Silicon nitride grating based planar spectral splitting concentrator for NIR light Harvesting

TL;DR

This paper presents a multi-layered silicon nitride grating-based planar concentrator that efficiently splits and guides NIR sunlight for improved photovoltaic energy harvesting, achieving notable efficiency levels.

Contribution

It introduces a novel multi-layered spectral splitting concentrator using silicon nitride gratings optimized for NIR light, enhancing solar energy harvesting capabilities.

Findings

NIR guiding efficiency of ~18%

Power conversion efficiency of ~11%

Potential for building integrated photovoltaics

Abstract

We design a multi-layered solar spectral splitting planar concentrator for near infrared (NIR) light energy harvesting application. Each layer includes a silicon nitride based subwavelength diffraction grating on top of a glass substrate that is optimized to diffract the incoming solar radiation in a specific band from a broad spectral band (700-1400 nm in the NIR region) into guided modes propagating inside the glass substrate. The steep diffraction angle due to subwavelength grating results in concentrated light at the edge of each layer where it is then converted to electricity using a photovoltaic cell. The spectral splitting planar concentrator shows an overall NIR guiding efficiency of ~18%, and power conversion efficiency of ~11%. The design can be potentially used for building integrated photovoltaics application.