Strich Robert, Faraji Shirin, Palacino-González Elisa
Institute of Theoretical and Computational Chemistry, Heinrich-Heine Universität Düsseldorf, Germany.
Phys Chem Chem Phys. 2025 Sep 10;27(35):18525-18538. doi: 10.1039/d5cp01684c.
Quantum coherences play a central role in a broad range of fields, including functional energy materials, biological systems, and molecular quantum information science. Coherences encode critical information about the phase and dynamics of a system, and their interaction with its environment. Particularly, the ultrafast charge transfer process between electron donor and acceptor species in functional energy materials is influenced by vibronic coherences. A key limitation arises from the dephasing of coherences due to dissipation, causing loss of information and limiting applications of molecular systems. Extending and controlling coherence lifetimes would enable the rational design of smarter materials with optimised properties. Here we introduce a novel idea using chirped excitations as a pathway to extend quantum coherence lifetimes, enhancing their robustness against dissipation. A detailed analysis of the light-induced molecular quantum dynamics and wave packet evolution from first-principles models constructed at the donor-acceptor heterojunction of an organic photovoltaic blend is discussed. We demonstrate that tuning the chirp of the excitation pulse, vibronic coherence lifetimes can be extended up to the picosecond timescale. Chirped excitations also enable tunable spatial localisation of the induced wave packet, with localisation controlled by the chirp intensity. These effects are observed consistently across different donor-acceptor adducts selected from the molecular dynamics structure of the blend. Our results introduce a new degree of freedom for coherent control in molecular systems, offering a promising pathway toward the development of advanced functional energy materials and applications in molecular quantum information science.
量子相干在广泛的领域中起着核心作用，包括功能能源材料、生物系统和分子量子信息科学。相干性编码了有关系统的相位和动力学及其与环境相互作用的关键信息。特别是，功能能源材料中电子供体和受体物种之间的超快电荷转移过程受振动相干性的影响。一个关键限制源于由于耗散导致的相干性退相，这会导致信息丢失并限制分子系统的应用。延长和控制相干寿命将能够合理设计具有优化性能的更智能材料。在这里，我们引入了一个新颖的想法，即使用啁啾激发作为延长量子相干寿命的途径，增强其对耗散的鲁棒性。讨论了从有机光伏共混物的供体-受体异质结构建的第一性原理模型对光诱导分子量子动力学和波包演化的详细分析。我们证明，通过调整激发脉冲的啁啾，可以将振动相干寿命延长到皮秒时间尺度。啁啾激发还能使诱导波包实现可调谐的空间定位，定位由啁啾强度控制。在从共混物的分子动力学结构中选择的不同供体-受体加合物中均一致观察到了这些效应。我们的结果为分子系统中的相干控制引入了一个新的自由度，为先进功能能源材料的开发以及分子量子信息科学中的应用提供了一条有前景的途径。
