Wei Xiong

Theoretical results demonstrate that interfacial molecular conformations directly influence charge separation dynamics in polymer blend solar cells. Experimentally, it would be very beneficial to be able to monitor the interaction between interfacial conformations and dynamics. However, since charge separation mostly happens at disordered hidden interfaces in thick samples, it is very challenging to capture such processes using existing spectroscopic techniques. We will develop ultrafast surface sensitive spectroscopy to follow both the charge separation dynamics and interfacial conformation simultaneously.

Nanoparticles are the fundamental building blocks for complex nano architectures. It is helpful to design nano-devices bottom-up when the electronic structures of individual components, such as nanopartilces, are well characterized. It is challenging to investigate the electronic structure without external perturbation, since the nanoparticles are typically suspended in solution phase environment. We combined aerosol techniques and a classic electronic structure instrument - Velocity Map Imaging spectroscopy together to investigate nanoparticles suspended in the vacuum. Using this novel apparatus, nanoparticle electronic structure and dynamics with no external perturbation can be unambiguously extracted from the photoelectron signal.