Broadband and Omnidirectional Antireflection Surfaces Based on Deep Subwavelength Features for Harvesting of the Solar Energy

Ashish Prajapati, Jordi Llobet, Patrícia C. Sousa, Helder Fonseca, Carlos Calaza, Gil Shalev

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Broadband and omnidirectional antireflective surfaces are important to various solar energy technologies. The utilization of deep subwavelength features is reported for decrement in the broadband and omnidirectional reflection of the solar spectrum. The study commences with nanopillar (NP) arrays that are well known for their antireflection properties. Deep subwavelength features to the nanopillar arrays are introduced, which yield further decrease in reflection: quasinanolens (qNL), deep subwavelength sidewall scalloping (DSSS), and decreasing the nanopillar bottom diameter to reshape it into a light funnel (LF). Accordingly, surface silicon arrays are realized in a top−down fabrication process: nanopillar arrays, nanopillar arrays incorporated with DSSS, nanopillar arrays incorporated with qNL, nanopillar arrays incorporated with qNL and DSSS, and nanopillar arrays that are transformed into LF arrays and are complemented with qNL and DSSS. It is experimentally shown that utilization of deep subwavelength features produces a broadband reflection decrement with an almost 80% decrement for normal incidence and 60% decrement for an angle of incidence of 80°, for unpolarized illumination. The introduction of deep subwavelength features concludes a 20% decrement in the broadband diffused reflection compared with undecorated NP arrays. The effect of deep subwavelength features is also explored numerically, and the possible underlying light-trapping mechanisms are discussed.

Original languageEnglish
Article number2100548
JournalSolar RRL
Issue number12
StatePublished - 1 Dec 2021


  • angle-of-incidence
  • broadband omnidirectional anti-reflection
  • light funnels
  • light trapping
  • nanopillar arrays
  • photon management
  • solar energy harvesting

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


Dive into the research topics of 'Broadband and Omnidirectional Antireflection Surfaces Based on Deep Subwavelength Features for Harvesting of the Solar Energy'. Together they form a unique fingerprint.

Cite this