Orientation dependant charge transfer at fullerene/Zn-phthalocyanine (C60/ZnPc) interface: Implications for energy level alignment and photovoltaic properties

Journal Article · Mon Aug 01 00:00:00 EDT 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4960637· OSTI ID:22594321

Javaid, Saqib ^[1]

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1. EMMG, Physics Division, PINSTECH, P.O. Nilore, Islamabad 45650 (Pakistan)

Recently, experimental results have shown that photovoltaic properties of Fullerene (C60)/Phthalocyanine based devices improve considerably as molecular orientation is changed from edge-on to face-on. In this work, we have studied the impact of molecular orientation on C60/ZnPc interfacial properties, particularly focusing on experimentally observed face-on and edge-on configuration, using density functional theory based simulations. The results show that the interfacial electronic properties are strongly anisotropic: direction of charge transfer and interface dipole fluctuates as molecular orientation is switched. As a result of orientation dependant interface dipole, difference between acceptor LUMO and donor HOMO increases as the orientation is changed from edge-on to face-on, suggesting a consequent increase in open circuit voltage (V{sub OC}). Moreover, adsorption and electronic properties indicate that the interfacial interactions are much stronger in the face-on configuration which should further facilitate the charge-separation process. These findings elucidate the energy level alignment at C60/ZnPc interface and help to identify interface dipole as the origin of the orientation dependence of V{sub OC}.

• OSTI ID: 22594321
• Journal Information: Applied Physics Letters, Vol. 109, Issue 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ADSORPTION
ALIGNMENT
ANISOTROPY
COMPUTERIZED SIMULATION
CONFIGURATION
DENSITY FUNCTIONAL METHOD
DIPOLES
ELECTRIC POTENTIAL
FULLERENES
INTERFACES
PHOTOVOLTAIC EFFECT
PHTHALOCYANINES
SEPARATION PROCESSES
SWITCHES