摘要:

Poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) is one of the most widely used hole transport layers (HTL) in inverted perovskite solar cells (PSCs) due to its simple solution-processed ability, high transparency, and conductivity. However, PEDOT: PSS-based devices suffer a lower open-circuit voltage (V-oc) than devices with the conventional structure. To address this issue, we fabricated ammonia-modified PEDOT: PSS films by simply doping PEDOT: PSS solution with different ratio of ammonia. The acidity of PEDOT: PSS can be neutralized by the doped ammonia, which inhibits the ion-exchange reaction between PSS-H and CH3NH3I, thus retarding the reduction of the work function for PEDOT: PSS to some extent. As a result, a superior power conversion efficiency (PCE) of 15.5% was obtained for the device based on the ammonia-doped PEDOT: PSS HTL than that of the pristine PEDOT: PSS-based device. We ascribe the PCE enhancement to the increased Voc and fill factor (FF), which is attributed not only to the better energy-level alignment between the ammonia-modified PEDOT: PSS film and perovskite layer but also to the increased grain size and crystallinity of perovskite film. (C) 2017 Published by Elsevier B.V.