Tailoring Ordered Mesoporous Titania Films via Introducing Germanium Nanocrystals for Enhanced Electron Transfer Photoanodes for Photovoltaic Applications

• Published in: Advanced functional materials Vol. 31; no. 34
• Main Authors: Li, Nian, Guo, Renjun, Chen, Wei, Körstgens, Volker, Heger, Julian E., Liang, Suzhe, Brett, Calvin J., Hossain, Md Asjad, Zheng, Jianshu, Deimel, Peter S., Buyruk, Ali, Allegretti, Francesco, Schwartzkopf, Matthias, Veinot, Jonathan G. C., Schmitz, Guido, Barth, Johannes V., Ameri, Tayebeh, Roth, Stephan V., Müller‐Buschbaum, Peter
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01-08-2021
• Subjects: Annealing; Argon; Chemical composition; Chemical compositions; Chemical synthesis; Circuits; Copolymers; Current carriers; Electron microscopy; Electron transfer; Electron transitions; Electron transport properties; enhanced electron transfer; Germanium; Germanium compounds; germanium nanocrystals; Germanium oxides; Grazing incidence small-angle X-ray scattering; High resolution transmission electron microscopy; Materials science; Mesoporous titania; Microscopy; Morphology; Nanocomposite films; Nanocomposites; Nanocrystals; Optical properties; Ordered mesoporous; ordered mesoporous nanostructures; Perovskite; Perovskite solar cells; Perovskites; Photoanodes; Photocurrents; Photoelectric effect; Photoelectric emission; Photoelectrons; Photovoltaic applications; Photovoltaic cells; Scanning electron microscopy; Short-circuit photocurrent densities; Sol-gel processes; Solar cells; Sols; Spectrum analysis; TiO2 nanoparticles; titania; Titanium dioxide; Visible spectroscopy; X ray photoelectron spectroscopy; X ray scattering
• DOI: 10.1002/adfm.202102105
• EISSN: 1616-3028
• ISSN: 1616-301X; 1616-3028

Based on a diblock‐copolymer templated sol–gel synthesis, germanium nanocrystals (GeNCs) are introduced to tailor mesoporous titania (TiO2) films for obtaining more efficient anodes for photovoltaic applications. After thermal annealing in air, the hybrid films with different GeNC content are investigated and compared with films undergoing an argon atmosphere annealing. The surface and inner morphologies of the TiO2/GeOx nanocomposite films are probed via scanning electron microscopy and grazing‐incidence small‐angle X‐ray scattering. The crystal phase, chemical composition, and optical properties of the nanocomposite films are examined with transmission electron microscopy, X‐ray photoelectron spectroscopy, and ultraviolet–visible spectroscopy. Special focus is set on the air‐annealed nanocomposite films since they hold greater promise for photovoltaics. Specifically, the charge–carrier dynamics of these air‐annealed nanocomposite films are studied, and it is found that, compared with pristine TiO2 photoanodes, the GeNC addition enhances the electron transfer, yielding an increase in the short‐circuit photocurrent density of exemplary perovskite solar cells and thus, an enhanced device efficiency as well as a significantly reduced hysteresis.
Germanium nanocrystals (GeNCs) are introduced into a diblock‐copolymer‐templating sol–gel synthesis to fabricate ordered mesoporous TiO2/GeOx nanocomposite films for use as efficient photoanodes. The GeNC addition enhances the electron transfer, yielding an increase in short‐circuit photocurrent density and thereby an enhanced device efficiency.