Fractal Web Design of a Hemispherical Photodetector Array with Organic‐Dye‐Sensitized Graphene Hybrid Composites. Issue 46 (12th October 2020)

• Record Type: Journal Article
• Authors: Lee, Eun Kwang; Baruah, Ratul Kumar; Leem, Jung Woo; Park, Woohyun; Kim, Bong Hoon; Urbas, Augustine; Ku, Zahyun; Kim, Young L.; Alam, Muhammad Ashraful; Lee, Chi Hwan
• Is Part Of: Advanced materials. Volume 32:Issue 46(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-12
• Subjects: compound‐eye imaging systems -- fractal web design -- hemispherical photodetector arrays -- organic dye‐sensitized graphene -- wet‐transfer printing; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202004456
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: The vision system of arthropods consists of a dense array of individual photodetecting elements across a curvilinear surface. This compound‐eye architecture could be a useful model for optoelectronic sensing devices that require a large field of view and high sensitivity to motion. Strategies that aim to mimic the compound‐eye architecture involve integrating photodetector pixels with a curved microlens, but their fabrication on a curvilinear surface is challenged by the use of standard microfabrication processes that are traditionally designed for planar, rigid substrates (e.g., Si wafers). Here, a fractal web design of a hemispherical photodetector array that contains an organic‐dye‐sensitized graphene hybrid composite is reported to serve as an effective photoactive component with enhanced light‐absorbing capabilities. The device is first fabricated on a planar Si wafer at the microscale and then transferred to transparent hemispherical domes with different curvatures in a deterministic manner. The unique structural property of the fractal web design provides protection of the device from damage by effectively tolerating various external loads. Comprehensive experimental and computational studies reveal the essential design features and optoelectronic properties of the device, followed by the evaluation of its utility in the measurement of both the direction and intensity of incident light. Abstract : A spider‐web‐inspired fractal design is integrated with a high‐performance photodetector array, providing a viable possibility for hemispherical light detection to replicate the vision system of arthropods such as insects and crustaceans. The enhanced photoresponsivity (>1000 A W −1 ) and mechanical reliability of the hemisherical photodetector are enabled by the use of organic‐dye‐sensitized graphene hybrid composites.