Hot Carrier Cooling and Recombination Dynamics of Chlorine-Doped Hybrid Perovskite Single Crystals

Optimizing Excited Charge Dynamics in Layered Halide Perovskites through Compositional Engineering

Dion-Jacobson phase multilayered halide perovskites (MLHPs) improve carrier transport and optoelectronic performance thanks to their shorter interlayer distance, long carrier lifetimes, and minimized nonradiative losses. However, limited atomistic insights into dynamic structure-property relationships hinder rational design efforts to further boost their performance. Here, we employ nonadiabatic molecular dynamics, time-domain density functional theory, and unsupervised machine learning to uncover the impact of A-cation mixing on controlling the excited carrier dynamics and recombination processes in MLHPs. Mixing smaller-sized Cs with methylammonium in MLHP weakens electron-phonon interactions, suppresses the nonradiative losses, and slows down intraband hot electron relaxations. On the contrary, larger-sized guanidinium incorporation accelerates nonradiative relaxations. The mutual information analyses reveal the importance of interlayer distances, intra- and interoctahedral angle dynamics, and A-cation motion in extending the excited carrier lifetime by mitigating nonradiative losses in MLHPs. Our work provides a guideline for strategically choosing A-cations to boost the optoelectronic performance of layered halide perovskites.

Enhanced Higher Harmonic Generation in Modified MAPbBr3-xClx Single Crystal by Additive Engineering

Mixed-halide perovskite materials (MHSCs) hold significant interest in photonics applications owing to their inherent advantages, including tunable bandgap properties, remarkable defect tolerance characteristics, and facile processability. These attributes position MHSCs as up-and-coming materials for various applications. However, the commercialization of these materials is severely affected by external factors, such as humidity and oxygen. The current work studies change in higher harmonics generation (HHG) in MAPbBr3-xClx single crystals (MHSC) with changing nitrogen-based additives. These additives act as a passivating layer and improve the nanolevel crystallinity. The additive engineering strategy impacts morphological and optical properties, depending on the additive's interaction.

Chemically Engineered Avenues: Opportunities for Attaining Desired Carrier Cooling in Perovskites

Hot carrier extraction-based devices are presently being persuaded as the most revolutionary means of surpassing the theoretical thermodynamic conversion efficiency limit (∼67 % for a model hot carrier solar cell). However, for practical realisation, there stand various hurdles that need to be surmounted, a major among all being the rapid hot carrier cooling rate. Though, the perovskite family has already demonstrated itself to exhibit slower cooling in contrast to the prototypical semiconductors. Decelerating this entire process of cooling further can prove to be a crucial stride in this regard. Quite contrarily, for the optoelectronic applications the situation is entirely conflicting where quick rate of cooling is a chief prerequisite. In the recent times, there have been various key developments that have targeted altering this cooling rate by various chemically engineered strategies. This review highlights such blueprints that can be utilized towards the advantageous alteration of the carrier cooling in accordance with the device requirements.