An Organic Chiroptical Detector Favoring Circularly Polarized Light Detection from Near‐Infrared to Ultraviolet and Magnetic‐Field‐Amplifying Dissymmetry in Detectivity

RESEARCH ARTICLE www.advmat.de An Organic Chiroptical Detector Favoring Circularly Polarized Light Detection from Near-Infrared to Ultraviolet and Magnetic-Field-Amplifying Dissymmetry in Detectivity Renjie Hu, Xiangqian Lu, Xiaotao Hao, and Wei Qin* Circularly polarized light detection has attracted growing attention because of its unique application in security surveillance and quantum optics. Here, through designing a chiral polymer as a donor, a high-performance circularly polarized light detector is fabricated, successfully enabling detection from ultraviolet (300 nm) to near-infrared (1100 nm). The chiroptical detector presents an excellent ability to distinguish right-handed and left-handed circularly polarized light, where dissymmetries in detectivity, responsivity, and electric current are obtained and then optimized. The dissymmetry in electric current can be increased from 0.18 to 0.23 once an external magnetic field is applied. This is a very rare report on the dissymmetry tunability by an external field in chiroptical detectors. Moreover, the chirality-generated orbital angular momentum is one of the key factors determining the performance of the circularly polarized light detection. Overall, the organic chiroptical detector presents excellent stability in detection, which provides great potential for future flexible and compact integrated platforms. 1. Introduction Different from linearly polarized light, circularly polarized light (CPL)-carried photons are of function for encryption, which presents great applications in optical communication,[1] bio- logical detection,[2] etc. Correspondingly, the detection of CPL has become important. Recent years, based on diodes,[3] field- effect transistors and other types of structures to fabricate CPL detectors,[4] the detection of CPL has been advancing. The param- eters of some organic detectors have been optimized to overcome the challenge in stability. Yet, the employment of CPL-based com- munication and detection requires the availability of high-fidelity R. Hu, X. Lu, X. Hao, W. Qin School of Physics State Key Laboratory of Crystal Materials Shandong University Jinan 250100, China E-mail: wqin@sdu.edu.cn X. Hao ARC Centre of Excellence in Exciton Science School of Chemistry The University of Melbourne Parkville, Victoria 3010, Australia The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202211935 DOI: 10.1002/adma.202211935 CPL selective detectors to fulfill the require- ment of miniaturization and integration.[5] To overcome the issues, in recent years, chi- ral materials have been designed and ap- plied because of their intrinsic properties to distinguish the left- and right-handed circu- larly polarized (LCP and RCP) light.[6] For the design of chiral materials, a variety of methods including electro- chemical preparation,[7] photochemical preparation,[8] and solvent induction.[6a,9] have been used to generate chiral struc- ture. Utilizing chiral materials of 1D,[10] 2D,[11] and 3D structures to fabricate detectors,[3a,4c,12] a high detectivity of CPL can be obtained.[3a,13] Besides, CPL detec- tion dependence of chiral materials with flexibility and fruitful derivatives can pro- vide a well platform for the improvement of CPL detection. For example, chiral ProSQ-C6 blended with a conventional fullerene acceptor, opti- cal dissymmetry translates into a photocurrent dissymmetry gen- erating a maximum dissymmetry factor of 0.1.[14] Also, chiral donors of DPP6T chromophore modified with (S)- or (R)-2,6- dimethyloctane to fabricate bulk heterojunction devices, where dissymmetry factor can reach as high as 0.17.[15] To further in- crease the magnitude of dissymmetry factor for CPL detection, organic materials with higher mobility is used to prevent the re- laxation of dissymmetry signal as much as possible.[16] Mean- while, a pair of enantiomers NTPH-P(P,P,P) (1-P) and NTPH- P(M,M,M) (1-M) were used to fabricate bi