Ultrafast Interfacial Charge Transfer Initiates Mechanical Stress and Heat Transport at the Au‐TiO2 Interface

• Published in: Advanced science 2024-09, Vol.11 (34), p.e2400919-n/a
• Main Authors: Heo, Jun, Segalina, Alekos, Kim, Doyeong, Ahn, Doo‐Sik, Oang, Key Young, Park, Sungjun, Kim, Hyungjun, Ihee, Hyotcherl
• Format: Article
• Language: English
• Subjects: Energy; hot carrier dynamics; Interfaces; interfacial charge transfer; interfacial coupling; Investigations; Lasers; metal‐semiconductor interface; Photovoltaic cells; Scanning electron microscopy; Spectrum analysis; ultrafast electron diffraction; ultrafast heat transfer; Wavelet transforms
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202400919

Metal‐semiconductor interfaces are crucial components of optoelectronic and electrical devices, the performance of which hinges on intricate dynamics involving charge transport and mechanical interaction at the interface. Nevertheless, structural changes upon photoexcitation and subsequent carrier transportation at the interface, which crucially impact hot carrier stability and lifetime, remain elusive. To address this long‐standing problem, they investigated the electron dynamics and resulting structural changes at the Au/TiO2 interface using ultrafast electron diffraction (UED). The analysis of the UED data reveals that interlayer electron transfer from metal to semiconductor generates a strong coupling between the two layers, offering a new way for ultrafast heat transfer through the interface and leading to a coherent structural vibration that plays a critical role in propagating mechanical stress. These findings provide insights into the relationship between electron transfer and interfacial mechanical and thermal properties. Their research investigates the dynamics of metal‐semiconductor interfaces, crucial for optoelectronic and electrical devices. Using UED, they reveal how interlayer electron transfer at the Au/TiO2 interface induces strong coupling, enabling ultrafast heat transfer and coherent structural vibrations. These insights elucidate the interplay between electron dynamics and mechanical/thermal properties at interfaces and deepens understanding of relaxation mechanisms in photogenerated hot charge carriers, with potential impact on energy conversion and catalysis.