Although its importance is often underappreciated, light plays a crucial role in modern electronics: Photovoltaic and photodetector systems are integral to the function of a wide array of devices, from cameras and monitors to solar cells and medical equipment. And like many other phenomena, the interaction of light with material structures is altered in the nanoscale, and these changes can be used to create more effective light-sensing and transmitting devices – a dire necessity in the increasingly compact world of electronics. Nanowires in particular have been popular for light-based applications at the nanoscale, since their optical properties can be tuned with ease through modifications to their length, thickness or composition – although their small cross-sections and overall volumes do not endear them to the would-be device designer, as these properties severely undercut their absorption capacities.
But a new configuration, proposed by Dr. Tural Khudiyev and Professor Mehmet Bayındır from Nanomaterials and Nanophotonics Laboratory at UNAM, now gives nanowires the light-absorbing properties they require, potentially allowing the design of new nanoscale photovoltaic systems. The authors’ system consists of two nanowires (one for absorbing incident light and one for enhancing the function of the absorber) that contact the surface through metal “supports”, which allows non-resonant Mie scattering to occur and increases absorption efficiency by “bouncing” light within the material. This configuration also allows the device to benefit from the intrinsic properties of non-resonant Mie scattering, including broadband enhancement, large-area absorption capacity, polarization independency, forward scattering and a distinctive coupling behavior that facilitates the efficient trapping of light by the material. The combination of these characteristics ultimately leads to a 15-fold increase in absorption efficiency and a 400-fold reduction in material requirements, which are largely independent of the material type or nanowire size used.
The authors believe that their new nanomaterial architecture may allow the liberal use of effective but highly expensive materials in the production of optoelectronic devices, and especially in the design of nanoscale solar cells. This work supported by ERC-European Research Council. The article has been published in the journal Scientific Reports and can be accessed at the following address: