Artificial phototropism for omnidirectional tracking and harvesting of light

Xiaoshi Qian, Yusen Zhao, Yousif Alsaid, Xu Wang, Mutian Hua, Tiphaine Galy, Hamsini Gopalakrishna, Yunyun Yang, Jinsong Cui, Ning Liu, Michal Marszewski, Laurent Pilon, Hanqing Jiang, Ximin He

Research output: Contribution to journalArticlepeer-review

166 Scopus citations


Many living organisms track light sources and halt their movement when alignment is achieved. This phenomenon, known as phototropism, occurs, for example, when plants self-orient to face the sun throughout the day. Although many artificial smart materials exhibit non-directional, nastic behaviour in response to an external stimulus, no synthetic material can intrinsically detect and accurately track the direction of the stimulus, that is, exhibit tropistic behaviour. Here we report an artificial phototropic system based on nanostructured stimuli-responsive polymers that can aim and align to the incident light direction in the three-dimensions over a broad temperature range. Such adaptive reconfiguration is realized through a built-in feedback loop rooted in the photothermal and mechanical properties of the material. This system is termed a sunflower-like biomimetic omnidirectional tracker (SunBOT). We show that an array of SunBOTs can, in principle, be used in solar vapour generation devices, as it achieves up to a 400% solar energy-harvesting enhancement over non-tropistic materials at oblique illumination angles. The principle behind our SunBOTs is universal and can be extended to many responsive materials and a broad range of stimuli.

Original languageEnglish (US)
Pages (from-to)1048-1055
Number of pages8
JournalNature nanotechnology
Issue number11
StatePublished - Nov 1 2019

ASJC Scopus subject areas

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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