Controlling Number of Indene Solubilizing Groups in Multiadduct Fullerenes for Tuning Optoelectronic Properties and Open-Circuit Voltage in Organic Solar Cells
详细信息 查看全文
- 作者：Hyunbum Kang ; Chul-Hee Cho ; Han-Hee Cho ; Tae Eui Kang ; Hyeong Jun Kim ; Ki-Hyun Kim ; Sung Cheol Yoon ; Bumjoon J. Kim
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2012
- 出版时间：January 25, 2012
- 年：2012
- 卷：4
- 期：1
- 页码：110-116
- 全文大小：369K
- 年卷期：v.4,no.1(January 25, 2012)
- ISSN：1944-8252
文摘
The ability to tune the lowest unoccupied molecular orbital (LUMO)/highest occupied molecular orbital (HOMO) levels of fullerene derivatives used as electron acceptors is crucial in controlling the optical/electrochemical properties of these materials and the open circuit voltage (Voc) of solar cells. Here, we report a series of indene fullerene multiadducts (ICMA, ICBA, and ICTA) in which different numbers of indene solubilizing groups are attached to the fullerene molecule. The addition of indene units to fullerene raised its LUMO and HOMO levels, resulting in higher Voc values in the photovoltaic device. Bulk-heterojunction (BHJ) solar cells fabricated from poly(3-hexylthiophene) (P3HT) and a series of fullerene multiadducts-ICMA, ICBA, and ICTA showed Voc values of 0.65, 0.83, and 0.92 V, respectively. Despite demonstrating the highest Voc value, the P3HT:ICTA device exhibited lower efficiency (1.56%) than the P3HT:ICBA device (5.26%) because of its lower fill factor and current. This result could be explained by the lower light absorption and electron mobility of the P3HT:ICTA device, suggesting that there is an optimal number of the solubilizing group that can be added to the fullerene molecule. The effects of the addition of solubilizing groups on the optoelectrical properties of fullerene derivatives were carefully investigated to elucidate the molecular structure鈥揹evice function relationship.