Highly Selective High‐Speed Circularly Polarized Photodiodes Based on π‐Conjugated Polymers. Issue 2 (2nd November 2021)

• Record Type: Journal Article
• Authors: Ward, Matthew D.; Wade, Jessica; Shi, Xingyuan; Nelson, Jenny; Campbell, Alasdair J.; Fuchter, Matthew J.
• Is Part Of: Advanced optical materials. Volume 10:Issue 2(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-11-02
• Subjects: chiral materials -- chiroptical response -- circularly polarized light -- organic photodiodes -- photodetectors; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202101044
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Chiral π‐conjugated molecular systems that are intrinsically sensitive to the handedness of circularly polarized (CP) light potentially allow for miniaturized, low‐cost CP detection devices. Such devices promise to transform several technologies, including biosensing, quantum optics, and communication of data encrypted by exploiting the spin angular momentum of light. Here a simple, bilayer organic photodiode (CP OPD) comprising an achiral π‐conjugated polymer–chiral additive blend as the electron donor layer and an achiral C60 electron acceptor layer is realized. These devices exhibit considerable photocurrent dissymmetry g ph, with absolute values as high as 0.85 and dark currents as low as 10 pA. Impressively, they showcase a linear dynamic range of 80 dB, and rise and fall times of ≈7 µs, which significantly outperforms all previously reported CP selective photodetectors. Mechanistically, it is shown that the g ph is sensitive to the thickness of both the chiral donor and achiral acceptor layers and that a trade‐off exists between the external quantum efficiency and g ph . The fast‐switching speeds of these devices, coupled with their large dynamic range and highly selective response to CP light, opens up the possibility of their direct application in CP sensing and optical communications. Abstract : Bilayer organic photodiodes sensitive to the handedness of circularly polarized light (CPL) are developed using an achiral π‐conjugated polymer–chiral additive blend donor layer. The influence of device architecture on the selectivity of response to CPL is leveraged to produce optimized devices with considerable photocurrent dissymmetry (up to 0.85), state‐of‐the‐art linear dynamic range (80 dB), and microsecond response times.