Solar Cell Technology   

All solar energy capture devices employ a photon capture agent and charge mobility medium. In traditional implementations, photon capture is achieved with either molecular chromophores or a semiconductor material both of which provide only a narrow absorption profile. Such implementations are inherently limited in their ability to capture photons due to the narrow absorption profile of the photon capture agent. Typically, the charge mobility medium is a semiconductor. However, critical to the ability of a PV to generate current is the efficiency of the photon capture agent in facilitating (or inducing) electron hole pair (exciton) migration. How specifically the induction occurs depends on the type of photon capture agent: With molecular chromophores, charge injection from a discrete molecular excited state into a semiconductor substrate is the operable mechanism. Here, so called ‘back transfer’ of the injected electron is prevalent, thus inherently limiting the utility of such implementations. With semiconductor photon capture agents, photon induced electron hole pair migration across the p-n junction is the operable mechanism. The actual travel of photo-induced current across the p-n junction is relatively efficient in single crystal materials, and as such it has been estimated that 70% of the losses within silicon solar cells derives from the inefficient absorptive properties of the material.      

 Currently, state of the art technologies employ semiconductor nanoparticles (e.g., quantum dots) as the photon capture agent. Quantum dots offer the ability to tailor the absorptive properties of a PV. Introducing a variety of quantum dots into the cell provides a broad absorptive profile thereby removing the inefficiencies associated with photon capture. The quantum dots act similarly to a molecular chromophore; upon absorption of a photon, an exciton is formed on the quantum dot and the electron is transferred into a semiconductor medium. Similar to molecular chromophores, these systems will be subject to back transfer and photon capture agent degradation. Moreover, the quantum dots are composed of metal chalcogenides, wherein the metals are cadmium and lead, which introduce significant regulatory problems.

GoNano Technologies approach to nano enabled solar cells provides a unique platform for the development of highly efficient PV technologies. GoNano employs proprietary nanoparticle compositions as the photon capture agent. Similar to quantum dots, the absorptive properties of the particles can be controlled through modulation of the size and shape distribution. Importantly, the GoNano process allows for such controls to be exerted during the deposition process and is adaptable to a range of materials thus enabling rapid, flexible production.

GoNano has developed simple prototypes, and is currently focusing on the development of optimized systems for photocurrent generation. The GoNano promise is a high efficiency solar cell produced at costs comparable, if not better than current thin film solar cell technologies.