www.afm-journal.de © 2020 Wiley-VCH GmbH 2005727 (1 of 7) FULL PAPER Integration and Synergy of Organic Single Crystals and Metal–Organic Frameworks in Core–Shell Heterostructures Enables Outstanding Gas Selectivity for Detection Jianzhong Zheng, Kanglei Pang, Xu Liu, Shunxing Li,* Rui Song,* Yaling Liu,* and Zhiyong Tang Controllable integration of two or more functional components is one of the most convenient and efective ways to obtain composite advanced materials with collective properties and improved performance. In this work, in combination with organic single crystals and metal–organic frameworks (MOFs), a novel 1D well-defned core–shell heterostructure with single copper phthalocyanine (CuPc) ribbon cores coated with a uniform isoreticular MOF-3 (IRMOF-3) shell is successfully constructed. Impressively, thanks to performance the integration and synergy of the CuPc cores and the IRMOF-3 shells, the sensor devices based on such single heterostructures exhibit outstanding selectivity for NH 3 detection at ≈60% relative humidity at room temperature, the current response of which to NH 3 is around 34–265 times the magnitude of response to ten potential interfering gases even in the case of the 1:100 concentration ratio of NH 3 (5 ppm) and the interfering gases (500 ppm). Moreover, the detection limit of such CuPc@IRMOF-3 sensors toward NH 3 is estimated to be 52 ppb (signal to noise ratio = 3) based on 11 blank determinations, and good stability and reusability can also be achieved. This work highlights that the integration of organic single crystals and MOFs into well-defned structures ofers a new opportunity for high- performance gas sensors. DOI: 10.1002/adfm.202005727 Dr. J. Z. Zheng, K. L. Pang, Dr. X. Liu, Prof. Y. L. Liu, Prof. Z. Y. Tang CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology No.11, Beiyitiao, Zhongguancun, Beijing 100190, P. R. China E-mail: liuyl@nanoctr.cn Dr. J. Z. Zheng, Prof. S. X. Li Fujian Provincial Key Laboratory of Pollution Monitoring and Control Minnan Normal University Zhangzhou, Fujian 363000, P. R. China E-mail: lishunxing@mnnu.edu.cn K. L. Pang, Prof. R. Song, Prof. Y. L. Liu, Prof. Z. Y. Tang University of Chinese Academy of Sciences No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, P. R. China E-mail: rsong@ucas.ac.cn The ORCID identifcation number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.202005727. been a priority area of high concern to human health, which promotes tremen- dous advances in sensing technology. Among the developed sensor technolo- gies, chemical sensors have become one of the most efective platforms for prac- tical monitoring and detection of toxic gases such as ammonia (NH 3 ). [1] However, owing to the limitations of the sensor type, the performance of the sensing materials, the signal processing, etc., almost all the currently developed gas sensors have their own defciencies hindering their further potential application. [2] Among them, low selectivity, one of the major drawbacks of most gas sensors, is of particular concern and has always been the most important challenge for current generation detection and monitoring devices especially toward detecting a specifc gas when mixed with other interfering gases. [3] It is known that selectivity is closely related to the perfor- mance of the sensing materials, especially the ability to capture analytes. [3b] Hence, it is still urgent to develop novel sensing materials with excellent selectivity to analytes combining with high sensitivity, high sta- bility, low power consumption, etc. so as to meet various testing requirements. Controllable integration of two or more functional compo- nents has been confrmed to be one of the most convenient and efective ways to obtain composite advanced materials with collective properties and improved performance. [4] Inspired by this, we suggest adopting the well-defned core–shell het- erostructures as the sensing materials via a combination of 1D conducting polymer single crystals and metal–organic frame- works (MOFs). On the one hand, conducting polymers such as phthalocyanines (Pcs), polyanilines, and their derivatives are one of the most promising gas sensing materials with changes in conductivity property upon interaction with gases at room temperature; [5] and moreover, 1D single-crystalline structure is more benefcial to lead to exceptional device performance, reduced device size and low power consumption owing to the high surface-to-volume ratio, few undesirable grain boundaries and low density of defects. [6] On the other hand, MOFs have sig- nifcant advantages in selectively capturing gas analytes owing to their special structural characteristics including chemical 1. Introduction Efcient trace detection and monitoring of environmental pollutants, especially the harmful and toxic gases, has always Adv. Funct. Mater. 2020, 2005727