Hybrid heterojunction solar cells based on single-walled carbon nanotubes and amorphous silicon thin films

Funding Information: Jane ja Aatos Erkon Säätiö, Grant/Award Number: 700056 T30404; Ministry of Education and Science of the Russian Federation, Grant/Award Number: FZSR‐2020‐0007; Opetushallitus, Grant/Award Number: TM‐19‐11028; Russian Foundation for Basic Research, Grant/Award Number: 18‐29‐19169 Funding information Funding Information: Pramod M. Rajanna and Peter D. Lund acknowledge the ASPIRE funded by Jane and Aatos Erkko Foundation (project # 700056 T30404), Finland. This work was supported by the Ministry of Science and Higher Education of the Russian Federation (project no. FZSR‐2020‐0007 in the framework of the state assignment no. 075‐03‐2020‐097/1). Albert G. Nasibulin acknowledges the Russian Foundation for Basic Research (project no. 18‐29‐19169). Pramod M. Rajanna thanks for the partial financial support from EDUFI Fellowship (# TM‐19‐11028) from Finnish National Agency for Education. Publisher Copyright: © 2021 The Authors. WIREs Energy and Environment published by Wiley PeriodicalsLLC. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.Hybrid heterojunction solar cells based on silicon and single-walled carbon nanotube (SWCNT) thin films have a simple structure and their manufacture employ simple low-temperature processes. Moreover, their progress has been rapid during the last decade, wherein the efficiency of heterojunction solar cells combining hydrogenated amorphous silicon (a-Si:H) and SWCNTs thin film has increased from 0.03% to 8.80%. Here, we present a comprehensive overview of the state-of-the-art on SWCNTs/a-Si:H heterojunction solar cells. In addition to a comprehensive technology review, important special features such as adhesion of SWCNT film to a-Si:H, the interface between SWCNT and a-Si:H, and their influence on the performance of the heterojunctions are included. Future paths for improving the performance of such solar cells are also suggested. Finally, key challenges and trends for further research and development of SWCNTs/amorphous silicon heterojunction solar cells are discussed. This article is categorized under: Photovoltaics > Science and Materials.Peer reviewe

Surface Passivation for Efficient Bifacial HTL-free Perovskite Solar Cells with SWCNT Top Electrodes

Publisher Copyright: © 2021 American Chemical Society.Building-integrated photovoltaics is an emerging field that demands approaches to deliver efficient and flexible photovoltaic cells at a low cost. In this work, high-quality single-walled carbon nanotube (SWCNT) films were utilized as an electrode for the hole-transport-layer (HTL)-free perovskite solar cells using a methodology compatible with scalable low-temperature roll-to-roll fabrication. We report a simple passivation strategy of the perovskite/SWCNT interface using methylammonium iodide, which dramatically enhances the performance of the cells, delivering power conversion efficiencies of up to 16.7%. We believe that the device configuration presented here will facilitate the development of a generation of bifacial perovskite solar cells for integrated photovoltaics and tandems.Peer reviewe

Rational design of highly efficient flexible and transparent p-type composite electrode based on single-walled carbon nanotubes

Transparent electrodes are of great importance in electronics and energy technologies. At present, transparent conductive oxides are mainly n-type conductors dominating the market and have restricted the technological advancements. Single-walled carbon nanotubes (SWCNTs) have recently emerged as promising p-type transparent conductor owing to their superior hole mobility, conductivity, transparency, flexibility and possibility to tune the work function. Here, we develop a novel rational design of p-type flexible transparent conductive film (TCF) based on SWCNTs combined with poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), molybdenum oxide and SWCNT fibers. In a configuration of SWCNTs-MoO3-PEDOT:PSS/SWCNT fibers, we achieved a record equivalent sheet resistance of 17 Ω/sq with a transmittance of 90% at 550 nm and a high degree of flexibility. We demonstrate that our solar cells developed on the basis of the proposed electrode and hydrogenated amorphous silicon (a-Si:H) yield an outstanding short-circuit current density of Jsc = 15.03 mA/cm2 and a record power conversion efficiency of PCE = 8.8% for SWCNTs/a-Si:H hybrid solar cells. We anticipate that this novel rationally designed p-type TCF opens a new avenue in widespread energy technologies, where high hole conductivity and transparency of the material are prerequisites for their successful implementation.Peer reviewe

Adhesion of Single-Walled Carbon Nanotube Thin Films with Different Materials

Single-walled carbon nanotubes (SWCNTs) possess extraordinary physical and chemical properties. Thin films of randomly oriented SWCNTs have great potential in many opto-electro-mechanical applications. However, good adhesion of SWCNT films with a substrate material is pivotal for their practical use. Here, for the first time, we systematically investigate the adhesion properties of SWCNT thin films with commonly used substrates such as glass (SiO2), indium tin oxide (ITO), crystalline silicon (C-Si), amorphous silicon (a-Si:H), zirconium oxide (ZrO2), platinum (Pt), polydimethylsiloxane (PDMS), and SWCNTs for self-adhesion using atomic force microscopy. By comparing the results obtained in air and inert Ar atmospheres, we observed that the surface state of the materials greatly contributes to their adhesion properties. We found that the SWCNT thin films have stronger adhesion in an inert atmosphere. The adhesion in the air can be greatly improved by a fluorination process. Experimental and theoretical analyses suggest that adhesion depends on the atmospheric conditions and surface functionalization.Peer reviewe

Novel design strategy for GaAs-based solar cell by application of single-walled carbon nanotubes topmost layer

Attempts to improve solar cells efficiency touch all its constituents and are directly related to their fabrication protocols. While the most promising material platform for high efficiency photovoltaic devices is still III-V semiconductors, introduction of novel materials like single-walled carbon nanotubes (SWCNTs), which are characterized by unique combination of conductivity and transparency, might greatly yield the device performance. Here, for the first time, we present the results of the fabrication and characterization of a thin-film GaAs solar cell with a SWCNT top contact. We examine the contact between the SWCNT film and the semiconductor structure by means of the optical and electron beam-induced current techniques. The fabricated device demonstrates better performance, that is, increased power conversion efficiency from 10.6% to 11.5% when compared to the cell with the traditional metal contact grid, stemming from the enhanced photocurrent collection efficiency and low parasitic light absorption in the emitter layer. We envision future prospects to exploit the multifunctionality of the SWCNTs in fabrication of highly efficient photovoltaic devices including flexible solar cells.Peer reviewe