This study characterizes a hybrid structure formed between graphene and organic dye molecules for use in photodetectors with spectral color selectivity. Rhodamine-based organic dye molecules with red, green, or blue light absorption profiles are deposited onto a graphene surface by dip-coating. UV–vis absorption spectroscopy, charge transport measurements, and density functional theory based calculations reveal that the photoresponses of the dye graphene hybrid films are governed by the light absorption of the dye molecules and also by the photo-excited-charge-transfer-induced photocurrent gain. The hybrid films respond only to photons with an energy exceeding the band gap of the immobilized dye. Dye-Graphene charge transfer is affected by the distance and direction of the dipole moment between the two layers. The resulting hybrid films exhibit spectral color selectivities with responsivities of ≈103 A W−1 and specific detectivities of ≈1010 Jones. This study demonstrates the successful operation of photodetectors with a full-color optical bandwidth using hybrid graphene structures coated with a mixture of dyes. The strategy of building a simple hybrid photodetector can further offer many opportunities to be also tuned for other optical functionalities using a variety of commercially available dye molecules.
Bibliographical noteFunding Information:
Y.S.G. and Y.L. contributed equally to this work. S. K., S. H., and C. W. conducted DFT calculations. This work was supported by Samsung Research Funding Center of Samsung Electronics under Project Number SRFCMA1402-00. S. K. was supported by Northwestern Argonne Institute of Science and Engineering (NAISE). S. H. and C. W. acknowledge financial support from the U.S. Department of Energy under Grant No. DE-FG02-07ER46433. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. S. K. is grateful for fruitful discussions with Muratahan Aykol.
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics