Efficiency Improvement of Organic Photovoltaic Cells by Nano-Structure and Molecular Orientation Controls

Pr. Tetsuya TAIMA

Nanomaterials Research Institute (NanoMaRi), Kanazawa University, Japan.

A bulk heterojunction (BHJ) structure by co-evaporation of organic photovoltaics (OPVs) provides the large donor-acceptor interface, which facilitates efficient charge separation. However, it is difficult to control directly the morphology of co-evaporated BHJ layer because of random blend of donor and acceptor molecules. Many efforts have been made for structure control of BHJ layer by introducing a new substitute in molecule and combining additive molecules in solution. Recently, we reported highly efficient OPV cells by inserting CuI molecular orientation control layer under the zinc phthalocyanine (ZnPc):C60 co-evaporated BHJ layer. It is estimated that higher light absorption coefficient was obtained by controlled ZnPc lying-down molecular orientation due to π-d interaction between ZnPc and CuI. However, information of the ZnPc molecular orientation in ZnPc:C60 film has not been obtained by various measurements, such as XRD, XAFS, and TEM, due to its low crystallinity in ZnPc:C60 film. Hence, we report that the identification of molecular orientation in ZnPc:C60 film by Infrared reflection absorption spectroscopy (IR-RAS), which is enabled to measure the molecular orientation in amorphous film. We succeed in calculating the molecular orientation angle in co-evaporated films on various substrates by IR-RAS.


Pr. Tetsuya TAIMA : Professor at Nanomaterials Research Institute (NanoMaRi), Kanazawa University, Japan, since 2018.

2002 : Doctor Degree. Department of Applied Chemistry, School of Engineering, Tohoku University.

2002-2004 : Post-Doctoral Researcher (JSPS Research Fellowship). National Institute of Advanced Industrial Science and Technology (AIST).

2005-2011 : Research Scientist. Permanent researcher at Research Center for Photovoltaics (RCPV), AIST.

2009-2015 : PRESTO Researcher (Concurrent post). Project member of Precursory Research for Embryonic Science and Technology (PRESTO) at Japan Science and Technology Agency (JST) is the award to excellent researchers.

2012-2015 : Associate Professor (Tenure Track). RSET, Kanazawa University.

2015-2017 : Associate Professor / Unit leader (Tenure Track). InFiniti, Kanazawa University.

2017-2018 : Professor / Unit leader. InFiniti, Kanazawa University.