Origin of fullerene-induced vitrification of fullerene: donor polymer photovoltaic blends and its impact on solar cell performance - Westacott, P; Treat, ND; Martin, J; Bannock, JH; de, Mello JC; Chabinyc, M; Sieval, AB; Michels, JJ; Stingelin, N (Journal of Materials Chemistry A, 2016)