Yina Moon

Haze is a key parameter that characterizes the optical clarity of transmissive materials. In real‐world applications of organic electrochromic devices, however, the origin of haze formation and its connection to film morphology remain poorly understood, despite its significant impact on user safety and visual comfort. This study elucidates the origin of haze formation in electrochromic polymer (ECP) films by analyzing the morphology of a propylenedioxythiophene (ProDOT)‐based ECP‐black, a broadband, neutral density, absorbing ECP that is one of the most important in electrochromic field. ECP solutions were prepared with a controlled amount of antisolvent, followed by thermal annealing to tune the polymer morphology. Based on Mie scattering theory, surface roughness and polymer aggregate size are identified as the primary factors responsible for haze formation. In addition, haze is shown to vary with film thickness and aggregation‐induced microvoids. This work provides fundamental insight into haze formation in organic electrochromic films and establishes strategies for controlling haze that can impair device performance.

Carbon nanotubes have shown great promise for high-performance, large-area, solution processable field-effect transistors due to their exceptional charge transport properties. In this study, we utilize the spin-coating method to form networks from selectively sorted semiconducting single-walled carbon nanotubes (s-SWNTs), aiming for scalable electronic device fabrication. The one-dimensional nature of s-SWNTs, however, introduces significant roughness and charge trap sites, hindering charge transport due to the van der Waals gap (∼0.32 nm) between nanotubes. Addressing this, we explored the effects of anion doping on the spin-coated s-SWNT random network, with a focus on the influence of the small size of halogen anions (0.13–0.22 nm) on these electronic properties. Raman and ultraviolet–visible–near-infrared optical spectroscopy results indicate that smaller anions significantly enhance doping effects through strong non-covalent anion–π interactions, improving charge transport and carrier injection efficiency in s-SWNTs, especially for n-type operation. This improvement is inversely proportional to the size of the halogen anions, with the smallest anion (fluorine) effectively transitioning the electrical characteristics of the s-SWNT network from ambipolar to n-type by reducing both junction and contact resistances through anion doping, based on anion–π interaction.