Study of Structure and Electronic Properties of Heterointerfaces for Photovoltaic Applications

Abstract

The linkage between the atomic structure and the electronic property is complex for heterointerfaces involving multicomponent organic−inorganic systems because of large configurations and chemical possibilities. Understanding the structure−property relationship at the interface becomes further complicated with an asymmetric structure of organic molecules compared to the interface between planer solids. Here, we report on ab inito molecular dynamics (AIMD) simulations of the perovskite/PCBM ([6,6]-phenyl-C 61 -butyric acid methyl ester) interface, where PCBM is an asymmetric molecule. Our AIMD calculations help us to navigate the vast number of possible atomic configurations of the interface. We have found that PCBM prefers to bind with the perovskite surface via an ester moiety over its fullerene moiety. The bonding at the interface and its stability are sensitive to the chemical composition at the perovskite surface, the PbI 2 -terminated surface making a stronger binding ≈1 eV with PCBM, compared to the MAI-terminated surface. Later, we systematically studied the role of atomic defects on the perovskite surface and interface and linked it to interface stability and electronic properties.

Small practical cluster models for perovskites based on the similarity criterion of central location environment and their applications

“…The periodic calculations of perovskites have had some success in predicting the structure and relative properties of photoelectric conversion. [16][17][18][19] However, the bulk phase calculations are time-consuming 20 and the periodic model does not flexibly reflect the local information. The internal structure and the interactions between the organic cation and inorganic BX framework remain to be studied.…”

Quantum chemical investigation of the effect of alkali metal ions on the dynamic structure of water in aqueous solutions

“…Unfortunately, they are computationally rather expensive, 29 making it difficult to obtain trajectories of sufficient simulation time length for relevant model system sizes and complexity. 30 In this work, we instead employ the density-functional tightbinding (DFTB) method, [31][32][33] which is an approximation to traditional DFT that is 100 to 1000 times faster and provides a trade-off between accuracy and computational efficiency. 34 Since DFTB is a quantum chemical method and able to compute nuclear forces during MD simulations by solving Kohn-Sham equations on-the-y, DFTB/MD 35 trajectories not only provide structural features but also contain information on the electronic structure such as charge distributions.…”