橡胶
材料科学
有机太阳能电池
接受者
无定形固体
离域电子
异质结
开路电压
化学物理
微观结构
电压
结晶学
光电子学
凝聚态物理
物理
化学
复合材料
聚合物
量子力学
作者
Guy Olivier Ngongang Ndjawa,Kenneth R. Graham,Sonya Mollinger,Di Wu,David Hanifi,Rohit Prasanna,Bradley D. Rose,Sukumar Dey,Liyang Yu,Jean‐Luc Brédas,Michael D. McGehee,Alberto Salleo,Aram Amassian
标识
DOI:10.1002/aenm.201601995
摘要
In organic solar cells (OSCs), the energy of the charge‐transfer (CT) complexes at the donor–acceptor interface, E CT , determines the maximum open‐circuit voltage ( V OC ). The coexistence of phases with different degrees of order in the donor or the acceptor, as in blends of semi‐crystalline donors and fullerenes in bulk heterojunction layers, influences the distribution of CT states and the V OC enormously. Yet, the question of how structural heterogeneities alter CT states and the V OC is seldom addressed systematically. In this work, we combine experimental measurements of vacuum‐deposited rubrene/C 60 bilayer OSCs, with varying microstructure and texture, with density functional theory calculations to determine how relative molecular orientations and extents of structural order influence E CT and V OC . We find that varying the microstructure of rubrene gives rise to CT bands with varying energies. The CT band that originates from crystalline rubrene lies up to ≈0.4 eV lower in energy compared to the one that arises from amorphous rubrene. These low‐lying CT states contribute strongly to V OC losses and result mainly from hole delocalization in aggregated rubrene. This work points to the importance of realizing interfacial structural control that prevents the formation of low E CT configurations and maximizes V OC .
科研通智能强力驱动
Strongly Powered by AbleSci AI