Skip to main content

Optoelectronic sensing of biophysical and biochemical signals based on photon recycling of a micro-LED


Conventional bioelectrical sensors and systems integrate multiple power harvesting, signal amplification and data transmission components for wireless biological signal detection. This paper reports the real-time biophysical and biochemical activities can be optically captured using a microscale light-emitting diode (micro-LED), eliminating the need for complicated sensing circuit. Such a thin-film diode based device simultaneously absorbs and emits photons, enabling wireless power harvesting and signal transmission. Additionally, owing to its strong photon-recycling effects, the micro-LED’s photoluminescence (PL) emission exhibits a superlinear dependence on the external conductance. Taking advantage of these unique mechanisms, instantaneous biophysical signals including galvanic skin response, pressure and temperature, and biochemical signals like ascorbic acid concentration, can be optically monitored, and it demonstrates that such an optoelectronic sensing technique outperforms a traditional tethered, electrically based sensing circuit, in terms of its footprint, accuracy and sensitivity. This presented optoelectronic sensing approach could establish promising routes to advanced biological sensors.


  1. [1]

    Kim, D. H.; Lu, N. S.; Ma, R.; Kim, Y. S.; Kim, R. H.; Wang, S. D.; Wu, J.; Won, S. M.; Tao, H.; Islam, A. et al. Epidermal electronics. Science 2011, 333, 838–843.

    CAS  Article  Google Scholar 

  2. [2]

    Gao, W.; Emaminejad, S.; Nyein, H. Y. Y.; Challa, S.; Chen, K.; Peck, A.; Fahad, H. M.; Ota, H.; Shiraki, H.; Kiriya, D. et al. Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis. Nature 2016, 529, 509–514.

    CAS  Article  Google Scholar 

  3. [3]

    Imani, S.; Bandodkar, A. J.; Mohan, A. M. V.; Kumar, R.; Yu, S. F.; Wang, J.; Mercier, P. P. A wearable chemical-electrophysiological hybrid biosensing system for real-time health and fitness monitoring. Nat. Commun. 2016, 7, 11650.

    CAS  Article  Google Scholar 

  4. [4]

    Kim, J.; Campbell, A. S.; de Ávila, B. E. F.; Wang, J. Wearable biosensors for healthcare monitoring. Nat. Biotechnol. 2019, 37, 389–406.

    CAS  Article  Google Scholar 

  5. [5]

    Chung, H. U.; Kim, B. H.; Lee, J. Y.; Lee, J.; Xie, Z. Q.; Ibler, E. M.; Lee, K.; Banks, A.; Jeong, J. Y.; Kim, J. et al. Binodal, wireless epidermal electronic systems with in-sensor analytics for neonatal intensive care. Science 2019, 363, eaau0780.

    CAS  Article  Google Scholar 

  6. [6]

    Reynolds, M. F.; Guimarães, M. H. D.; Gao, H.; Kang, K.; Cortese, A. J.; Ralph, D. C.; Park, J.; McEuen, P. L. MoS2 pixel arrays for real-time photoluminescence imaging of redox molecules. Sci. Adv. 2019, 5, eaat9476.

    CAS  Article  Google Scholar 

  7. [7]

    Piech, D. K.; Johnson, B. C.; Shen, K.; Ghanbari, M. M.; Li, K. Y.; Neely, R. M.; Kay, J. E.; Carmena, J. M.; Maharbiz, M. M.; Muller, R. A wireless millimetre-scale implantable neural stimulator with ultrasonically powered bidirectional communication. Nat. Biomed. Eng. 2020, 4, 207–222.

    Article  Google Scholar 

  8. [8]

    Bariya, M.; Nyein, H. Y. Y.; Javey, A. Wearable sweat sensors. Nat. Electron. 2018, 1, 160–171.

    Article  Google Scholar 

  9. [9]

    Cortese, A. J.; Smart, C. L.; Wang, T. Y.; Reynolds, M. F.; Norris, S. L.; Ji, Y. X.; Lee, S.; Mok, A.; Wu, C. Y.; Xia, F. et al. Microscopic sensors using optical wireless integrated circuits. Proc. Natl. Acad. Sci. USA 2020, 117, 9173–9179.

