Highly Efficient Inkjet-Printed Organic Photovoltaic Cells

• Published in: Japanese Journal of Applied Physics 2010-05, Vol.49 (5), p.05EB03-05EB03-5
• Main Authors: Jung, Jaewook, Kim, Donghwan, Lim, Jongsun, Lee, Changjin, Yoon, Sung Cheol
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.49.05EB03

In this article, we report the development of inkjet printing technique for the fabrication of bulk heterojunction organic photovoltaic cells (OPVs). We have demonstrated highly efficient OPV with a mixture of poly(3-hexylthiophene)s (P3HT) and 1-[3-(methoxycarbonyl)propyl]-1-phenyl[6.6]C61 (PCBM) as an inkjet-printed photoactive layer. Especially, 3.8% of power conversion efficiency (PCE) and 0.68 V of open circuit voltage ($V_{\text{oc}}$) can be obtained by using the chlorobenzene as a solvent. This value is the highest performance in P3HT:PCBM based OPV system by now. We reveal that substantial improvements can be realized by nano-structured heterojunction after inkjet printing and this technique is one of the promising fabrication methods for organic photovoltaic cells. Also, we have designed and fabricated five-series connected large area (18 cm 2 ) inkjet-printed OPVs using the patterned indium tin oxide (ITO) with Au bus-electrode to minimize the efficiency drop due to the surface resistance of ITO. Consequently, 1.25% of power conversion efficiency can be obtained with a short circuit current of 1.24 mA/cm 2 , a fill factor of 0.32, and an open circuit voltage of 3.2 V.