Browsing by Author "Hong, Yun-Ru"

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Efficient inverted organic solar cells without an electron selective layer
(2011)
Wang, Jen-Chun
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Lu, Cheng-Yueh
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Hsu, Jui-Lin
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Lee, Ming-Kun
;
Hong, Yun-Ru
Inverted organic solar cells which required no electron selective layer were fabricated and their power conversion efficiency was found to improve irreversibly from 1.46% to 4.10% with post-processing light soaking for 2 hours. X-Ray photoelectron spectroscopy characterization revealed further segregation in surface composition at the interface and was found to explain the current density-voltage measurements. In addition, the light soaked devices were found to exhibit extended lifetime as compared to conventional devices. Since no electron selective layer was required, light soaking may be considered as a cost-effective method to achieve efficient inverted organic solar cells.
Enhanced carrier extraction efficiency in organic solar cells with reduced space-charge limited transport by engineered vertical compositional profile
(2012-12-01)
Lee, Ming-Kun
;
Kuo, Tsung-Han
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Kong, Kuo-Wen
;
Hong, Yun-Ru
;
Wang, Jen-Chun
A multi-layered polymer solar cell (PSC) with a graded compositional profile to reduce space-charge limited (SCL) transport was designed and analyzed in details. We found that by increasing the effective carrier lifetime for the slower photo-carriers. SCL effects that degrade the fill factor and the power conversion efficiency can be alleviated in PSCs with a thick active layer. The reduction of SCL effects was evidenced by a diminished dependence of the incident photon-to-electron conversion efficiency (IPCE) on light bias, which also indicates the importance of light bias in characterizing the operating IPCE of PSCs with thick active layers which operate in SCL region. Based on our results, device architecture to enhance FF was proposed. (C) 2012 Elsevier B.V. All rights reserved.
Simultaneous enhancement in both large-area coatability and photovoltaic performance of inverted organic solar cells with co-solvent
(2014-01-01)
Hong, Yun-Ru
;
Chen, Pin-Kuan
;
Wang, Jen-Chun
;
Lee, Ming-Kun
;
Horng, Sheng-Fu
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 V-oc 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. (C) 2013 Elsevier B.V. All rights reserved.