    CAS  Article  Google Scholar 

  10. [10]

    Lou, Z.; Wang, L. L.; Jiang, K.; Wei, Z. M.; Shen, G. Z. Reviews of wearable healthcare systems: Materials, devices and system integration. Mater. Sci. Eng. R Rep. 2020, 140, 100523.

    Article  Google Scholar 

  11. [11]

    Neamen, D. A. Semiconductor Physics and Devices, 3rd ed.; McGraw-Hill: Boston, 2003.

    Google Scholar 

  12. [12]

    Ding, H.; Hong, H.; Cheng, D. L.; Shi, Z.; Liu, K. H.; Sheng, X. Power- and spectral-dependent photon-recycling effects in a double-junction gallium arsenide photodiode. ACS Photonics 2019, 6, 59–65.

    CAS  Article  Google Scholar 

  13. [13]

    Sheng, X.; Yun, M. H.; Zhang, C.; Al-Okaily, A. M.; Masouraki, M.; Shen, L.; Wang, S. D.; Wilson, W. L.; Kim, J. Y.; Ferreira, P. et al. Device architectures for enhanced photon recycling in thin-film multijunction solar cells. Adv. Energy Mater. 2015, 5, 1400919.

    Article  Google Scholar 

  14. [14]

    Peng, M. Z.; Li, Z.; Liu, C. H.; Zheng, Q.; Shi, X. Q.; Song, M.; Zhang, Y.; Du, S. Y.; Zhai, J. Y.; Wang, Z. L. High-resolution dynamic pressure sensor array based on piezo-phototronic effect tuned photoluminescence imaging. ACS Nano 2015, 9, 3143–3150.

    CAS  Article  Google Scholar 

  15. [15]

    Stolterfoht, M.; Le Corre, V. M.; Feuerstein, M.; Caprioglio, P.; Koster, L. J. A.; Neher, D. Voltage-dependent photoluminescence and how it correlates with the fill factor and open-circuit voltage in perovskite solar cells. ACS Energy Lett. 2019, 4, 2887–2892.

    CAS  Article  Google Scholar 

  16. [16]

    Macka, M.; Piasecki, T.; Dasgupta, P. K. Light-emitting diodes for analytical chemistry. Annu. Rev. Anal. Chem. 2014, 7, 183–207.

    CAS  Article  Google Scholar 

  17. [17]

    Ding, H.; Lu, L. H.; Shi, Z.; Wang, D.; Li, L. Z.; Li, X. C.; Ren, Y. Q.; Liu, C. B.; Cheng, D. L.; Kim, H. et al. Microscale optoelectronic infrared-to-visible upconversion devices and their use as injectable light sources. Proc. Natl. Acad. Sci. USA 2018, 115, 6632–6637.

    CAS  Article  Google Scholar 

  18. [18]

    Marti, A.; Balenzategui, J. L.; Reyna, R. F. Photon recycling and shockley’s diode equation. J. Appl. Phys. 1997, 82, 4067–4075.

    CAS  Article  Google Scholar 

  19. [19]

    Miller, O. D.; Yablonovitch, E.; Kurtz, S. R. Strong internal and external luminescence as solar cells approach the Shockley-Queisser limit. IEEE J. Photovolt. 2012, 2, 303–311.

    Article  Google Scholar 

  20. [20]

    Tex, D. M.; Imaizumi, M.; Akiyama, H.; Kanemitsu, Y. Internal luminescence efficiencies in InGaP/GaAs/Ge triple-junction solar cells evaluated from photoluminescence through optical coupling between subcells. Sci. Rep. 2016, 6, 38297.

    CAS  Article  Google Scholar 

  21. [21]

    Su, Z. C.; Xu, S. J.; Wang, X. H.; Ning, J. Q.; Wang, R. X.; Lu, S. L.; Dong, J. R.; Yang, H. Effective photon recycling and super long lived minority carriers in GaInP/GaAs heterostructure solar cell: A time-resolved optical study. IEEE J. Photovolt. 2018, 8, 820–824.

    Article  Google Scholar 

  22. [22]

    Richter, C. P. Physiological factors involved in the electrical resistance of the skin. Am. J. Physiol-Legacy Content 1929, 88, 596–615.

    Article  Google Scholar 

  23. [23]

    Boucsein, W. Electrodermal Activity, 2nd ed.; Springer: New York, 2012.

