Mechanical flexibility of transparent PEDOT:PSS electrodes prepared by gravure printing for flexible organic solar cells

• Published in: Solar energy materials and solar cells 2011-12, Vol.95 (12), p.3269-3275
• Main Authors: Cho, Chung-Ki, Hwang, Woo-Jin, Eun, Kyoungtae, Choa, Sung-Hoon, Na, Seok-In, Kim, Han-Ki
• Format: Article
• Language: English
• Subjects: Applied sciences; Bending test; Electrical resistivity; Electrodes; Energy; Exact sciences and technology; Flexibility; Gravure; Gravure printing; Natural energy; Organic solar cells; PEDOT:PSS; Photovoltaic cells; Photovoltaic conversion; Polyethylene terephthalates; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Twisting
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2011.07.009

The mechanical flexibility of transparent poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films printed onto a flexible PET substrate using a gravure printing method was investigated using a lab-made bending test system. Gravure-printed PEDOT:PSS electrodes with a sheet resistance of 359 Ω/square and a transparency of 88.92% showed outstanding flexibility in several types of flexibility tests, including outer/inner bending, twisting and stretching. Notably, the PEDOT:PSS electrode had a constant resistance change (Δ R/ R 0) within an outer and inner bending radius of 10 mm. In addition the stretched PEDOT:PSS electrode showed a fairly constant resistance change (Δ R/ R 0) up to 4%, which is more stable than the resistance change of conventional amorphous ITO electrode. The twisting test revealed that the resistance of the PEDOT:PSS electrode began to increase at an angle of 36° due to delamination of the film from the PET substrate. Despite the high sheet resistance of the PEDOT:PSS electrode the flexible organic solar cells fabricated on the PEDOT:PSS electrode showed a power conversion efficiency of ∼2% (FF: 44.9%, V o: 0.495 V and J sc: 9.1 mA/cm 2), indicating the possibility of using gravure printed PEDOT:PSS as a flexible and transparent electrode for printing-based flexible organic solar cells. [Display omitted] ► Mechanical flexibility of gravure printed PEDOT:PSS investigated. ► Printed PEDOT:PSS electrodes showed outstanding flexibility in flexibility tests. ► Flexible OSCs with PEDOT:PSS electrode showed a PCE of ∼2%.