One-Step Synthesis of Precursor Oligomers for Organic Photovoltaics: A Comparative Study between Polymers and Small Molecules
2015 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 49, 27106-27114 p.Article in journal (Refereed) PublishedText
Two series of oligomers TQ and rhodanine end-capped TQ-DR were synthesized using a facile one-step method. Their optical, electrical, and thermal properties and photovoltaic performances were systematically investigated and compared. The TQ series of oligomers were found to be amorphous, whereas the TQ-DR series are semicrystalline. For the TQ oligomers, the results obtained in solar cells show that as the chain length of the oligomers increases, an increase in power conversion efficiency (PCE) is obtained. However, when introducing 3-ethylrhodanine into the TQ oligomers as end groups, the PCE of the TQ-DR series of oligomers decreases as the chain length increases. Moreover, the TQ-DR series of oligomers give much higher performances compared to the original amorphous TQ series of oligomers owing to the improved extinction coefficient (epsilon) and crystallinity afforded by the rhodanine. In particular, the highly crystalline oligomer TQ5-DR, which has the shortest conjugation length shows a high hole mobility of 0.034 cm(2) V-1 s(-1) and a high PCE of 3.14%, which is the highest efficiency out of all of the six oligomers. The structure-property correlations for all of the oligomers and the TQ1 polymer demonstrate that structural control of enhanced intermolecular interactions and crystallinity is a key for small molecules/oligomers to achieve high mobilities, which is an essential requirement for use in OPVs.
Place, publisher, year, edition, pages
AMER CHEMICAL SOC , 2015. Vol. 7, no 49, 27106-27114 p.
crystallinity; amorphous; one-step method; oligomers; hole mobility; organic photovoltaics
Electrical Engineering, Electronic Engineering, Information Engineering Biological Sciences
IdentifiersURN: urn:nbn:se:liu:diva-123746DOI: 10.1021/acsami.5609460ISI: 000366873900011OAI: oai:DiVA.org:liu-123746DiVA: diva2:892985
Funding Agencies|China Scholarship Council; program for the Excellent Doctoral Dissertations of Guangdong Province [ybzzxm201114]; Guangdong Natural Science Foundation [S2012030006232]; Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy [DE-AC02-05CH11231]2016-01-112016-01-112016-01-11