Photovoltaic (PV) cells are the most efficient devices when absorbing photons with energies similar to its bandgap energy. They are therefore incapable of harvesting sub-bandgap photons in the infrared regime and experience significant thermalization losses when absorbing photons in the visible regime with energies above that of the bandgap energy. This excess heat from both regimes has a detrimental effect on the PV cell’s efficiency and lifetime due to the temperature rise. This dilemma has highlighted the need for a photovoltaic device able to utilize the excess heat generated effectively. In this work, an integrated hybrid photo-thermo-voltaic system is presented. The system is comprised of a plasmonic enhanced silicon PV cell with a nanostructure surface to increase the absorption of the visible spectrum. The cell is attached to a heavily doped silicon-based plasmonic infrared super absorber to trap the thermal/infrared portion of the spectrum, facilitating the harvesting of sub-bandgap photons and excess heat from the thermalization losses. The PV and absorber layers of the solar system can be easily fabricated with low cost due to their CMOS compatibility. This harvested heat energy is then utilized to heat the hot side of a connected thermo-electric generator (TEG), which directly convert waste energy into electric power by creating a temperature gradient across the TEG. This TEGs based on traditional semiconductor material 𝐵𝐵𝑖𝑖2𝑇𝑇𝑒𝑒3. Radiation energy near the bandgap is directly transformed to electricity by PV panel and simultaneously, infrared energy is utilized by the TEG to convert heat to electricity. Consequently, more electricity can be produced by the hybrid system than the power produced by a single PV or TE system. The system exhibits a considerable improvement in efficiency and power output when compared to a standalone PV cell or TEG owing to the utilization of the lost heat and IR solar spectrum. Promising applications of the system include energy storage and solar heating.
The thermoelectric effect can be defined as the power that can be ascribed to the results of the temperature gradient
across a junction between two different metals. Micro thermoelectric generators (μTEGs) are used with energies or
losses that have a gradient in temperature or spatial dimensions that are too small for conventional thermodynamic
heat engines to effectively utilize, delivering micro-Watts to milli-Watts of power per device. Silicon nanowires
(SiNW) thermoelectrical properties are more enhanced compared to thin-layer silicon, mainly due to the decrease of
thermal conductivity caused by the quantum confinement and phonon scattering effects in low dimensions. SiNWs as
a thermoelectric material is also very advantageous due to the abundance of silicon as raw material and its ability to
be produced by regular IC manufacturing techniques leading to low cost. Here, our present works show a portable and
autonomous power generation microsystem based on a SiNWs μTEG coupled with an infrared plasmonic absorber for
heat-trapping purposes capable of powering micro/nano system.
One of the major sources of harvesting energy for the μTEGs is the human skin which is presented in our work. The
μTEG is integrated with a micro silicon-based plasmonic IR absorber plate in order to harvest thermal energy in the
IR regime. This enhanced μTEG/absorber hybrid exhibited an increased ability to trap minimum excess heat on its
surface owing to the IR absorber, resulting in a considerable enhancement in output power and conversion efficiency
when compared to a standard μTEG. In this work, full simulations of the absorber are performed in addition to
electrical and thermal simulations for the μTEG by using COMSOL Multiphysics Simulator. The integrated hybrid
microsystem is easily fabricated using standard CMOS processes and has many applications, such as the powering of
wireless sensors and the harvesting of lost heat from electronic components.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.