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Polymer doping is a significant approach to precisely control nucleation and crystal growth of perovskites and enhance electronic quality in perovskite solar cells (PSC) prepared in air. Here, a brand‐new self‐healing polysiloxane (SHP) with dynamic 2,6‐pyridinedicarboxamide (PDCA) coordination units and plenty of hydrogen bonds was designed and incorporated into perovskite films. PDCA units, showing strong intermolecular Pb2+‐Namido, I−‐Npyridyl, and Pb2+‐Oamido coordination interactions, were expected to enhance crystallinity and passivate the grain boundary. In addition, abundant hydrogen bonds in SHP afforded the self‐healing of cracks at grain boundaries for fatigue PSCs. Significantly, the doped device demonstrated a champion efficiency of 19.50 % with inconspicuous hysteresis, almost rivaling those achieved in control atmosphere. This strategy of heterocyclic‐based macromolecular doping in PSCs will pave a way for realizing efficient and durable crystalline semiconductors.

A new type of light-switchable "smart" single-walled carbon nanotube (SWNTs) is developed by the reversible host-guest interaction between azobenzene-terminal PEO (AzoPEO) and pyrene-labeled host attached on the sidewalls of nanotubes via ππ stacking. The SWNTs hybrids not only are well dispersed in pure water, but also exhibit switchable dispersion/aggregation states upon the alternate irradiation of UV and visible light. Moreover, the SWNTs hybrids dispersion is preliminarily used as coating fl uid to form transparent conductive fi lms. The dispersant AzoPEO is removed by the contamination-free UV treatment, decreasing the resistance of the fi lms. This kind of light-switchable SWNTs hybrids, possessing a ''green'' trigger and intact structure of the nanotube, may fi nd potential applications in sensor of biomedicines, device fabrication, etc. Additionally, such a reversible hostguest interaction system may open up the possibility to control the dispersion state of SWNTs by other common polymers. Scheme 1 . The synthesis strategies for a) azobenzene-containing PEO (AzoPEO), and b) pyrene-labelled β -cyclodextrin (p-CD).

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Self-healable siloxane elastomers have recently attracted much interest in research for applications in flexible electronic devices. However, it remains a challenge for self-healable siloxane elastomers to realize good mechanical and rapid high-efficiency selfhealable properties at room temperature. Herein, a desirable siloxane polymer elastomer was designed by the synergy of multiple dynamic bonds. In this self-healable system, the disulfide bonds as sacrificial bonds and hydrogen bonds as weak bonds could endow elastomers with rapid self-healability and high stretchability. Whereas, the Fecoordination bonds could tune the robustness of a siloxane elastomer. Due to the synergy of multiple dynamic bonds, the self-healable PDMS-SS-DOPA1-Fe2 elastomer achieved high stretchability of 1100%, tensile stress of 1.11 MPa, and high self-healable efficiency of 96% (within 3 h). Moreover, after healing for 3 min at room temperature, the damaged siloxane elastomers were able to obtain a breaking strain of 250% and tensile stress of 0.5 MPa. As a proof of concept, based on elastomer films integrated with liquid metal alloy EGaIn (eutectic gallium−indium), stretchable electrodes and strain sensors were subsequently developed, opening the avenue to potential applications in flexible electronics and microsystems.

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Polymer doping is an efficient approach to achieve self-healing perovskite solar cells. However, achieving high self-healing efficiency under moderate conditions remains challenging. Herein, an innovative self-healable polysiloxane (PAT) containing plenty of thiourea hydrogen bonds was designed and introduced into perovskite films. Abundant thiourea hydrogen bonds in PAT facilitated the self-healing of cracks at grain boundaries for damaged SPSCs. Importantly, the doped SPSCs demonstrated a champion efficiency of 19.58% with little hysteresis, almost rivalling those achieved in control atmosphere. Additionally, owing to the effective chelation by PAT and good level of thiourea hydrogen bonds, after 800 cycles of stretching, releasing and self-healing, the doped SPSCs retained 85% of their original IPCE. The self-healing characteristics were demonstrated in situ after stretching at 20% strain for 200 cycles. This strategy of pyridine-based supramolecular doping in SPSCs paves a promising way for achieving efficient and self-healable crystalline semiconductors.