Premium
Investigation of Interfacial Charge Separation at PbS QDs/(001) TiO 2 Nanosheets Heterojunction Solar Cell
Author(s) -
Ghadiri Elham,
Liu Bin,
Moser JacquesE.,
Grätzel Michael,
Etgar Lioz
Publication year - 2015
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201400210
Subject(s) - heterojunction , materials science , photocurrent , quantum dot , solar cell , optoelectronics , band gap , nanotechnology , nanoparticle , charge carrier , hybrid solar cell , energy conversion efficiency , polymer solar cell , chemical engineering , engineering
In the recent years, the heterojunction solar cells based on quantum dots (QDs) have attracted attention due to strong light absorbing characteristics and the size effect on the bandgap tuning. This paper reports on the kinetics of interfacial charge separation of PbS QDs/(001) TiO 2 nanosheets heterojunction solar cells. PbS QDs are deposited using a bifunctional linker molecule on two different TiO 2 films, i.e., TiO 2 nanosheets (with 001 dominant exposed facet) and TiO 2 nanoparticles (with 101 dominant exposed facet). Upon bandgap excitation, electrons are transferred from the PbS QDs conduction band to the lower lying conduction band of TiO 2 . Based on the ultrafast pump‐probe laser spectroscopy technique, the kinetics of charge separation is scrutinized at the PbS/TiO 2 interface. The interfacial charge separation at PbS/TiO 2 nanosheets films made of (001) dominant exposed facets is five times faster than that on (101) dominant exposed facets TiO 2 nanoparticles. The quantum yields for charge injection are higher for the (001) TiO 2 nanosheets than the (101) TiO 2 nanoparticles due to enhanced interfacial interaction with (001) surface compared to the (101) nanoparticles. The superior interfacial charge separation at PbS/(001) nanosheets respect to PbS/(101) nanoparticles is consistent with the higher photocurrent and enhanced power conversion efficiency in the PbS QDs/(001) TiO 2 heterojunction solar cell. The use of (001) TiO 2 nanosheets can be a better alternative to conventional mesoporous TiO 2 films in QD heterojunction solar cells and perovskites‐based heterojunction solar cells.