Charge Carrier Dynamics upon Sub-bandgap Excitation in Methylammonium Lead Iodide Thin Films: Effects of Urbach Tail, Deep Defects, and Two-Photon Absorption
| Autor: | Caselli, Valentina M., Wei, Zimu, Ackermans, Marnix M., Hutter, Eline M., Ehrler, Bruno, Savenije, Tom J., Sub ARC Chemical Building Blocks Cons., Inorganic Chemistry and Catalysis |
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| Přispěvatelé: | Sub ARC Chemical Building Blocks Cons., Inorganic Chemistry and Catalysis |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Photon
Materials science Sustainability and the Environment Band gap Renewable Energy Sustainability and the Environment Energy Engineering and Power Technology 02 engineering and technology Electron 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Two-photon absorption Molecular physics 0104 chemical sciences Fuel Technology Chemistry (miscellaneous) Materials Chemistry Charge carrier Renewable Energy Thin film 0210 nano-technology Absorption (electromagnetic radiation) Excitation |
| Zdroj: | ACS Energy Letters, 5(12) ACS Energy Letters, 5(12), 3821. American Chemical Society |
| ISSN: | 2380-8195 |
| Popis: | To further understand the optoelectronic properties of metal halide perovskites, we investigate sub-bandgap absorption in methylammonium lead iodide (MAPbI3) films. Charge carrier dynamics are studied using time-resolved microwave conductivity measurements using sub-bandgap excitation. From changes in the decay dynamics as a function of excitation energy and intensity, we have identified three regimes: (i) Band-like charge transport at photon energies above 1.48 eV; (ii) a transitional regime between 1.48 and 1.40 eV; and (iii) below 1.40 eV localized optically active defects (8 × 1013 cm-3) dominate the absorption at low intensities, while two-photon absorption is observed at high intensities. We determined an Urbach energy of approximately 11.3 meV, indicative of a low structural and/or thermal disorder. Surprisingly, even excitation 120 meV below the bandgap leads to efficient charge transfer into electron (C60) or hole (spiro-OMeTAD) transport layers. Therefore, we conclude that for MAPbI3, the band tail states do not lead to nonradiative losses. |
| Databáze: | OpenAIRE |
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