    Book  Google Scholar 

  24. [24]

    Sliney, D. H.; Wolbarsht, M. Safety with Lasers and other Optical Sources: A Comprehensive Handbook; Springer: New York, 1980.

    Book  Google Scholar 

  25. [25]

    Frijda, N. H. The Emotions; Cambridge University Press: Cambridge, 1986.

    Google Scholar 

  26. [26]

    Yang, Y. B.; Yang, X. D.; Tan, Y. N.; Yuan, Q. Recent progress in flexible and wearable bio-electronics based on nanomaterials. Nano Res. 2017, 10, 1560–1583.

    Article  Google Scholar 

  27. [27]

    Zhang, F. J.; Zang, Y. P.; Huang, D. Z.; Di, C. A.; Zhu, D. B. Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials. Nat. Commun. 2015, 6, 8356.

    CAS  Article  Google Scholar 

  28. [28]

    Rogalski, A. Infrared detectors: An overview. Infrared Phys. Technol. 2002, 43, 187–210.

    Article  Google Scholar 

  29. [29]

    Emaminejad, S.; Gao, W.; Wu, E.; Davies, Z. A.; Yin Yin Nyein, H.; Challa, S.; Ryan, S. P.; Fahad, H. M.; Chen, K.; Shahpar, Z. et al. Autonomous sweat extraction and analysis applied to cystic fibrosis and glucose monitoring using a fully integrated wearable platform. Proc. Natl. Acad. Sci. USA 2017, 114, 4625–4630.

    CAS  Article  Google Scholar 

  30. [30]

    Liu, C. B.; Zhao, Y.; Cai, X.; Xie, Y.; Wang, T. Y.; Cheng, D. L.; Li, L. Z.; Li, R. F.; Deng, Y. P.; Ding, H. et al. A wireless, implantable optoelectrochemical probe for optogenetic stimulation and dopamine detection. Microsyst. Nanoeng. 2020, 6, 64.

    CAS  Article  Google Scholar 

  31. [31]

    Levine, M.; Conry-Cantilena, C.; Wang, Y.; Welch, R. W.; Washko, P. W.; Dhariwal, K. R.; Park, J. B.; Lazarev, A.; Graumlich, J. F.; King, J. et al. Vitamin C pharmacokinetics in healthy volunteers: Evidence for a recommended dietary allowance. Proc. Natl. Acad. Sci. USA 1996, 93, 3704–3709.

    CAS  Article  Google Scholar 

  32. [32]

    Zhang, X.; Cao, Y.; Yu, S.; Yang, F. C.; Xi, P. X. An electrochemical biosensor for ascorbic acid based on carbon-supported PDN inanoparticles. Biosens. Bioelectron. 2013, 44, 183–190.

    Article  Google Scholar 

  33. [33]

    Dhara, K.; Debiprosad, R. M. Review on nanomaterials-enabled electrochemical sensors for ascorbic acid detection. Anal. Biochem. 2019, 586, 113415.

    CAS  Article  Google Scholar 

  34. [34]

    Bernstein, R. E. Excretion of vitamin C in sweat. Nature 1937, 140, 684–685.

    CAS  Article  Google Scholar 

  35. [35]

    Wang, Y. C.; Zhu, H. L.; Yang, H. R.; Argall, A. D.; Luan, L.; Xie, C.; Guo, L. Nano functional neural interfaces. Nano Res. 2018, 11, 5065–5106.

    Article  Google Scholar 

Download references


Funding: the National Natural Science Foundation of China (NSFC) (No. 61874064); Beijing Institute of Technology Research Fund Program for Young Scholars; Beijing Innovation Center for Future Chips, Tsinghua University; Beijing National Research Center for Information Science and Technology (No. BNR2019ZS01005). The authors acknowledge characterization work supported by Beijing Institute of Technology Analysis & Testing Center. We also thank Nianzhen Du for the image design.

Author information



Corresponding author

Correspondence to Xing Sheng.

Electronic Supplementary Material

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Ding, H., Lv, G., Shi, Z. et al. Optoelectronic sensing of biophysical and biochemical signals based on photon recycling of a micro-LED. Nano Res. 14, 3208–3213 (2021).

Download citation


  • photon recycling
  • photoluminescence
  • microscale light-emitting diodes (micro-LEDs)
  • optoelectronics
  • biosensors