Recent Advances in Carbon Nanotube Utilization in Perovskite Solar Cells: A Review

Abstract

Due to their exceptional optoelectronic properties, halide perovskites have emerged as prominent materials for the light-absorbing layer in various optoelectronic devices. However, to increase device performance for wider adoption, it is essential to find innovative solutions. One promising solution is incorporating carbon nanotubes (CNTs), which have shown remarkable versatility and efficacy. In these devices, CNTs serve multiple functions, including providing conducting substrates and electrodes and improving charge extraction and transport. The next iteration of photovoltaic devices, metal halide perovskite solar cells (PSCs), holds immense promise. Despite significant progress, achieving optimal efficiency, stability, and affordability simultaneously remains a challenge, and overcoming these obstacles requires the development of novel materials known as CNTs, which, owing to their remarkable electrical, optical, and mechanical properties, have garnered considerable attention as potential materials for highly efficient PSCs. Incorporating CNTs into perovskite solar cells offers versatility, enabling improvements in device performance and longevity while catering to diverse applications. This article provides an in-depth exploration of recent advancements in carbon nanotube technology and its integration into perovskite solar cells, serving as transparent conductive electrodes, charge transporters, interlayers, hole-transporting materials, and back electrodes. Additionally, we highlighted key challenges and offered insights for future enhancements in perovskite solar cells leveraging CNTs.

Keywords: carbon nanotubes; conducting substrate; green energy; perovskite solar cells.

Figure 1

(a) A multi-walled carbon nanotube structure composed of three shells of varying chirality. (b) A graphene sheet is rolled up, resulting in three distinct forms of CNTs. Reproduced with permission from [56]. Copyright (2004) John Wiley and Sons.

Figure 2

(a) Schematic of AD apparatus for synthesizing SWCNTs and MWCNTs. (b) SEM images of carbon nanotube. Reproduced with permission from [61]. Copyright (2016) Springer Nature.

Figure 3

(a) Schematic depiction of novel synergistic routes for the electrolysis of CNT “wool” of a macroscopic length in molten carbonate, leading to a high yield. Reproduced with permission from [71]. Copyright (2017) Elsevier. (b) Methods for producing CNTs in solutions containing either pure Li₂CO₃ or salts including alkaline earth carbonate. Reproduced with permission from [72]. Copyright (2019) IOP Publishing.

Figure 4

(a) Schematic showing the synthesis of CNTs by FCCVD, and (b–e) various ways of introducing the catalyst into the reactor: supersaturated vapor. Reproduced with permission from [75]. Copyright (2019) John Wiley and Sons.

Figure 5

(a) HTM chemical structures, (b) design of inverted planar perovskite solar cells, (c) PCE, (d) V_oc, and (e,f) J_sc of device. Reproduced with permission from [131]. Copyright (2019) Royal Society of Chemistry.

Figure 6

(a) A three-dimensional rendering of a PSC device using a transparent electrode made of calcinated DWNT. (b) Interfacial energy diagram of DWNTs, PTAA, and perovskites. (c) PL quenching of the perovskite layer (PVK) on DWNT doped with triflic acid (black), DVNT doped with triflic acid (red), DWNT doped with triflic acid (blue), and DWNT doped with triflic acid (khaki) after being calcinated at 300 °C, 400 °C, and 500 °C, respectively. The photovoltaic parameters of the PSCs based on (d) triflic acid-doped pristine DWNT, (e) triflic acid-doped 300 °C-calcinated DWNT, (f) triflic acid-doped 400 °C-calcinated DWNT, and (g) triflic acid-doped 500 °C-calcinated DWNT were determined by observing the J-V forward and reverse bias curves under AM 1.5 G one-sun illumination. Reproduced with permission from [147]. Copyright (2021) John Wiley and Sons.

Figure 7

(a) A schematic showing how the gadgets built for this research are structured. (b) PSC J-V graphs. (c) Electron spin resonance spectra of doped and undoped PSCs. (d) Effects of hysteresis on PSCs containing pure ZnO and ZnO with 2% CNT. Reproduced with permission from [167]. Copyright (2019) Royal Society of Chemistry.

Figure 8

(a) The design of the device at the perovskite/carbon electrode interface for C-PSCs with implanted PEI/CNT bridging. (b) A schematic showing the charge transfer mechanism from perovskite to carbon electrode using PEI/CNT as the bridge, and perovskite surface trap state passivation molecules also appear in the schematic. (c) Artificially prepared PEI-functionalized carbon nanotubes. Reproduced with permission from [180]. Copyright (2019) Royal Society of Chemistry.