Production of large-area polymer solar cells by industrial silk screen printing, lifetime considerations and lamination with polyethyleneterephthalate

The possibility of making large area (100 cm(2)) polymer solar cells based on the conjugated polymer poly 1,4-(2-methoxy-5-ethylhexyloxy)phenylenevinylene (MEH-PPV) was demonstrated. Devices were prepared by etching an electrode pattern on ITO covered polyethyleneterephthalate (PET) substrates. A pattern of conducting silver epoxy allowing for electrical contacts to the device was silk screen printed and hardened. Subsequently a pattern of MEH-PPV was silk screen printed in registry with the ITO electrode pattern on top of the substrate. Final evaporation of an aluminum electrode or sublimation of a Buckminsterfullerene (C-60) layer followed by an aluminum electrode completed the device. The typical efficiency of the prototype devices consisting of three solar cells in series were 0.0046% (under AM1.5 conditions) with open-circuit voltages (V-oc) of 0.73 V and short-circuit currents (I-sc) of 20 muA cm(-2). The half-life based on I-sc in air for the devices were 63 h. The cells were laminated in a 125 mum PET encasement. Lamination had a negative effect on the lifetime. We demonstrate the feasibility of industrial production of large area solar cells (1 m(2)) by silk screen printing and envisage the possibility of production volumes 10000 m(2) h(-1) at a cost that is on the order of 100 times lower than that of the established monocrystalline silicon solar cells in terms of materials cost. (C) 2004 Elsevier B.V. All rights reserved.