Record Details
Design of organic ternary blends and small-molecule bulk heterojunctions: photophysical considerations
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Design of organic ternary blends and small-molecule bulk heterojunctions: photophysical considerations |
| Names |
Rajesh, Kallarakkal Ramakrishnan
(creator) Paudel, Keshab (creator) Johnson, Brian (creator) Hallani, Rawad (creator) Anthony, John (creator) Ostroverkhova, Oksana (creator) |
| Date Issued | 2015-01-09 (iso8601) |
| Note | This is the publisher’s final pdf. The published article is copyrighted by the Society of Photo-Optical Instrumentation Engineers and can be found at: http://photonicsforenergy.spiedigitallibrary.org/journal.aspx?journalid=98. |
| Abstract | We explored relationships between photophysical processes and solar cell characteristics in solution-processable bulk heterojunctions (BHJs), in particular: (1) polymer donor:fullerene acceptor:small-molecule (SM) nonfullerene acceptor, (2) polymer donor:SM donor:SM nonfullerene acceptor, and (3) SM donor:SM nonfullerene or fullerene acceptor. Addition of a nonfullerene SM acceptor to “efficient” polymer:fullerene BHJs led to a reduction in power conversion efficiency (PCE), mostly due to decreased charge photogeneration efficiency and increased disorder. By contrast, addition of an SM donor to “inefficient” polymer:SM nonfullerene acceptor BHJs led to a factor of two to three improvement in the PCE, due to improved charge photogeneration efficiency and transport. In most blends, exciplex formation was observed and correlated with a reduced short-circuit current (J[subscript sc]) without negatively impacting the open-circuit voltage (V[subscript oc]). A factor of ∼5 higher PCE was observed in SM donor:fullerene acceptor BHJs as compared to SMBHJs with the same SM donor but nonfullerene acceptor, due to enhanced charge carrier photogeneration in the blend with fullerene. Our study revealed that the HOMO and LUMO energies of molecules comprising a blend are not reliable parameters for predicting V[subscript oc] of the blend, and an understanding of the photophysics is necessary for interpreting solar cell characteristics and improving the molecular design of BHJs. |
| Genre | Article |
| Topic | organic solar cells |
| Identifier | Rajesh, K. R., Paudel, K., Johnson, B., Hallani, R., Anthony, J., & Ostroverkhova, O. (2015). Design of organic ternary blends and small-molecule bulk heterojunctions: photophysical considerations. Journal of Photonics for Energy, 5(1), 057208. doi:10.1117/1.JPE.5.057208 |
