High Performance Roll-to-Roll Coated All-Polymer Solar Cells
Abstract
Organic solar cells (OSC) hold the promise of being a sustainable energy source in a lightweight,flexible form factor with low-cost manufacturing and installation to allow short energy recoverytimes. Although the performance of organic solar cells has greatly improved over the past fewyears in laboratory-fabricated devices, the high performance acceptor materials are largelylimited to fullerene-based small molecules, and even with these lab-scale high performingmaterials, the best reported power conversion efficiency (PCE) for roll-to-roll printed bulkheterojunction (BHJ) active layers are still only 2-3%. Besides, the high cost, the limited opticalabsorption of fullerenes, and the long-term device stability issue prohibits the widespreadadoption of OSCs. In contrast, all-polymer solar cells are highly processable and stable, and theoptical properties and BHJ morphology can be tuned by tuning the chemical structures of thedonor and the acceptor polymers.The device performance of all-polymer solar cells is still low comparing to fullerene-basedcompetitors, and it is imperative that we develop molecular design and processing rules for highperformance all-polymer solar cells. We developed a lab-scale roll-to-roll coater and used it tosuccessfully print all-polymer solar cells with 5% PCE over a 10 cm2 area. This is a significantbreakthrough in roll-to-toll processed OSCs and our findings open up the possibility to develop apath towards large-scale production of stable high efficiency devices. This initial successprovides us a unique opportunity to investigate the requirements for all-polymer solar cells to laya path towards performance that will be of practical importance.In this project, we will advance our knowledge of molecular design and morphology control torealize roll-to-roll coated lightweight, high performance, highly stable and scalable all-polymersolar cells. This will be achieved through systematic molecular design with feedback fromdetailed structural and device performance characterizations. Polymer side chains for availablebackbones will be engineered to control the aggregation behavior with a designed syntheticroute. A set of synchrotron-based x-ray techniques will be used to understand donor and acceptorpolymer behaviors in solution, during solution coating and the morphology of the resulting dryfilms for systematically designed processing conditions. Focusing on systematically modificationof polymer acceptor design and utilizing the already widely available donor polymers, we willperform detailed structural and performance characterizations to obtain molecular design androll-to-roll coating guiding rules to achieve optimized performance with capability of scale up.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 03, 2017
- Source ID
- N000141712214
Entities
People
- Zhenan Bao
Organizations
- Office of Naval Research
- Stanford University
- United States Navy