oxide

The performance improvement of PTB7:PC71BM based organic solar cells was achieved and optimized by using a very thin layer of TiO as electron transporting layer (ETL) between the cathode electrode (Al) and active layer of the devices. Different thicknesses of TiO ETL were thermally deposited onto the solution-processed active layers followed by aluminium deposition and device encapsulation under glovebox. Results showed that with the use of 5 nm TiO the power conversion efficiency was improved from 5.6% to 9.63%. This interesting enhancement was attributed to various effects of TiO ETL at the boundary/interface of the semiconductor-metal component. Furthermore, high photosensitivity and fast photo-response for the investigated devices with the presence of TiO indicated their viable use as light photodetector.