Carrier Extraction from Perovskite to Polymeric Charge Transport Layers Probed by Ultrafast Transient Absorption Spectroscopy
| Autor: | Frédéric Laquai, Erkan Aydin, Marios Neophytou, Mingcong Wang, Esma Ugur, Jafar Iqbal Khan, Iain McCulloch, Stefaan De Wolf, Mindaugas Kirkus |
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| Rok vydání: | 2019 |
| Předmět: |
Electron mobility
Materials science 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Chemical physics Ultrafast laser spectroscopy General Materials Science Physical and Theoretical Chemistry Diffusion (business) 0210 nano-technology Spectroscopy Absorption (electromagnetic radiation) Ultrashort pulse Recombination Perovskite (structure) |
| Zdroj: | The Journal of Physical Chemistry Letters. 10:6921-6928 |
| ISSN: | 1948-7185 |
| Popis: | The efficiency of state-of-the-art perovskite solar cells is limited by carrier recombination at defects and interfaces. Thus, understanding these losses and how to reduce them is the way forward toward the Shockley-Queisser limit. Here, we demonstrate that ultrafast transient absorption spectroscopy can directly probe hole extraction and recombination dynamics at perovskite/hole transport layer (HTL) interfaces. To illustrate this, we employed PDPP-3T as HTL because its ground-state absorption is at lower energy than the perovskite's photobleach, enabling direct monitoring of interfacial hole extraction and recombination. Moreover, by fitting the carrier dynamics using a diffusion model, we determined the carrier mobility. Afterwards, by varying the perovskite thickness, we distinguished between carrier diffusion and carrier extraction at the interface. Lastly, we prepared device-like structures, TiO2/perovskite/PDPP-3T stacks, and observed reduced carrier recombination in the perovskite. From PDPP-3T carrier dynamics, we deduced that hole extraction is one order faster than recombination of holes at the interface. |
| Databáze: | OpenAIRE |
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