Regensburg 2019 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: Focus: Controlling Phase Formation Dynamics in Solution Processed Semiconductors - organized by Christoph Brabec, Jens Harting and Hans-Joachim Egelhaaf

CPP 39.6: Talk

Wednesday, April 3, 2019, 16:45–17:00, H14

Inner structure analysis of quantum dot solids for photo-devices — •Wei Chen and Peter Müller-Buschbaum — TU München, Physik-Department, LS Funktionelle Materialien, James-Franck-Str. 1, 85748 Garching, Germany

Quantum dots (QDs) with near infrared emission are promising in both photodetectors (PDs) for sensing and photovoltaics (PVs) for solar energy conversion. High quality QDs are normally synthesized in solution and capped with organic ligands. To efficiently functionalize the QDs' array for PD or PV devices, the ligand exchange treatments, in solution or on solids, to colloidal QDs are necessary by exchanging or removing the long chain organic ligands. These treatments will not only decrease the inter-dot spacing between neighboring QDs to improve their electro-coupling behavior, which is beneficial for the energy transfer, but also change the stacking behavior of QD particles in solid from colloidal state to close packed state. This structure transition is now investigated by grazing incidence X-ray scattering and it is found that QDs prefer to stack in a face-centered cubic when they are in superlattice structure (colloidal state) by spin-coating. The stacking structure will change to a body-centered cubic style in a close packed solid after ligand exchange. Thus, the inner morphologies of QDs' close packed solids by different treatments are well studied. The optimized devices demonstrate a better device performances.