2 research outputs found
Core–Shell Nanophosphor Architecture: Toward Efficient Energy Transport in Inorganic/Organic Hybrid Solar Cells
In this work, a core–shell
nanostructure of samarium phosphates encapsulated into a Eu<sup>3+</sup>-doped silica shell has been successfully fabricated, which has been
confirmed by X-ray diffraction, transmission electron microscopy (TEM),
and high-resolution TEM. Moreover, we report the energy transfer process
from the Sm<sup>3+</sup> to emitters Eu<sup>3+</sup> that widens the
light absorption range of the hybrid solar cells (HSCs) and the strong
enhancement of the electron-transport of TiO<sub>2</sub>/polyÂ(3-hexylthiophene)
(P3HT) bulk heterojunction (BHJ) HSCs by introducing the unique core–shell
nanoarchitecture. Furthermore, by applying femtosecond transient absorption
spectroscopy, we successfully obtain the electron transport lifetimes
of BHJ systems with or without incorporating the core–shell
nanophosphors (NPs). Concrete evidence has been provided that the
doping of core–shell NPs improves the efficiency of electron
transfers from donor to acceptor, but the hole transport almost remains
unchanged. In particular, the hot electron transfer lifetime was shortened
from 30.2 to 16.7 ps, i.e., more than 44% faster than pure TiO<sub>2</sub> acceptor. Consequently, a notable power conversion efficiency
of 3.30% for SmPO<sub>4</sub>@Eu<sup>3+</sup>:SiO<sub>2</sub> blended
TiO<sub>2</sub>/P3HT HSCs is achieved at 5 wt % as compared to 1.98%
of pure TiO<sub>2</sub>/P3HT HSCs. This work indicates that the core–shell
NPs can efficiently broaden the absorption region, facilitate electron-transport
of BHJ, and enhance photovoltaic performance of inorganic/organic
HSCs
Top-down Strategy toward Versatile Graphene Quantum Dots for Organic/Inorganic Hybrid Solar Cells
Metal oxide nanocrystals have been
pursued for various applications
in photovoltaics as a buffer layer. However, it remains a challenging
task to adjust their energy levels to achieve a better match of the
donor–acceptor system. Herein, we report the fabrication of
graphene quantum dots (GQDs) with bright blue photoluminescence by
a top-down strategy based on laser fragmentation with posthydrothermal
treatment. The GQDs demonstrate appropriate energy level positions
and are used as an intermediate buffer layer between TiO<sub>2</sub> and P3HT to form a cascade energy level architecture. The introduction
of the GQDs into a bulk heterojunction hybrid solar cell has led to
an enhancement of the power conversion efficiency