Understanding the mechanism and exploring the optimization strategies for organic solar cells

Both structure-property relationship and device innovation methods are studied to achieve high performance polymer solar cells. The dipole and dispersity changes of polymers play important roles in determining high solar cell performance due to different internal polarization strength with dipole changes and existence of homo coupling defects in high dispersity samples. Cooperative plasmonic effect is demonstrated to be an effective strategy to improve light absorption in the absorption region of binary solar cell devices and the absorption range could be further extended with ternary blend solar cells. Power conversion efficiencies have reached >8% in plasmonic devices and >9% in ternary blend devices. Integrating carbon nanotubes into active layer could largely increase charge separation and transport efficiencies and interfacial energy level alignment is also shown to be crucial for effective charge transport and formation of Ohmic contact at the interface.