SBIR-STTR Award

Manufacturing high efficiency physically robust flexible OSC modules with long lifetimes
Award last edited on: 3/16/2023

Sponsored Program
STTR
Awarding Agency
DOD : Navy
Total Award Amount
$1,240,000
Award Phase
2
Solicitation Topic Code
N21A-T009
Principal Investigator
Brendan O'Connor

Company Information

PolyPV LLC

201 Promontory Point Drive
Cary, NC 27513
   (413) 530-0895
   N/A
   N/A

Research Institution

North Carolina State University

Phase I

Contract Number: N68335-21-C-0350
Start Date: 6/7/2021    Completed: 12/7/2021
Phase I year
2021
Phase I Amount
$240,000
The main challenges in commercializing organic solar cell modules are translating the recently achieved high power conversion efficiency to larger area monolithic modules produced with scalable fabrication techniques, and improve operation lifetimes of the modules. Device degradation in organic solar cells can include intrinsic morphological changes over time, intrinsic chemical reactions at electrode interfaces or diffusion/interpenetration of the electrode interlayers with the active layer, and finally extrinsic oxygen and water infiltration that causes photo-oxidation. We view the intrinsic stability problems as more challenging than the processing and scaling requirements, and target improving the intrinsic stability of organic solar cell to improve their commercial viability. This will be achieved through the following objectives: (1) Benchmark the operational stability of model high-efficiency organic solar cells and identifying intrinsic degradation pathways; (2) Design electrode and charge transport layers that minimize degradation pathways associate with active layer interfaces; (3) Utilize recently developed active layer material selection and processing design framework that improves morphological stability; (4) Employ UV light management technologies into the solar cells; and (5) Use processing methods compatible with mass production to fabricate efficient and stable solar modules with power conversion efficiency over 13% for cells that are 1 cm2 with less than 10% performance loss to break-in over 100 hours unpackaged and 1000 hours packaged

Benefit:
Rugged, lightweight, and flexible solar power would greatly enhance military defense operations and have significant commercial opportunities for portable power sources for sport and recreation use, as well as wearable sources of power for continuous health monitoring applications. For military applications, durable and portable solar power would considerably reduce battery weight by supplying power to the growing number of electronic devices on the battlefield. For example, batteries make up as much as 20% of the weight a Marine infantryman typically carries. In addition to meeting military needs, a local power source will also reduce battery needs in wearable electronic applications. The wearable electronics market value in 2020 was estimated to be $37.1 billion, and revenue is forecasted to be $104.4 billion by 2027. Organic semiconductors consist of van der Waals bonds that are inherently more flexible than their covalently bond counterparts. These materials also have very low densities and are applied as extremely thin films in photovoltaic applications (~200 nm) resulting in solar cells with extremely high power on a per unit weight basis. Additionally, organic semiconductors can be solution-processed in ambient environments onto low-cost and flexible plastic substrates. These characteristics make organic semiconductors an excellent candidate for successful low-weight, durable solar power. For organic solar cells to be commercially viable there is a need to make efficient module-scale devices with long operational lifetimes. The research and development that will be pursued as part of this award will directly address these challenges providing a viable path to flexible organic solar cell commercialization.

Keywords:
Lifetime, Lifetime, Organic Electronics, stability, photovoltaics, flexible, organic solar cells

Phase II

Contract Number: N68335-23-C-0036
Start Date: 12/22/2022    Completed: 12/31/2024
Phase II year
2023
Phase II Amount
$1,000,000
In direct support of the research problem of the STTR 2021.A Organic Solar Cell Processing and Product Development topic, the main technical objectives are to develop a prototype flexible >50 cm2 OPV module with >11% performance and a geometric fill factor >90%. Furthermore, these modules are to be fabricated with scalable methods such as slot die coating on ITO coated PET substrates. The intrinsic stability of the tailored and stabilized active layer, enhanced by an encapsulation barrier, will provide a module lifetime of >5 years with intermittent light exposure corresponding to 0.1-0.5 sun-years. Module lifetime will be evaluated by mechanical stress tests, repeated extreme temperature cycling (20 C - 110 C), and high light intensity testing with up to 80 suns. The targeted fabrication yield is >90% and modules will be impact-resistant to hail (following ASTME E1038-10). The fundamental and applied knowledge to achieve these objectives will be researched and developed, and will comprise accelerated light stability testing, mechanical characterization, and electrical testing. The active layer donor polymer will include PTQ10, due to attractive cost and processing characteristics. Packaging with favorable W/kg, W/volume and $/W capacity (Wp) will be targeted. The business model will be developed, including product concepts for military and recreational applications, and cost analysis for appropriate markets. Partnerships for scaled-up product and field tests will be sought. These technical goals represent significant advances over phase I results that achieved a three-cell mini-modules with 3 cm2 total device area and 11% performance on rigid substrates utilizing blade-coating, with individual spin-coated 1 cm2 cells achieving >13% efficiency.

Benefit:
PolyPV will target modules with rated capacity of 50 W 500 W that are lightweight and mechanically flexible. These attributes will provide a unique opportunity to be used as remote power sources for the military (reduce warfighter weight and reduce logistics tail of military operations) and for recreational outdoor activities such as camping. In addition, smaller area modules will be targeted that are under 5 W capacity that will be directed towards the healthcare and smart device markets. In the healthcare industry, continuous health monitoring devices such as oximetry, ECGs, and glucose monitoring can be powered locally to remove the need for charging or wires. These target markets will allow for early adoption of the technology where customers are more willing to pay a premium for product features. Current flexible solar cell technologies on the market are based largely on CIGS and amorphous silicon. Both of these technologies have limited flexibility and efficiency. In these technologies, the efficiency of commercial products are often lower than 10% and have limited bending radius of greater than several centimeters. Organic solar cells have the potential for significant increase in efficiency with lower weight, and with greater flexibility and toughness. All these attributes contribute to a competitive advantage for the target markets. There are several commercial OPV entities, including Heliatek and Next Energy, that focus on building integration or windows and not on the target markets outlined above. In addition, Infinity PV is a company that focuses on selling demonstration printed cells and associated processing products. The focus of Infinity PV is on processing small-scale solar cells, with emphasis on printing development. We differentiate our company by developing advanced technologies that drive the desired performance metrics of efficiency, operating lifetime, and mechanical stability. These characteristics will be optimized through materials and ink development, interface and device designs, and flexible encapsulation. Advancing these current limitations will drive large-scale organic solar cell adoption. The team brings a competitive advantage through their significant experience in organic solar cell technology development, from processing and morphology optimization to mechanical and optical stability (see 1.3). Through this deep understanding of the technology, we can collectively make significant strides in meeting the performance requirements for broad commercial adoption.

Keywords:
flexible solar power, organic solar cells, stability