All polymer photovoltaics: From small inverted devices to large roll-to-roll coated and printed solar cells

Inverted all polymer solar cells based on a blend of a perylene diimide based polymer acceptor and a dithienosilole based polymer donor were fabricated from small area devices to roll-to-roll (R2R) coated and printed large area modules. The device performance was successfully optimized by using solvent additive to tune the phase separation. By adding 2% chloronaphthalene as solvent additive for small area (0.25 cm2) devices, a power conversion efficiency (PCE) up to 0.63% was achieved for inverted geometry, higher than that (0.39%) of conventional geometry. This polymer blend showed excellent solution processibility and R2R coated and printed large area (4.2 cm2) solar cells exhibited a PCE of 0.20%.