Dynamic Microscopy Study of Ultrafast Charge Transfer in a Hybrid P3HT/Hyperbranched CdSe Nanoparticle Blend for Photovoltaics.
We present a spectroscopic investigation on a new hyperbranched cadmium selenide nanocrystals (CdSe NC)/poly(3-hexylthiophene) (P3HT) blend, a potentially good active component in hybrid photovoltaics. Combined ultrafast transient absorption spectroscopy and morphological investigations by means of an ultrafast confocal microscope reveal a strong influence of the complex local structure on the photogenerated carrier dynamics. In particular, we map the electron-transfer process across the hybrid NC/polymer interface, and we reveal that charge separation occurs through a preferential pathway from the CdSe nanobranches to the P3HT chains. Efficient charge generation at the distributed heterojunction is also confirmed by scanning kelvin probe force microscopy measurements.
†Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy.|#Center for Nano Science and Technology @ PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
Giulia
G
Grancini
‡NNL-CNR Nanoscience Institute c/o Dip. Fisica Ed. G. Marconi, La Sapienza University, Roma, Italy.|§Electronical Engineering Department, Tor Vergata University, Via del Politecnico, 00133 Roma, Italy.
Mariano
M
Biasiucci
⊥NNL-CNR Nanoscience Institute, Dip. Ingegneria Innovazione, Università del Salento, via Arnesano, 73100 Lecce, Italy.
Rosanna
R
Mastria
†Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy.
Francesco
F
Scotognella
#Center for Nano Science and Technology @ PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
Francesco
F
Tassone
†Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy.
Dario
D
Polli
⊥NNL-CNR Nanoscience Institute, Dip. Ingegneria Innovazione, Università del Salento, via Arnesano, 73100 Lecce, Italy.|∥CNR, Ist Nanosci, NNL, I-73100 Lecce, Italy.
Giuseppe
G
Gigli
†Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy.|#Center for Nano Science and Technology @ PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy.
Guglielmo
G
Lanzani
Transient absorption imaging; charge dynamics; hybrid photovoltaics; interfaces; nanocrystals