2024-03-29T08:07:50Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1479992017-12-18T13:54:22Zcom_10261_31com_10261_3col_10261_284
Garrot, D.
Castro, Miguel
Boukheddaden, K.
2017-04-06T07:52:58Z
2017-04-06T07:52:58Z
2015
Journal of Physical Chemistry C 119(41): 23638-23647 (2015)
http://hdl.handle.net/10261/147999
10.1021/acs.jpcc.5b06211
http://dx.doi.org/10.13039/501100004794
http://dx.doi.org/10.13039/501100001665
http://dx.doi.org/10.13039/501100003329
The performance of hybrid organic perovskite (HOP) for solar energy conversion is driving a renewed interest in their light emitting properties. The recent observation of broad visible emission in layered HOP highlights their potential as white-light emitters. Improvement of the efficiency of the material requires a better understanding of its photophysical properties. We present in-depth experimental investigations of white-light (WL) emission in thin films of the (C6H11NH3)2PbBr4. The broadband, strongly Stokes shifted emission presents a maximum at 90 K when excited at 3.815 eV, and below this temperature coexists with an excitonic edge emission. X-rays and calorimetry measurements exclude the existence of a phase transition as an origin of the thermal behavior of the WL luminescence. The free excitonic emission quenches at low temperature, despite a binding energy estimated to 280 meV. Time-resolved photoluminescence spectroscopy reveals the multicomponent nature of the broad emission. We analyzed the dependence of these components as a function of temperature and excitation energy. The results are consistent with the existence of self-trapped states. The quenching of the free exciton and the thermal evolution of the WL luminescence decay time are explained by the existence of an energy barrier against self-trapping, estimated to ∼10 meV.
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Optical investigation of broadband white-light emission in self-assembled organic-inorganic perovskite (C6H11NH3)2PbBr4
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