Improved solar cell performance by adding ultra-thin Alq3 at the cathode interface

We report a new finding that ultra-thin Tris(8-hydroxyquinoline) aluminum (Alq(3)) improves an Al cathode interface for photovoltaic (PV) with inorganic amorphous silicon (a-Si) as well as organic bulk heterojunction (BHJ) photoactive layers. Contact resistance characterization is used to investigate the effect of the added Alq(3). The experimental results show that the inserted Alq3 is observed to reduce the contact resistance at the cathode interface. Supported by our numerical analysis, the enhanced cathode interface by Alq(3) provides better Ohmic contact, thereby increasing V-oc. The overall power efficiency is enhanced accordingly benefited by the Alq(3) added cathode regardless of photoactive layers. (C) 2014 Elsevier B.V. All rights reserved.