| AVS 55th International Symposium & Exhibition | |
| Energy Science and Technology Focus Topic | Thursday Sessions |
| Session EN+EM+NS+P+A+T+V-ThM |
| Session: | Energy: Tools and Approaches |
| Presenter: | A.T. Wroble, University of Illinois at Chicago |
| Authors: | A.T. Wroble, University of Illinois at Chicago D.J. Asunskis, University of Illinois at Chicago A.M. Zachary, University of Illinois at Chicago I.L. Bolotin, University of Illinois at Chicago D.J. Wallace, University of Wisonsin-Madison M. Severson, University of Wisonsin-Madison L. Hanley, University of Illinois at Chicago |
| Correspondent: | Click to Email |
Lead sulfide (PbS) nanocrystals have shown potential for use in optoelectronic applications including photovoltaics. PbS nanocrystals are grown directly into polymers or organic oligomer matrices to control the size and surface chemistry of the resulting nanocrystals. Transmission electron microscopy is used to determine the size distribution of PbS nanocrystals in organic films grown by either colloidal synthesis in polymer solutions or gaseous deposition using a cluster beam deposition source. Both the colloidal and cluster beam deposition methods are described in detail. Various techniques in photoemission spectroscopy are then applied to these PbS nanocrystal-organic films. X-ray photoelectron spectroscopy (XPS) confirms that PbS nanocrystals are present. Soft-XPS using 200 eV photon energies available at a synchrotron radiation source provides surface sensitivity to observe the interaction of the PbS nanocrystal surface with the organic matrix and is compared to XPS results obtained using 1487 eV photon energy. Little or no bonding between the PbS nanocrystals and the organic phase is observed. The core of the nanocrystals are found to be 1:1 Pb:S, but their surfaces are enriched in Pb. Finally, core level binding energy shifts in XPS under simulated solar irradiation are used for contact-free evaluation of element-specific photovoltaic electrical response of these PbS nanocrystal-organic thin films.