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- Title
Flexible high-performance graphene hybrid photodetectors functionalized with gold nanostars and perovskites.
- Authors
Lee, Yoon Ho; Park, Seungyoung; Won, Yousang; Mun, Jungho; Ha, Jae Hwan; Lee, Jeong Hun; Lee, Sang Hyuk; Park, Jongmin; Yeom, Jeonghee; Rho, Junsuk; Ko, Hyunhyub; Oh, Joon Hak
- Abstract
Hybrid materials in optoelectronic devices can provide synergistic effects that complementarily enhance the properties of each component. Here, flexible high-performance graphene hybrid photodetectors (PDs) are developed by introducing gold nanostars (GNSs) and perovskites for strong light trapping with hot electron transfer and efficient light harvesting characteristics, respectively. While pristine graphene PDs do not exhibit discernible photodetection properties due to the very low photon absorption and ultrafast charge carrier recombination, graphene PDs functionalized with GNSs and a densely covered perovskite layer exhibit outstanding photoresponsive properties with a photoresponsivity (R) of 5.90 × 104 A W−1 and a specific detectivity of 1.31 × 1013 Jones, the highest values among those reported for perovskite-functionalized graphene PDs thus far. Moreover, we fabricated a flexible 10 × 10 PD array that shows well-resolved spatiotemporal mapping of light signals with excellent operational and mechanical stabilities at a bending radius down to 3 mm and in repeated bending tests for over 1000 cycles. Comprehensive analyses using finite-difference time-domain (FDTD) theoretical calculations, scanning near-field optical microscopy, and photoluminescence mapping reveal the effective light trapping effect of GNSs and the charge carrier transfer between the perovskite and graphene. This work provides a new design platform for flexible and high-performance photodetection systems. Optical sensors: graphene gets a gold star for performance Flexible photodetectors that convert light into electric signals for applications including low-light photography can be improved using star-shaped flecks of gold. Single-atom thin graphene sheets have proven useful in many bendable photodetectors due to their favorable mechanical and electronic properties. South Korean researchers led by Hyunhyub Ko from the Ulsan National Institute of Science and Technology and Joon Hak Oh at Seoul National University have now developed a technique to improve graphene's response to light. By tweaking a typical nanoparticle synthesis method using a sulfur-based buffering agent, the team produced gold nanostars that trap light using localized field-enhanced regions around their spiky tips. Prototype devices, prepared by putting nanostar-coated graphene electrodes onto plastic substrates, could be flexed thousands of times while retaining sufficient light sensitivity for imaging purposes. Flexible high-performance hybrid graphene photodetectors have been developed by introducing both perovskite materials and gold nanostars. The developed photodetectors exhibit significantly enhanced optoelectronic performances due to the synergistic effects of hybrid system including high light absorption of perovskites and strong plasmonic effects of gold nanostars with high mechanical stability, which extends the range of their practical applications.
- Subjects
SOUL Taehakkyo; OPTOELECTRONIC devices; CHARGE carriers; NEAR-field microscopy; PEROVSKITE; GRAPHENE; PHOTODETECTORS; HYBRID systems; NANOPARTICLE synthesis
- Publication
NPG Asia Materials, 2020, Vol 12, Issue 1, p1
- ISSN
1884-4049
- Publication type
Article
- DOI
10.1038/s41427-020-00260-1