Spectroscopic Signature of Trap States in Assembled CdSe Nanocrystal Hybrid Films

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• 作者：Tersilla Virgili ; Inmaculada Su谩rez L贸pez ; Barbara Vercelli ; Giuliano Angella ; Gianni Zotti ; Juan Cabanillas-Gonzalez ; Daniel Granados ; Larry Luer ; Reinhold Wannemacher ; Francesco Tassone
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：August 2, 2012
• 年：2012
• 卷：116
• 期：30
• 页码：16259-16263
• 全文大小：261K
• 年卷期：v.116,no.30(August 2, 2012)
• ISSN：1932-7455

文摘

We report on femtosecond to millisecond pump鈥損robe experiments performed on a multilayered structure composed by the alternation of CdSe nanocrystals (NCs) and poly(p-styrenesulphonic acid) (PSSH). We found that, after a few picoseconds of pumping at high intensity, an intense photoinduced absorption band and a strong derivative feature emerge in the differential absorption spectrum, both overlapping with the positive bleaching bands of the filled exciton states. These two former spectral features are long-living well into the millisecond range, and we attribute them to the population of charged trap states, located close to the NC surface, and thus inducing a Stark effect through the strong electric field they generate inside the NC.