Phonon-Assisted Ultrafast Charge Separation in a Realistic PCBM Aggregate

Abstract

Organic solar cells must separate strongly bound electron-hole pairs into free charges. This is achieved at interfaces between electron donor and acceptor organic semiconductors. The most popular electron acceptor is the fullerene derivative PCBM. Electron-hole separation has been observed on femtosecond timescales, which is incompatible with conventional Marcus theories of organic transport. In this work we show that ultrafast charge transport in PCBM arises from its broad range of electronic eigenstates, provided by the presence of three closely spaced delocalised bands near the LUMO level. Vibrational fluctuations enable rapid transitions between these bands, which drives an electron transport of $\sim$3 nm within 100 fs. All this is demonstrated within a realistic tight binding Hamiltonian containing transfer integrals no larger than 8 meV.

arXiv comment6 pages, 3 figures

References in corpus (7)

• Environment-Assisted Quantum Walks in Photosynthetic Energy Transfer
• The Role of Driving Energy and Delocalised States for Charge Separation in Organic Semiconductors
• Dephasing assisted transport: Quantum networks and biomolecules
• Efficient simulation of strong system-environment interactions
• A general approach to quantum dynamics using a variational master equation: Application to phonon-damped Rabi rotations in quantum dots
• Noise-induced quantum coherence drives photocarrier generation dynamics at polymeric semiconductor heterojunctions
• Impact of quantized vibrations on the efficiency of interfacial charge separation in photovoltaic devices

Cited by in corpus (11)

• Engineering vibrationally-assisted energy transfer in a trapped-ion quantum simulator
• Even a little delocalization produces large kinetic enhancements of charge-separation efficiency in organic photovoltaics
• Ultrafast dynamics of photoinduced charge separation
• Delocalisation enables efficient charge generation in organic photovoltaics, even with little to no energetic offset
• Origin of space-separated charges in photoexcited organic heterojunctions on ultrafast time scales
• Coherent quantum dynamics launched by incoherent relaxation in a quantum circuit simulator of a light-harvesting complex
• Analysis of the non-Markovianity for electron transfer reactions in an oligothiophene-fullerene heterojunction
• Exciton Dissociation and Charge Separation at Donor-Acceptor Interfaces from Quantum-Classical Dynamics Simulations
• Polaronic quantum diffusion in dynamic localization regime
• Identification of Ultrafast Photophysical Pathways in Photoexcited Organic Heterojunctions
• Superintermolecular orbitals in the C${}_{60}$/pentacene complex