Year of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Department of Chemistry.

Principal Supervisor

Wong, Ricky Man Shing


Copolymers, Solar cells, Synthesis




Naphthonaphtho[2,1-b:3,4-b']dithiophene is a good electron-rich building block for p-type semiconducting materials and has been extensively studied in our group. Various donor-acceptor type copolymers based on naphtho[2,1-b:3,4-b']dithiophene were designed and synthesized for high-performance bulk heterojunction solar cell applications. The structure-property relationship of these copolymers with respect to the influence of alkyl side-chain position and chain length, fluorination substitution effect as well as acceptor group effect with different electron withdrawing ability were also investigated. The results of the PV device performance based on these copolymers indicated that the device efficiency was sensitive to the position of the alkyl side-chains attached, which could cause non-planarity of polymer backbone. The resulting naphthodithiophene-based copolymer with shorter side-chains afforded higher device efficiency. The incorporation of fluorine atoms into the copolymers leading to the poor solubility caused a decrease in the device performance compared to the non-fluorinated counterparts. The copolymer with thiadiazol[3,4-c]pyridine as an electron-deficient unit also showed promising device performance with efficiency up to 5.10%. Among all the copolymers designed and synthesized, three copolymers namely PNB-4, PNB-C2,6 and PNTP exhibited excellent preliminary device performance with a PCE more than 5.0% showing potential for further device optimization and development.


Thesis (Ph.D.)--Hong Kong Baptist University, 2013.;Principal supervisor: Professor Wong Ricky M S.;Includes bibliographical references.


The author retains all rights to this work. The author has signed an agreement granting HKBU a non-exclusive license to archive and distribute their thesis.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.