Understanding Assembly Pathways of Conjugated Polymers: Solution-Processable High Temperature Organi
Abstract
This proposed project is part of our ongoing efforts to develop solution processable materials for hightemperature organic electroni,cs, which involves high temperature polymer dielectrics, semiconductors, andconductors. In phase I (current project), we have succes,sfully conceived and developed a general approach toachieve thermally stable semiconducting polymer blends that could withstand high, temperature for a prolongedperiod. Built on this conceptual work, we have established the design criteria for conjugated polymers a,nd theirblends to achieve superior operational stability under thermal stress. We also studied the impact of devicefactors on the th,ermal stability, such as contact resistance and bias stress. As a result, we have deliveredpolymer field effect transistors that cou,ld maintain high performance at up to 200C in air for more than 24hours. This is unprecedented in literature. We also have a better, understanding on charge transport in OFET atelevated temperatures. Our studies on high temperature organic conductors have raised g,rowing interests in thecommunity. For instance, investigation of transistor performance under thermal stress is gradually becoming a,routine practice. It is worth mentioning that Liu et al have recently reported that transistors based on barcoating aligned P(NDI2OD,-T2)/PAN displayed a stable electronic transport from 200-460 K with an electron mobilityhigher than 3.5 cm2V-1s-1. However, there a,re some remaining questions to be addressed. First, the failure modeof high temperature organic semiconductors is still not clear. S,econd, the long-term thermal stability is notfully evaluated in any of the reported systems. Third, it remains to be explored how di,electrics, semiconductorsand conductors can be co-designed to improve device operational stability under thermal stress.In the propo,sed phase II (this proposal), we will shift our focus onto high temperature organic conductors whilewe continue to seek solutions fo,r the above-mentioned questions. Organic conductors have a very rich history andare often made from doping of conjugated polymers. N,otable examples include doped polyacetylene, polypyrrole andPEDOT-PSS. However, organic conductors that can reliably perform at elev,ated temperatures are rare, resultingfrom weak and complex interactions between dopants and conjugated polymers. To achieve high tem,perature organicsemiconductors, the prerequisite criteria is to ensure chemical integrity and morphological robustness ofpolymer-dop,ant composites. Through co-design of polymers and dopants, superior chemical integrity is expected forthe doped composites, which ar,e resilient in face of external stressors such as oxygen, moisture,photoexcitation, and thermal stress. We will probe the impact of,processing parameters on doping efficiency andstability. We will also explore ion exchange and crosslinking strategies to improve mo,rphological robustnessunder the prolong thermal stress. Successful execution of the project will lead to solution-processable organi,cconductors with conductivities approaching 1000 S/cm at elevated temperatures (150 oC and higher) for a prolongtime (1000 h and lon,ger).This project is requesting $ 605K over four years. Approved for public release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 05, 2022
- Source ID
- N000142212177
Entities
People
- Jianguo Mei
Organizations
- Office of Naval Research
- Purdue University
- United States Navy