Boronic acid-containing polycyclosiloxane showed unique self-assembly nanofilm formation (6 nm film thickness) on various substrates and provided film-based metal ion sensor capability through dynamic covalent bonding.

The Piers–Rubinsztajn (PR) reaction catalyzed by a metal-free B­(C6F5)3 catalyst was reported as efficient in synthesizing novel polysiloxanes through polycondensation of dialkoxylsilanes and dihydrosiloxane monomers at room temperature. This study is aimed at developing new cyclosiloxane polymers having no hydrocarbon linker in the main chain via an equimolar PR reaction between tetrafunctional eight-membered cyclosiloxanes (TMCS) having the four reactive silyl hydrides (Si–H) at the Si vertices and bifunctional dialkoxylsilanes. The final polymers were targeted with the remaining Si–H group at the Si vertices of the TMCS repeating units for post-functionalization, good solubility in typical organic solvents for post-processing, and a stable ring structure in TMCS for outstanding macromolecular flexibility. However, hydride transfer ring-opening polymerization (HTRP) of TMCS was reported in the B­(C6F5)3-catalyzed reaction system, which invariably causes uncontrollable gelation. Suppression of HTRP succeeded via control of total monomer concentration and reaction time reduction, thereby obtaining post-processable and post-functionalizable liquid cyclosiloxane prepolymers. Thermal curing of the prepolymers through self-cross-linking of the remaining reactive Si–H groups gave rise to free-standing films with excellent thermal stability exceeding 600 °C and a low dielectric constant. The functional versatility of the Si–H groups produces promising prepolymers for creating various functional materials.

Dithiocarbonate‐based non‐hygroscopic polymers with a glass transition temperature (Tg) and polydispersity index (PDI) of ≈4 °C and 1, respectively, are synthesized through living cationic ring‐opening polymerization. These liquid‐state polymers are characterized by monodispersity based on the low Tg and PDI, rendering remarkable miscibility with the perovskite precursors without aggregation. Accordingly, these polymers are added to perovskite solar cells (PSCs) to enhance their power conversion efficiency (PCE). The PCE of reference PSCs increases from 19.70% to 23.52% after direct addition of the synthesized polymer. This efficiency improvement is attributed to the considerable increases in short‐circuit current density (JSC) and fill factor (FF), resulting from the augmented size and defect passivation of perovskite crystals induced by added polymers. In fact, the PCE and JSC of the devices measured in the laboratory and the certification center are the highest among the reported polymer‐added PSCs, thanks to the great miscibility of the new polymers leading to the large amount addition which enables more thorough passivation among the grain boundaries. The improvement in open‐circuit voltage falls short as compared to that in JSC and FF, ascribed to the relatively moderate interaction strength between perovskite materials and dithiocarbonate groups.

Single-walled carbon nanotubes (SWCNTs) are representative one-dimensional materials that show exceptional optical and electronic properties with various tuneable bandgaps. SWCNTs can be integrated into a variety of photovoltaics particularly, perovskite solar cells (PSCs) based on a high level of functionality and purity. In this topical review, we discuss the fundamentals of SWCNTs applied to PSCs as an electron-transporting layer (ETL), hole-transporting layer (HTL), photoactive layer, and interfacial materials from the literature. Firstly, SWCNTs in PSCs and their defect control properties improving the devices are discussed. Subsequently, electrical and morphological improvement of semiconducting SWCNT (S-SWCNT)-added PSCs and other types of CNTs used in PSCs are discussed chronologically. The review and discussion layout the strategies of incorporating SWCNTs within the design frame of next-generation PSCs towards the improvement of the device performance via defect passivation.