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Experiments show that grain boundaries (GBs) are detrimental to MAPbI3 (MA = CH3NH3+) optoelectronic properties, while passivation with alkali metals greatly improves performance. Using ab initio n...

Perovskite solar cells have attracted intense attention over the past decade because of their low cost, abundant raw materials, and rapidly growing power conversion efficiency (PCE). However, nonradiative charge carrier losses still constitute a major factor limiting the PCE to well below the Shockley-Queisser limit. This Perspective summarizes recent atomistic quantum dynamics studies on the photoinduced excited-state processes in metal halide perovskites (MHPs), including both hybrid organic-inorganic and all-inorganic MHPs and three- and two-dimensional MHPs. The simulations, performed using a combination of time-domain ab initio density functional theory and nonadiabatic molecular dynamics, allow emphasis on various intrinsic and extrinsic features, such as components, structure, dimensionality and interface engineering, control and exposure to various environmental factors, defects, surfaces, and their passivation. The detailed atomistic simulations advance our understanding of electron-vibrational dynamics in MHPs and provide valuable guidelines for enhancing the performance of perovskite solar cells.

The ordered alignment of polar organic cations in hybrid organic–inorganic perovskites causes a ferroelectric phase, which is believed to be benign for photovoltaic devices. Using a combination of ...

Experiments show that excess lead atoms accelerate charge recombination while oxygen passivation can heal the defects and enhance solar cell efficiency. Using ab initio nonadiabatic (NA) molecular ...

We report the growth and structural properties of Bi thin films on TiSe2 substrates by using a low-temperature scanning tunneling microscope. Extended Bi(110) thin films are formed on the TiSe2 sub...

Using time domain density functional theory combined with nonadiabatic (NA) molecular dynamics, we show that electron-hole recombination takes subnanoseconds in FAPbI3, showing excellent agreement with experiment. Cs doping retards charge recombination by factors of 1.1 and 3.1 due to lattice contraction and octahedral tilting, respectively. Lattice contraction decreases the NA coupling and increases the coherence time arising from the suppressed atomic fluctuations, slightly slowing recombination because the two factors have an opposite influence on quantum transition. In contrast, octahedral tilting simultaneously decreases the NA coupling, thanks to the reduced overlap between Pb and I orbitals, and the coherence time, extending the excited-state lifetime over 1 ns. Our simulations provide a mechanistic understanding for delayed charge losses in the mixed Cs and FA system, suggesting a rational strategy to improve perovskite solar cell performance.