Open AccessMolecular-structure Control of Ultrafast Electron Injection at Cationic Porphyrin–CdTe Quantum Dot Interfaces
Author(s) -
Shawkat M. Aly,
Ghada Ahmed,
Basamat S. Shaheen,
Jingya Sun,
Omar F. Mohammed
Publication year - 2015
Publication title -
the journal of physical chemistry letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.563
H-Index - 203
ISSN - 1948-7185
DOI - 10.1021/acs.jpclett.5b00235
Subject(s) - porphyrin , quantum dot , ultrafast laser spectroscopy , ultrashort pulse , cadmium telluride photovoltaics , materials science , electron transfer , photovoltaics , optoelectronics , electron , spectroscopy , nanotechnology , photochemistry , chemical physics , chemistry , photovoltaic system , optics , physics , laser , ecology , quantum mechanics , biology
Charge transfer (CT) at donor (D)/acceptor (A) interfaces is central to the functioning of photovoltaic and light-emitting devices. Understanding and controlling this process on the molecular level has been proven to be crucial for optimizing the performance of many energy-challenge relevant devices. Here, we report the experimental observations of controlled on/off ultrafast electron transfer (ET) at cationic porphyrin-CdTe quantum dot (QD) interfaces using femto- and nanosecond broad-band transient absorption (TA) spectroscopy. The time-resolved data demonstrate how one can turn on/off the electron injection from porphyrin to the CdTe QDs. With careful control of the molecular structure, we are able to tune the electron injection at the porphyrin-CdTe QD interface from zero to very efficient and ultrafast. In addition, our data demonstrate that the ET process occurs within our temporal resolution of 120 fs, which is one of the fastest times recorded for organic photovoltaics.