Carbon Nanotube Electrode‐Based Perovskite–Silicon Tandem Solar Cells

Abstract

Carbon nanotube electrode–laminated perovskite solar cells in combination with n‐type tunnel oxide–passivated contact silicon solar cells demonstrate a high power conversion efficiency (PCE) of 24.42% when stacked in tandem. This is compared with conventional indium tin oxide/MoOx‐deposited perovskite solar cells which give an efficiency of 22.35% when stacked in the same four‐terminal tandem system. Despite higher transmittance of the carbon nanotube electrode than that of the indium tin oxide/MoOx in the infrared range, the carbon nanotube electrode‐laminated devices show lower transmittance in the same region due to the total internal reflection and scattering as evidenced by optical simulation. Yet, the exceptionally high PCE of the carbon nanotube electrode‐laminated semitransparent devices far exceeding than that of the indium tin oxide/MoOx‐deposited semitransparent top cell outweighs the effect of the optical transparency. Four types of silicon solar cells are compared as the bottom subcells, and the n‐type tunnel oxide‐passivated contact silicon solar cells are the best choice mainly due to their high absorption in the long‐wavelength region. The obtained 24.42% efficiency is one of the high PCEs among the reported four‐terminal perovskite–silicon solar cells, and this article is the first demonstration of the carbon nanotube electrode application in tandem solar cells.

Semitransparent Perovskite Solar Cells for Building Integration and Tandem Photovoltaics: Design Strategies and Challenges

“…For this reason, there has been a growing research interest in alternative materials to serve as transparent electrodes, such as ultrathin metal (UTM) films, [ 90–94 ] multilayered dielectric/metal/dielectric (DMD) structures, [ 95–100 ] metal nanowires, [ 101–103 ] conductive polymers, [ 104,105 ] graphene, [ 106–109 ] and carbon nanotubes (CNTs). [ 110,111 ] The pros and cons related to their use as TTEs compared to TCOs, as well as their performances in terms of sheet resistance (R s ) and average transmittance ( T avg ) based on recent reports, are listed in Table 1 .…”

“…Very recently, a CNT electrode was implemented for the first time to 4‐terminal perovskite/silicon tandem cells, proving to be an ideal candidate as TTE for tandem purposes due to its higher transmittance than the ITO electrodes in the infrared region. [ 111 ] Taking advantage of its atomic‐scale flatness, You and others reported the employ of graphene as TTE; the stacked multilayered graphene was prepared by chemical vapor deposition (CVD) followed by a lamination procedure [ 106 ] ; a thin layer of PEDOT:PSS was coated onto the electrode both to improve the electrical conductivity and contribute to the formation of an efficient interface with the perovskite film. More specific examples of application of different transparent electrodes as TTEs in ST‐PSCs will be provided in the next two sections, where a clear boundary between BIPV and tandem applications will be drawn.…”

Multi-Walled Carbon Nanotube-Assisted Encapsulation Approach for Stable Perovskite Solar Cells

“…Organohalide perovskite materials have attracted considerable attention, especially in the application of energy harvesting [ 1 , 2 ]. When applied in photovoltaics, these materials yield a high-power conversion efficiency owing to their outstanding properties, namely their wide range of light absorption and long exciton diffusion length [ 3 , 4 ]. Despite the high efficiency of perovskite solar cells (PSCs), insufficient device stability has been the limiting factor in commercialisation.…”

Improved Nanophotonic Front Contact Design for High‐Performance Perovskite Single‐Junction and Perovskite/Perovskite Tandem Solar Cells

“…[18,19] In addition, the tunable optical bandgap of perovskite materials makes them very suitable to realize highly efficient perovskite-based tandem solar cells (PVK TSCs). [5,11,20,21] According to the detailed balance (DB) theorem, the PCE of TSCs can go beyond 40% by selecting absorber materials with optimum bandgaps. [10,19] In a typical PSC, the perovskite absorber is placed between the electron transport layer (ETL) and the hole transport layer (HTL), where the ETL plays a significant role in achieving high-performance devices.…”