Organic solar cell optimizations in both space and energy regimes: large open circuit voltage from a -DBAB- type block copolymer

Abstract

Organic/polymeric solar cells can be optimized in both space (morphology) and energy regimes to minimize the 'photon loss', the 'exciton loss' and the 'carrier loss'. In spatial regime optimization, for instance, a set of thin film solar cell devices fabricated from a -donor-bridgeacceptor-bridge-(-DBAB-) type block copolymer containing polyphenylenevinylene (PPV) conjugated donor and acceptor segments exhibited open circuit voltages (V oc ) up to 1.1 volt, which is very impressive for organic/polymeric photovoltaics, though the photoelectric quantum and power conversion efficiencies are still very low due to energy gap mismatch and very small and not yet optimized short circuit current (in micro Amps regime).

Conjugated polymers with tethered electron‐accepting moieties as ambipolar materials for photovoltaics

“…The preparation of double‐cable copolymers , so far dictated mainly by problems encountered during synthesis and by the need of solubility, can now be actively regarded as a valuable strategy. An extreme of this approach are D–A diblock copolymers, as suggested by different groups 24, 87, 88. Moreover, the need for a very high fullerene content (as much as 75–80 wt%) typical of the first efficient BHSCs32 has also been meantime re‐evaluated: to date the most efficient BHSCs have a fullerene loading of about 44 wt% 5, 6…”