Foldable Perovskite Solar Cells Using Carbon Nanotube‐Embedded Ultrathin Polyimide Conductor

Abstract

Recently, foldable electronics technology has become the focus of both academic and industrial research. The foldable device technology is distinct from flexible technology, as foldable devices have to withstand severe mechanical stresses such as those caused by an extremely small bending radius of 0.5 mm. To realize foldable devices, transparent conductors must exhibit outstanding mechanical resilience, for which they must be micrometer‐thin, and the conducting material must be embedded into a substrate. Here, single‐walled carbon nanotubes (CNTs)–polyimide (PI) composite film with a thickness of 7 µm is synthesized and used as a foldable transparent conductor in perovskite solar cells (PSCs). During the high‐temperature curing of the CNTs‐embedded PI conductor, the CNTs are stably and strongly p‐doped using MoOx, resulting in enhanced conductivity and hole transportability. The ultrathin foldable transparent conductor exhibits a sheet resistance of 82 Ω sq.−1 and transmittance of 80% at 700 nm, with a maximum‐power‐point‐tracking‐output of 15.2% when made into a foldable solar cell. The foldable solar cells can withstand more than 10 000 folding cycles with a folding radius of 0.5 mm. Such mechanically resilient PSCs are unprecedented; further, they exhibit the best performance among the carbon‐nanotube‐transparent‐electrode‐based flexible solar cells.

Perovskite/Si tandem solar cells: Fundamentals, advances, challenges, and novel applications

“…It requires both high transparency and conductivity. Various transparent conductive materials have been employed as electrode for perovskite solar cells including thin metal layer, Ag nanowire, carbon nanotube, graphene, and TCOs 107–110 . Among these, TCOs such as ITO has been evidenced to be a promising top electrode for semitransparent perovskite cells by significantly improving the device lifetime 37 .…”

“…Various transparent conductive materials have been employed as electrode for perovskite solar cells including thin metal layer, Ag nanowire, carbon nanotube, graphene, and TCOs. [107][108][109][110] Among these, TCOs such as ITO has been evidenced to be a promising top electrode for semitransparent perovskite cells by significantly improving the device lifetime. 37 Generally, the ITO made by industrial sputtering technique are widely used in Si-based PV technology.…”

Highly Foldable Perovskite Solar Cells Using Embedded Polyimide/Silver Nanowires Conductive Substrates

“…By now, only a few foldable PSCs were reported through the construction of device structure to relieve strain and the substitution of brittle ITO electrodes. [ 15–17 ] Li et al. applied the strategies of using 25 µm ultrathin substrate to relieve strain, combined with the ultrathin silver electrodes to replace ITO, composing the foldable PSCs which could work after 50 folding cycles.…”

“…realized the foldable PSCs using 7 µm embedded carbon nanotubes/polyimide (PI) conductive substrates, which could tolerate folding with a radius of 0.5 mm for over 10 000 cycles. [ 17 ] Moreover, Lee et al. adopted the strategies of using ultrathin substrates and protective layer to reduce strain, combined with conducting polymer electrodes to replace ITO, resulting in the foldable PSCs which could tolerate 10 000 bending cycles at a radius of 0.5 mm and even 100 crumpling cycles.…”

Porous Ga2O3 Nanotubes Derived from Urease‐Mediated Interfacially‐Grown NH4Ga(OH)2CO3 for High‐Efficient Hydrogen Evolution

“…Nanotubes have aroused intense interests among the fields of catalysis, [1][2][3][4] biomedicine, [5][6][7] electronics, [8,9] and ecology, [10] owing to the intrinsic merits of the large surface areas with abundant active sites for adsorptions and catalytic reactions, the easy modifiable inner and external surface, the short distance of the thin-wall for fast mass-transfer and photocarriers transport, and the high efficient utilization of light irradiation Dedicated to the 100th Anniversary of Chemistry at Nankai University proposed strategy is simple, applicable for synthesis of the doped NH 4 Ga(OH) 2 CO 3 nanotubes, and massive production of Ga 2 O 3 and doped Ga 2 O 3 nanotubes.…”