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Phenolic additives and their effects on blend morphologies of bulk heteojunctions

Controlling the blend morphology is one of the ways to achieve high power conversion efficiency in organic bulk heterojunction (BHJ) photovoltaic device. One sample yet effective method is ¡§ additive¡¨ approach, which involves the addition of a small concentrations of additive into the blend of donor/acceptor dissolved in solution. When adding small concentrations of additives in solution, we can change the donor/acceptor of internal micro-structure and films of morphology. In this work, we performed a systematic study of the effect of nanocrystals of phenolic additives, such as the small concentrations of 4,4'-Sulfonyldiphenol(BPDT), 4,4'-Dihydroxybiphenyl(BP) and Biphenyl-4,4¡¦-dithiol(BPS), on the nanoscals phase separation of and P3HT:PCBM blends and consequently, the power conversion efficiency(PCE) of the devices. The extent of the additive-induced phase separation and crystallize of P3HT is related to the additive acidity constant (pKa) and the degree of interaction between the additive and P3HT/PCBM, as evident from X-ray diffractmeter, UV-Vis spectrometer, Raman spectrometer and current density-voltage characteristic data. Lastly, PCE as increasing as 25% and short current increasing as 15% can be achieved in an optimally phase-separated blend due to an improvement in the charge dissociation and a dcrease in bimolecular recombination and parallel resistance.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0707111-174947
Date07 July 2011
CreatorsGong, Fang-Lin
ContributorsWen-Yao Huang, Yu-Kai Han, Li-Yin Chen, Mei-Ying Chang, Wen-Jun Zheng
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0707111-174947
Rightsnot_available, Copyright information available at source archive

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