Lithography-Free Broadband Ultrathin-Film Absorbers with Gap-Plasmon Resonance for Organic Photovoltaics

Minjung Choi, Gumin Kang, Dongheok Shin, Nilesh Barange, Chang Won Lee, Doo Hyun Ko, Kyoungsik Kim

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Strategies to confine electromagnetic field within ultrathin film emerge as essential technologies for applications from thin-film solar cells to imaging and sensing devices. We demonstrate a lithography-free, low-cost, large-scale method to realize broadband ultrathi-film metal-dielectric-metal (MDM) absorbers, by exploiting gap-plasmon resonances for strongly confined electromagnetic field. A two-steps method, first organizing Au nanoparticles via thermal dewetting and then transferring the nanoparticles to a spacer-reflector substrate, is used to achieve broader absorption bandwidth by manipulating geometric shapes of the top metallic layer into hemiellipsoids. A fast-deposited nominal Au film, instead of a conventional slow one, is employed in the Ostwald ripening process to attain hemiellipsoidal nanoparticles. A polymer supported transferring step allows a wider range of dewetting temperature to manipulate the nanoparticles' shape. By incorporating circularity with ImageJ software, the geometries of hemiellipsoidal nanoparticles are quantitatively characterized. Controlling the top geometry of MDM structure from hemisphere to hemiellipsoid increases the average absorption at 500-900 nm from 23.1% to 43.5% in the ultrathin film and full width at half-maximum of 132-324 nm, which is consistently explained by finite-difference time-domain simulation. The structural advantages of our scheme are easily applicable to thin-film photovoltaic devices because metal electrodes can act as metal reflectors and semiconductor layers as dielectric spacers.

Original languageEnglish
Pages (from-to)12997-13008
Number of pages12
JournalACS Applied Materials and Interfaces
Volume8
Issue number20
DOIs
Publication statusPublished - 2016 May 25

Fingerprint

Ultrathin films
Lithography
Metals
Nanoparticles
Electromagnetic fields
Ostwald ripening
Geometry
Full width at half maximum
Polymers
Semiconductor materials
Bandwidth
Imaging techniques
Thin films
Electrodes
Substrates
Costs

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Cite this

Choi, Minjung ; Kang, Gumin ; Shin, Dongheok ; Barange, Nilesh ; Lee, Chang Won ; Ko, Doo Hyun ; Kim, Kyoungsik. / Lithography-Free Broadband Ultrathin-Film Absorbers with Gap-Plasmon Resonance for Organic Photovoltaics. In: ACS Applied Materials and Interfaces. 2016 ; Vol. 8, No. 20. pp. 12997-13008.
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Lithography-Free Broadband Ultrathin-Film Absorbers with Gap-Plasmon Resonance for Organic Photovoltaics. / Choi, Minjung; Kang, Gumin; Shin, Dongheok; Barange, Nilesh; Lee, Chang Won; Ko, Doo Hyun; Kim, Kyoungsik.

In: ACS Applied Materials and Interfaces, Vol. 8, No. 20, 25.05.2016, p. 12997-13008.

Research output: Contribution to journalArticle

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