Effects of ultraviolet and heat treatment on the performance of photovoltaic cells with vinyl-based conjugated polymers

The effects of ultraviolet light and heat treatment at the condition of an inert gas environment on the performance of polymer photovoltaic cells (PVCs) with poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and its blend with [1-(3-methoxycarbonyl)-propyl-1-1-phenyl-(6,6)C61] (PCBM) are investigated. It is found that photo cross-linking between vinyl pieces in the polymer backbone is limited in a blend film even though it takes place in a pure polymer film. This makes the PVCs with the blend heterojunction structures show excellent UV and heat stability if the temperature is lower than 120 °C.