Spray coated europium doped PEDOT:PSS anode buffer layer for organic solar cell: The role of electric field during deposition

Poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) doped with Eu3+ is spray deposited for creating an Anode buffer layer (ABL). The doping of Eu3+ in PEDOT:PSS causes the down-shifting of the UV light to visible spectrum enhancing the photon concentration in this region. The use of electric field during the spray deposition of undoped and Eu3+ doped PEDOT:PSS film improved the surface morphology and the electrical conductivity, which help to improve the solar cell performance. The organic solar cell (ITO/ABL/PTB7:PC71BM/Al) fabricated using the electric field assisted spray deposited Eu3+ doped PEDOT:PSS ABL is shown improvement in the power conversion efficiency in comparison to the device fabricated using undoped PEDOT:PSS without electric field. This enhancement in the efficiency of the device in terms of current density and Fill factor can be attributed to an increase in the photon concentration in visible region due to the downshifting and improvement in the surface morphology and conductivity due to applied electric field during deposition.