Ultra‐Thin Polyimide‐Embedded Carbon Nanotube‐Based Transparent Conductor and Its Application to Foldable Perovskite Solar Cells

Ultra‐thin (~2.0 μm) carbon nanotube‐embedded polyimide (CNT–PI) transparent conducting substrates were fabricated by blending two complementary polyimide (PI) precursors, anhydrous dimethylacetamide (DMAc)‐based and N ‐methyl‐2‐pyrrolidone (NMP)‐based systems at an optimized ratio prior to imidization. The DMAc‐based PI, synthesized from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride and 2,2′‐bis(trifluoromethyl)benzidine, provides optical transparency and color neutrality through its charge‐transfer complexes suppressing fluorinated architecture. In contrast, the NMP‐based PI, synthesized from pyromellitic dianhydride and 4,4′‐oxydianiline, contributes mechanical robustness via efficient chain packing. The resulting hybrid CNT–PI films exhibit transmittance of ~90% at 600 nm, Young's modulus of ~ 5 MPa, glass‐transition temperature ( T g ) of 264.5 °C, and near‐complete color neut…