Modeling Photovoltaic Performances of BTBPD-PC61BM System via Density Functional Theory Calculations

摘要

Designing and fabricating high-performance photovoltaic devices have remained a major challenge in organic solar cell technologies.In this work,the photovoltaic performances of BTBPD-PC61BM system were theoretically investigated by means of density functional theory calculations coupled with the Marcus charge transfer model in order to seek novel photovoltaic systems.Moreover,the hole-transfer properties of BTBPD thin-film were also studied by an amorphous cell with 100 BTBPD molecules.Results revealed that the BTBPD-PC61BM system possessed a middle-sized open-circuit voltage of 0.70 V,large short-circuit current density of 16.874 mA/cm2,large fill factor of 0.846,and high power conversion efficiency of 10％.With the Marcus model,the charge-dissociation rate constant was predicted to be as fast as 3.079×1013 s-1 in the BTBPD-PC61BM interface,which was as 3-5 orders of magnitude large as the decay (radiative and non-radiative) rate constant.(108-1010 s-1),indicating very high charge-dissociation efficiency (～100％) in the BTBPD-PC61BM system.Furthermore,by the molecular dynamics simulation,the hole mobility for BTBPD thin-film was predicted to be as high as 3.970× 10-3 cm2V-1s-1,which can be attributed to its tight packing in solid state.