Simultaneous enhancement in both large-area coatability and photovoltaic performance of inverted organic solar cells with co-solvent

• Published in: Solar energy materials and solar cells 2014-01, Vol.120, p.197-203
• Main Authors: Hong, Yun-Ru, Chen, Pin-Kuan, Wang, Jen-Chun, Lee, Ming-Kun, Horng, Sheng-Fu, Meng, Hsin-Fei
• Format: Article
• Language: English
• Subjects: Applied sciences; Blade coating; Carrier transport; Co-solvent; Coating; Energy; Evaporation; Exact sciences and technology; Hexanes; Large area manufacturing; Light soaking; Natural energy; Organic solar cells; Photovoltaic cells; Photovoltaic conversion; Soaking; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2013.09.002

We report our observation of simultaneous enhancement in large-area coatability and photovoltaic performance for blade-coated inverted P3HT:PCBM organic solar cells with DCB:hexane co-solvent. The addition of hexane improves greatly the wettability of P3HT:PCBM blend layer on Cs2CO3 treated ITO and leads to excessively higher P3HT surface concentration due to the incongruent evaporation of hexane and DCB. A post-processing light soaking was found to further improve the photovoltaic performance for blade-coated devices prepared with co-solvent by adjusting the P3HT surface concentration ratio for more favorable carrier transport, as evidenced by the disappearance of current suppression at forward bias and significant increase in Voc after light soaking. Since large-area manufacturing is the key to full commercialization of organic solar cells, the use of co-solvent, combined with light soaking, may be crucial for the development of inverted organic solar cells. ●Co-solvent was found to enhance both the large-area coatability and the photovoltaic performance of the resulted inverted organic solar cells.●The blade-coated blend layer prepared with co-solvent exhibits excessively high P3HT surface concentration due to incongruent evaporation.●Post-processing light soaking further improves the photovoltaic performance of the blade-coated inverted solar cells with co-solvent.●The use of DCB:hexane co-solvent, combined with light soaking, can be useful for large-area manufacturing of inverted organic solar cells.