info:eu-repo/semantics/article
Femtosecond Charge-Injection Dynamics at Hybrid Perovskite Interfaces
Fecha
2017-09Registro en:
Grancini, Giulia; Viola, Daniele; Lee, Yonghui; Saliba, Michael; Paek, Sanghyun; et al.; Femtosecond Charge-Injection Dynamics at Hybrid Perovskite Interfaces; Wiley VCH Verlag; Chemphyschem; 18; 17; 9-2017; 2381-2389
1439-4235
1439-7641
CONICET Digital
CONICET
Autor
Grancini, Giulia
Viola, Daniele
Lee, Yonghui
Saliba, Michael
Paek, Sanghyun
Cho, Kyung Taek
Orlandi, Simonetta
Cavazzini, Marco
Fungo, Fernando Gabriel
Hossain, Mohammad I.
Belaidi, Abdelhak
Tabet, Nouar
Pozzi, Gianluca
Cerullo, Giulio
Nazeeruddin, Mohammad Khaja
Resumen
With a power conversion efficiency (PCE) exceeding 22 %, perovskite solar cells (PSCs) have thrilled photovoltaic research. However, the interface behavior is still not understood and is a hot topic of research: different processes occur over a hierarchy of timescales, from femtoseconds to seconds, which makes perovskite interface physics intriguing. Herein, through femtosecond transient absorption spectroscopy with spectral coverage extending into the crucial IR region, the ultrafast interface-specific processes at standard and newly molecularly engineered perovskite interfaces in state-of-the-art PSCs are interrogated. Ultrafast interfacial charge injection occurs with a time constant of 100 fs, resulting in hot transfer from energetic charges and setting the timescale for the first step involved in the complex charge-transfer process. This is also true for 20 % efficient devices measured under real operation, for which the femtosecond injection is followed by a slower picosecond component. These findings provide compelling evidence for the femtosecond interfacial charge-injection step and demonstrate a robust method for the straightforward identification of interfacial non-equilibrium processes on the ultrafast timescale.