Influence of Alq3/Au cathode on stability and efficiency of a layered organic solar cell in air

A relatively long lifetime organic solar cell, containing a thin tris-8-hydroxy-quinotato aluminum (Alq(3)) layer under an Au cathode, is described. Half-lifetime of the cell in the darkness is over 7 weeks and 30% of the initial power conversion efficiency (eta) is obtained after 18 weeks. This represents a substantial increase in lifetime compared to that of the unencapsulated Al-cathode cells. Efficiency is enhanced by 60 times compared to a cell that does not contain Alq3, being 0.60%. The proposed role of Alq(3)/Au cathode in this cell is discussed in detail. (C) 2008 Elsevier B.V. All rights reserved.