4 research outputs found
Multiscale approaches to high efficiency photovoltaics
While renewable energies are achieving parity around the globe, efforts to
reach higher solar cell efficiencies becomes ever more difficult as they
approach the limiting efficiency. The so-called third generation concepts
attempt to break this limit through a combination of novel physical processes
and new materials and concepts in organic and inorganic systems. Some examples
of semi-empirical modelling in the field are reviewed, in particular for
multispectral solar cells on silicon (french ANR project MULTISOLSI). Their
achievements are outlined, and the limits of these approaches shown. This
introduces the main topic of this contribution, which is the use of multiscale
experimental and theoretical techniques to go beyond the semi-empirical
understanding of these systems. This approach has already led to great advances
at modelling which have led to modelling software which is widely known. Yet a
survey of the topic reveals a fragmentation of efforts across disciplines,
firstly, such as organic and inorganic fields, but also between the high
efficiency concepts such as hot carrier cells and intermediate band concepts.
We show how this obstacle to the resolution of practical research obstacles may
be lifted by inter-disciplinary cooperation across length scales, and across
experimental and theoretical fields, and finally across materials systems. We
present a European COST Action MultiscaleSolar kicking off in early 2015 which
brings together experimental and theoretical partners in order to develop
multiscale research in organic and inorganic materials. The goal of this
defragmentation and interdisciplinary collaboration is to develop understanding
across length scales which will enable the full potential of third generation
concepts to be evaluated in practise, for societal and industrial applications.Comment: Draft paper accompanying a plenary presentation to the World
Renewable Energy Conference WREC 2015, June 2015, Bucharest. In press (IOP
Multiscale approaches to high efficiency photovoltaics
While renewable energies are achieving parity around the globe, efforts to reach higher solar cell efficiencies becomes ever more difficult as they approach the limiting efficiency. The so-called third generation concepts attempt to break this limit through a combination of novel physical processes and new materials and concepts in organic and inorganic systems. Some examples of semi-empirical modelling in the field are reviewed, in particular for multispectral solar cells on silicon (French ANR project MultiSolSi). Their achievements are outlined, and the limits of these approaches shown. This introduces the main topic of this contribution, which is the use of multiscale experimental and theoretical techniques to go beyond the semi-empirical understanding of these systems. This approach has already led to great advances at modelling which have led to modelling software, which is widely known. Yet, a survey of the topic reveals a fragmentation of efforts across disciplines, firstly, such as organic and inorganic fields, but also between the high efficiency concepts such as hot carrier cells and intermediate band concepts. We show how this obstacle to the resolution of practical research obstacles may be lifted by inter-disciplinary cooperation across length scales, and across experimental and theoretical fields, and finally across materials systems. We present a European COST Action “MultiscaleSolar” kicking off in early 2015, which brings together experimental and theoretical partners in order to develop multiscale research in organic and inorganic materials. The goal of this defragmentation and interdisciplinary collaboration is to develop understanding across length scales, which will enable the full potential of third generation concepts to be evaluated in practise, for societal and industrial applications
Hybrid Carbon Nanotubes−TiO2 Photoanodes for High Efficiency Dye-Sensitized Solar Cells
We describe a fast and effective procedure for
the preparation of high efficiency hybrid photoanodes for dye-
sensitized solar cells (DSCs), based on nanocrystalline TiO2
with limited addition of multiwall carbon nanotubes (CNTs).
The mixing process between CNTs and TiO2 nanoparticles is
almost instantaneous, which makes it feasible for large-scale
fabrication. Enhanced electron lifetime and reduced charge
recombination lead to highly increased short circuit current
density and overall photoconversion efficiency (from 13.6 mA
cm−2 to 16.0 mA cm−2 and from 7.0% to 9.0%, respectively, considering the bare TiO2 and the optimum CNTs concentration, which is 0.010 wt %), while the small reduction in open circuit photovoltage does not significantly affect cell performances. This result is remarkable since a standard dye molecule (N719) was used and no chemical treatments of the photoanodes prior to cell fabrication were applied (i.e., soaking in TiCl4 to boost open circuit photovoltage)