This Small Business Innovation Research Program (SBIR) Phase I project explores a transformational visibly transparent photovoltaic (PV) device. Building-integrated photovoltaics (BIPV) are a promising energy pathway to capturing large areas of solar energy and increasing U.S. building efficiency at the point of utilization. However, the widespread adoption of such technologies is severely hampered by the cost and aesthetics associated with mounting traditional PV modules on siding and windows. Here, these challenges are overcome by exploiting the excitonic character of molecular and organic semiconductors that lead to "oscillator bunching" to produce PV architectures with selective absorption, i.e. exhibiting visible minima and ultra-violet (UV) and near-infrared (NIR) maxima, uniquely distinct from the band-absorption of traditional inorganic semiconductors. By using excitonic molecular semiconductors with structured absorption in the NIR/UV these devices are simultaneously optimized for high power conversion efficiency, visible light transmission, and color rendering index. Accordingly, the aim of this program is to reach relevant size, lifetime, aesthetic, and form-factor objectives that will demonstrate the feasibility of developing the proof-of-concept prototypes into a commercially viable, transparent, PV window film that can be applied to glass surfaces at the point of window fabrication or as a retrofit on existing windows.
The broader impact/commercial potential of this project enables unprecedented freedom for architectural PV adoption by maintaining the aesthetics of existing building materials and the quality of natural indoor lighting: (1) increasing building efficiency and energy independence by producing electricity at the point of utilization, (2) reducing building cooling demands by rejecting infrared solar heat, supplementing or replacing existing low-E and solar-control window coatings, and (3) achieving low levelized energy costs by piggybacking on the installation, framing, and maintenance of the existing building envelope. Installed window surface area in the U.S. equipped with such films represents hundreds of terawatt-hours of potential energy, comprising energy generation and energy savings. Moreover, this project will result in a core knowledge from which future generations of transparent photovoltaic devices and materials will be designed. Visibly transparent PVs are also amenable to seamless energy harvesting within non-window surfaces such as electronic displays and mobile electronic accessories, enhancing the functionality of those products without impacting aesthetics or functionality. The deployment of transparent PVs, both domestically and abroad, supports American efforts to maintain technological and economic leadership in developing and implementing advanced technologies, by revolutionizing the way electricity is generated and consumed.
This Small Business Innovation Research Phase I project explored a transformational visibly transparent photovoltaic (PV) device. Building integrated photovoltaics (BIPV) are a promising pathway to capturing significant solar energy and increasing US building efficiency at the point of energy utilization. However, the widespread adoption of such technologies is severely hampered by the cost and aesthetics associated with mounting traditional PV modules on siding and windows. Ubiquitous Energy is overcoming these challenges by exploiting the excitonic character of molecular and organic semiconductors that lead to "oscillator bunching" to produce PV architectures with selective absorption, i.e. exhibiting visible minima and ultra-violet (UV) and near-infrared (NIR) maxima, uniquely distinct from the band-absorption of traditional inorganic semiconductors. By using excitonic molecular semiconductors with structured absorption in the NIR/UV these devices are simultaneously being optimized for high power conversion efficiency, visible light transmission, and color rendering index. Accordingly, in this program we reached relevant area, lifetime, aesthetic, and form-factor objectives, which demonstrate the feasibility of developing the proof-of-concept prototypes into a commercially viable, transparent, PV window film that can be applied to glass surfaces at the point of window fabrication or as a retrofit on existing windows. Moreover, as proposed, we succeeded in demonstrating the key elements of device design and fabrication necessary to achieve a prototype transparent PV module. These elements included: (1) investigating the influence of device area on transparent PV device performance, (2) achieving high device yield over hundreds of square centimeters through design of a new robust device architecture, (3) demonstrating a monolithically integrated transparent PV prototype module larger than 100 cm2, and (4) performing an initial investigation of transparent PV device stability in air. The results from Phase I will serve as a platform for additional commercial validation prior to (and during) Phase II, as well as for additional technology development and investment. Moreover, the results lay the groundwork for completing subsequent objectives in Phase II necessary for commercial deployment of transparent PV window films. Broadly, the results of this project will enable unprecedented freedom for architectural PV adoption by maintaining the aesthetics of existing building materials and the quality of natural indoor lighting: (1) increasing building efficiency and energy independence by producing electricity at the point of utilization, (2) reducing building cooling demands by rejecting infrared solar heat, supplementing or replacing existing low-E or solar control window coatings, and (3) achieving low levelized energy costs by piggybacking on the installation, framing, and maintenance of the existing building envelope. Installed window surface area in the US alone, if equipped with such films, represents hundreds of terawatt-hours of potential energy impact from the combination of energy generation and heating/cooling savings. This project has also resulted in a core knowledge from which future generations of transparent photovoltaic devices and materials will be designed. Visibly transparent PVs are also amenable to seamless energy harvesting within non-window surfaces such as electronic displays and mobile electronic devices, enhancing the utility of those products without impacting aesthetics or functionality. The deployment of transparent PVs, both domestically and abroad, supports American efforts to maintain technological and economic leadership in developing and implementing advanced technologies by revolutionizing the way electricity is generated and consumed.
