Electrodeposited PEDOT:PSS-Al(2)O(3) Improves the Steady-State Efficiency of Inverted Perovskite Solar Cells

The atomic layer deposition (ALD) of Al(2)O(3) between perovskite and the hole transporting material (HTM) PEDOT:PSS has previously been shown to improve the efficiency of perovskite solar cells. However, the costs associated with this technique make it unaffordable. In this work, the deposition of an organic–inorganic PEDOT:PSS-Cl-Al(2)O(3) bilayer is performed by a simple electrochemical technique with a final annealing step, and the performance of this material as HTM in inverted perovskite solar cells is studied. It was found that this material (PEDOT:PSS-Al(2)O(3)) improves the solar cell performance by the same mechanisms as Al(2)O(3) obtained by ALD: formation of an additional energy barrier, perovskite passivation, and increase in the open-circuit voltage (V(oc)) due to suppressed recombination. As a result, the incorporation of the electrochemical Al(2)O(3) increased the cell efficiency from 12.1% to 14.3%. Remarkably, this material led to higher steady-state power conversion efficiency, improving a recurring problem in solar cells.