in this field as represented in Figure 2 and is broadly divided into two halves. The first half presents some essential background information on carbon nanotubes, particularly in relevance to their role in these kinds of solar cells, as well as a consideration of aspects such as thin film properties, device stability, scale-up, and operating mechanism, while the second half deals with the factors involved in improving performance.This review has been constrained almost exclusively to covering developments in the field of carbon nanotubes interfaced with monocrystalline silicon, though the field is also informed by other work being done in the associated areas of graphene-silicon and conducting polymer-silicon solar cells, as well as the use of nanotube films interfaced with polycrystalline silicon and other semiconductors, perovskites, organic photovoltaics, and more. This is partly in the interests of being able to provide a useful and informative level of technical detail while keeping the work to a manageable and digestible size both for those already working in the field and those new to it. It is also because although there are many parallels between, for example, the nanotube-silicon and polymer-silicon or graphene-silicon works, there are several important and fundamental differences, not the least of which may be the potential complexity/diversity of the operating mechanism(s) in the nanotube-silicon case. For information on these and other related types of photovoltaic device architectures incorporating carbon nanotubes, we refer the reader to Zielke et al., [49] Wang et al., [50] and Arnold et al., [51] as well as Li et al. [52] which also includes an overview of the carbon nanotube-silicon architecture as a part of the broader carbon-silicon theme. Table S1 of the Supporting Information provides a detailed and comprehensive list of published works in the carbon nanotube-silicon field along with various performance measurements, device structure parameters, and material properties.
BackgroundAlthough once an exotic, poorly understood, and difficult to obtain material, carbon nanotubes are now relatively well known, well understood, and widely available from commercial suppliers. Briefly, single-walled carbon nanotubes (SWCNT) are very high aspect ratio cylinders of graphene in which the Heterojunctions of carbon nanotubes interfaced with silicon respond to light illumination and can be operated in the power regime as solar cells. Very significant advances have been made in the last 5 years both in terms of headline performance values and in fundamental understanding of the underlying operating principles, as well as the sophistication of the devices and studies being reported. The body of literature is growing rapidly, and the latest power conversion efficiency and active area records have now reached over 17% and 2 cm 2 , respectively. Thus, the authors believe that it is now a useful time for an evaluation of the current state-of-the-art and challenges going forward, as well as for a comprehensively ...
