Nonadiabatic charge dynamics in novel solar cell materials

Abstract

The review describes recent research into the nonequilibrium phenomena in nanoscale materials, with focus on charge separation and recombination, that form the basis for photovoltaic and photocatalytic devices. Nonadiabatic molecular dynamics combined with ab initio real-time time-dependent density functional theory enable us to model time-resolved laser experiments at the atomistic level, emphasizing realistic aspects of the materials, such as defects, dopants, boundaries, chemical bonding, etc. A variety of systems have been considered, including bulk semiconductors sensitized by semiconducting/metallic nanoparticles and graphene, nanocrystal/molecule junctions, polymer interfaces with carbon nanotubes and nanoclusters, van der Waals heterojunctions, black phosphorus, and hybrid organic-inorganic perovskites. The detailed atomistic knowledge obtained from the explicit time-domain modeling generates comprehensive understanding of electron-vibrational dynamics in complex multicomponent systems, provides critical insights into quantum mechanical transport of energy and charge, and leads to valuable guidelines for improvement of solarto-electric power conversion in photovoltaic and photocatalytic applications and for efficient performance of transport devices. FIGURE 14 | Decay of populations of the first excited state in bilayer black phosphorus (BP) and at the BP/MoS 2 interface. BP/MoS 2 shows slower decay because of electron-hole separation across the interface.

Strong Influence of Decoherence Corrections and Momentum Rescaling in Surface Hopping Dynamics of Transition Metal Complexes

“…The EDC method [Eq. (6)] depends on the overall kinetic energy E kin of the system. Adding noninteracting atoms to the system will increase the overall kinetic energy and thus reduce the decoherence time.…”

Surface hopping methods for nonadiabatic dynamics in extended systems

“…This treatment is different from the Monte‐Carlo scheme discussed above, where the hopping probabilities are unchanged and frustrated surface hops can still be considered. CPA has a significantly high‐numerical efficiency, and thus has been widely utilized to study different charge and exciton dynamics in many realistic nanomaterials, especially inorganic systems . CPA has been implemented in PYXAID and Hefei‐NAMD programs.…”

Identification of Important Normal Modes in Nonadiabatic Dynamics Simulations by Coherence, Correlation, and Frequency Analyses

“…Nonadiabatic dynamics simulations are nowadays an important pillar of computational chemistry, as it allows detailed investigations of many different photophysical and photochemical processes with a wide variety of applications. [1][2][3][4][5][6] The general goal of these simulations is to describe the simultaneous evolution of electronic and nuclear degrees of freedom in a molecular system after photoexcitation. This is a very challenging task, requiring a combination of reliable electronic structure theory and suitable nuclear dynamics techniques.…”

“…21,22 [Re(CO) 3 (Im)(Phen)] + is a member of the class of Re(I) carbonyl diimine complexes that have gained large interest as bio-compatible photosensitizer for studies of electron transfer in proteins. [23][24][25] The complex' nonadiabatic dynamics was experimentally thoroughly characterized, [26][27][28] proposing that the first step after UV excitation is ultrafast intersystem crossing (ISC) from an initially excited singlet metal-to-ligand charge transfer ( 1 MLCT) state to a (triplet) 3 MLCT state, with minor involvement of a triplet intraligand ( 3 IL) state. For the same complex, in the last years a series of quantum dynamics simulations was published, [29][30][31] using MCTDH with linear vibronic coupling (LVC) models 29 with up to fifteen harmonic normal modes.…”