In the pursuit to better understand the mechanisms of perovskite solar cells we performed Raman and photoluminescence measurements of free-standing CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> films, comparing dark with working conditions. The films, grown on a glass substrate and sealed by a thin glass coverslip, were measured subsequent to dark and white-light pretreatments. The extremely slow changes we observe in both the Raman and photoluminescence cannot be regarded as electronic processes, which are much faster. Thus, the most probable explanation is of slow photoinduced structural changes. The CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> transformation between the dark and the light structures is reversible, with faster rates for the changes under illumination. The results seem to clarify several common observations associated with solar cell mechanisms, like performance improvement under light soaking. More important is the call for solar-cell-related investigation of CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> to take the photoinduced structural changes into consideration when measuring and interpreting the results.

Photoinduced reversible structural transformations in free-standing CH3NH3PbI3 perovskite films

Mosconi Edoardo;De Angelis Filippo
2015

Abstract

In the pursuit to better understand the mechanisms of perovskite solar cells we performed Raman and photoluminescence measurements of free-standing CH3NH3PbI3 films, comparing dark with working conditions. The films, grown on a glass substrate and sealed by a thin glass coverslip, were measured subsequent to dark and white-light pretreatments. The extremely slow changes we observe in both the Raman and photoluminescence cannot be regarded as electronic processes, which are much faster. Thus, the most probable explanation is of slow photoinduced structural changes. The CH3NH3PbI3 transformation between the dark and the light structures is reversible, with faster rates for the changes under illumination. The results seem to clarify several common observations associated with solar cell mechanisms, like performance improvement under light soaking. More important is the call for solar-cell-related investigation of CH3NH3PbI3 to take the photoinduced structural changes into consideration when measuring and interpreting the results.
2015
Istituto di Scienze e Tecnologie Molecolari - ISTM - Sede Milano
illumination
photoluminescence
Raman
solar cell
thin film
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/311009
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 196
  • ???jsp.display-item.citation.isi??? ND
social impact