Researchers Demonstrate Microstructure and Charge Yield in Semiconducting Polymers (Fact Sheet), NREL Highlights, Science

关键词: CHARGE CARRIERS;    MICROSTRUCTURE;    MOLECULAR WEIGHT;    NATIONAL RENEWABLE ENERGY LABORATORY;    POLYMERS;    POWER GENERATION;    PROCESSING NREL HIGHLIGHT;    MICROSTRUCTURE;    SEMICONDUCTORS;    CHARGE YIELD;    POLYMERS;    Chemical and Material Sciences;   

DOI  :  10.2172/1035397
RP-ID  :  NREL/FS-5900-53384
PID  :  OSTI ID: 1035397
Others  :  TRN: US201205%%110

美国|英语

来源: SciTech Connect

【 摘 要 】

Microstructure determines the yield of free charge in neat semiconducting polymers. Understanding the fundamental photophysics of poly(3-hyxylthiophene) films, and that of conjugated polymers in general, is essential if we are to realize their full potential as low-cost active layers for coal-competitive solar power generation. Yet, the value of one of the most basic photophysical parameters of these materials - the yield of free charges upon photoexcitation of neat films - has remained controversial because of a wide variation between previous measurements. Researchers at the National Renewable Energy Laboratory (NREL) have resolved this controversy by showing that the yield of free charges depends sensitively on the solid-state microstructure of the film. The microstructure was varied systematically through control of the polymers molecular weight and processing conditions, while the charge carrier yield was measured using time-resolved microwave conductivity - a unique technique to which only a few groups in the world have access. The researchers found that the yield of long-lived free charges depends on the co-existence of amorphous and crystalline domains in the polymer, and this behavior was attributed to charge separation at the interface between these two domains of order.