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HL: Fachverband Halbleiterphysik

HL 31: Poster II

HL 31.68: Poster

Dienstag, 26. Februar 2008, 16:30–19:00, Poster D

Development of Al-doped ZnO-nanocrystals for applications in advanced cell concepts of organic photovoltaics — •Daniel Rauh¹, Volker Lorrmann¹, Maria Hammer², Andreas Sperlich², Moritz Liedke¹, Carsten Deibel², Ingo Riedel¹, and Vladimir Dyakonov^1,2 — ¹Bavarian Centre for Applied Energy Research (ZAE Bayern), Functional Materials for Energy Technology, Am Hubland, D-97074 Würzburg — ²Experimental Physics VI, Physical Institute, Julius-Maximilian University of Würzburg, Am Hubland, D-97074 Würzburg

We developed Al doped ZnO-nanocrystals (nc-ZnO:Al) via wet chemical synthesis. XRD-analysis, electron spin (ESR) and electron-nuclear spin double resonance (ENDOR) confirm that nc-ZnO:Al grows in Wurtzite structure and aluminium enters the crystal on site of the Zn-atom. ESR experiments on blends of P3HT and nc-ZnO:Al confirm light-induced charge separation with resonances assigned to polarons on P3HT and electrons in the nc-ZnO:Al domain. Photoinduced absorption spectroscopy was applied to rationalize infiltration of P3HT into porous nc-ZnO:Al matrix: Spectra of bilayer structures reveal coexistence of positive polarons and triplet excitons while strong polaron formation is accompanied with complete quenching of triplet excitons (TE) for infiltrated ZnO:Al-matrices. Polaron formation and quenching of TE is ascribed to the enlarged interface in the bulk heterojunction. ENDOR-measurements as well as photoluminescence studies on pure ZnO:Al confirm that sodium, incorporated during synthesis, result in deep-level acceptor states in the middle of the band gap.