Tania Roy

Abstract

Researchers at the University of Central Florida have developed a novel architecture and process for producing low-cost, ultrathin, flexible and durable solar cells that can be easily fabricated using roll-to-roll processing. UCF's new light trapping scheme uses nanoparticles to mimic the essential light trapping mechanisms found in a leaf: focusing, wave guiding and light scattering. Unlike conventional solar cell architectures, the invention incorporates the use of lightweight, pliable 2D semiconductor materials and an all-dielectric approach which is lossless in the visible spectrum of light. It also offers broadband polarization-independent reflection features, so that solar cells can capture sunlight from almost any angle.

Technical Details

The invention is a biomimetic light trapping scheme that can be applied to create ultrathin, lightweight, flexible and durable Schottky junction, P-N junction, or any other type of solar cells. By using two optically tuned layers, the light trapping scheme does not employ any nano-structuring of the active silicon substrate, thereby ensuring that the optical gain is not offset due to recombination losses. As well, complete decoupling of the optical and electrical systems enables independent optimization of the light trapping scheme. The scheme accommodates the use of a variety of materials for the two optical layers, with the ratio of the nanoparticle diameters playing a crucial role in achieving light trapping that is omnidirectional, polarization-independent, and more pronounced in the high wavelength regime.

Benefit

Market Application

Publications

A leaf-inspired photon management scheme using optically tuned bilayer nanoparticles for ultra-thin and highly efficient photovoltaic devices,  Nano Energy, Volume 58, April 2019, Pages 47-56

Abstract

Researchers at the University of Central Florida have developed a phototransistor device that can act as an artificial photonic synapse for neuromorphic computing. Ultrathin and highly efficient, the device comprises a superstructure with the fast charge transport capability of graphene (G) and the efficient photogeneration features of perovskite quantum dots (PQDs). The UCF team also devised a unique method for using the device to mimic the synaptic behavior and energy efficiency of the human brain.

Biologically, a synapse acts as a channel of communication between two neurons. One neuron (a presynaptic cell) transmits information to a receiving neuron (a postsynaptic cell). With the UCF invention, the presynaptic signal consists of external stimuli—optical pulses, electrical pulses, or both. The postsynaptic signal is the current obtained across the G-PQD channel.

Technical Details

In one embodiment, the UCF device comprises a substrate with a silicon dioxide layer and a patterned graphene source-drain channel. Grown on the graphene source-drain channel is a perovskite quantum dot layer of methylammonium lead bromide material. The new approach can extend to other 2D materials, including transition metal dichalcogenides and other heterostructures. A method of operating the device as an artificial photonic synapse includes applying a first fixed voltage to a gate of the phototransistor and a second fixed voltage across the graphene source-drain channel. In this example, the presynaptic signal comprises one or more pulses of light or electrical voltage. The postsynaptic signal is a measurement of the current across the graphene source-drain channel. The artificial synapses can strengthen (potentiate) or weaken (depress) based on the appropriate triggers of optical pulses.

Partnering Opportunity

The research team is looking for partners to develop the technology further for commercialization.

Benefit

Market Application