Issue 25, 2016

Ultrafast charge carrier dynamics in CH3NH3PbI3: evidence for hot hole injection into spiro-OMeTAD

Abstract

Hybrid organic–inorganic metal perovskites have emerged as highly promising materials for solar energy conversion. However, key questions regarding the working principles of perovskite solar cells remain to be answered in order to improve the design of such devices. In the present study, we have investigated the influence of excess excitation energy on the initial photo-products generated from FTO/meso-TiO2/CH3NH3PbI3 samples. We find that upon resonant excitation at the band edge, part of the formation of free charges passes via an excitonic state that dissociates on the sub-picosecond time scale. An exciton binding energy of <10 meV is estimated from the lifetime of the exciton. On the other hand, if excess energy is available, free charges are directly generated. We have then investigated the hole injection into spiro-OMeTAD at the CH3NH3PbI3/spiro-OMeTAD interface. By following spectroscopically the generation of the oxidized form of the molecular hole conductor spiro-OMeTAD, we confirm that the hole injection is essentially ultrafast and occurs on the sub-80 femtosecond time scale. On this time scale, the hole injection competes with carrier cooling after photo-excitation and therefore the charge injection can occur from non-thermalised states.

Graphical abstract: Ultrafast charge carrier dynamics in CH3NH3PbI3: evidence for hot hole injection into spiro-OMeTAD

Supplementary files

Article information

Article type
Paper
Submitted
13 جمادى الأولى 1437
Accepted
08 شعبان 1437
First published
09 شعبان 1437

J. Mater. Chem. C, 2016,4, 5922-5931

Ultrafast charge carrier dynamics in CH3NH3PbI3: evidence for hot hole injection into spiro-OMeTAD

J. C. Brauer, Y. H. Lee, M. K. Nazeeruddin and N. Banerji, J. Mater. Chem. C, 2016, 4, 5922 DOI: 10.1039/C6TC00763E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements