AVS 66th International Symposium & Exhibition
    Nanometer-scale Science and Technology Division Thursday Sessions
       Session NS-ThP

Paper NS-ThP4
A Nanoscopic View of Photo-induced Charge Transfer in Organic Nano-crystalline Heterojunctions

Thursday, October 24, 2019, 6:30 pm, Room Union Station B

Session: Nanometer-scale Science and Technology Poster Session
Presenter: Qian Zhang, Weizmann Institute of Science, Israel
Authors: Q. Zhang, Weizmann Institute of Science, Israel
S.R. Cohen, Weizmann Institute of Science, Israel
B. Rybtchinski, Weizmann Institute of Science, Israel
Correspondent: Click to Email
Organic photovoltaics are promising as cost-efficient, tunable, and flexible platforms for solar energy conversion, yet their performance and stability are still far from optimal. Here we present a study of photo-induced charge transfer processes between electron donor and acceptor organic nanocrystals, as part of our path-finding effort to develop robust and efficient organic nanocrystalline materials for photovoltaic applications. We produced sub-micron to microns-long nanocrystals of perylenediimides (PDIs) as electron acceptors, and with Copper Phthalocyanine (CuPc) as the electron donor. Three different configurations of donor-acceptor heterojunctions were prepared. Charge transfer in the heterojunctions was studied with Kelvin-probe force microscopy (KPFM) under laser or white light excitation. We also conducted theoretical calculations and time-resolved photo-luminescence measurements to understand the differences in the photovoltaic processes of these organic nanocrystals. Our work demonstrates that excitonic properties can be tuned by controlling the crystal and interface structures in the nanocrystalline heterojunctions, in order to minimize photo-voltaic losses.