Organic Solar Cells Using Transparent SnO2–F Anodes
Organic Solar Cells Using Transparent SnO2–F Anodes
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DOI：
10.1002/adma.200600797
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发表时间：
2006-08
影响因子：
29.4
通讯作者：
Fan Yang;Stephen R. Forrest
中科院分区：
文献类型：
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作者：
Fan Yang;Stephen R. Forrest
有机太阳能电池由于其易于制造和与柔性基板的兼容性而作为实现低成本太阳能转换的手段而引起关注。传统的有机分子光伏（PV）器件和发光二极管（OLED）通常生长在透明的氧化铟锡（ITO）阳极上，其也广泛用于平板显示器（FPD）。In的稀缺性，沿着平板显示器产量的迅速扩大，导致ITO涂层玻璃基板的价格飙升，目前的价格比2003年高出十倍。替代的透明导电氧化物如掺杂的SnO2或ZnO已被用作染料敏化、CdTe、微晶Si和非晶Si PV器件中的电极。有机小分子或聚合物器件，其活性层通常厚度<1000 A，由于这些氧化物变体的显著表面粗糙度特性，可以容易地短路。然而，F掺杂的SnO2（SnO2-F）涂覆玻璃的成本不到ITO涂覆玻璃的三分之一。虽然已经有使用SnO2-F作为聚合物OLED和太阳能电池的透明阳极的报道，但据我们所知，还没有基于SnO2-F阳极的效率大于0.1%的有机异质结（HJ）PV电池的证明。在这里，我们报告了SnO2-F阳极上的铜酞菁（CuPc）/C60 HJ PV电池[8]，其在1个太阳模拟AM 1.5 G（AM：空气质量; G：全局）照明下的功率转换效率为2.5%。有机层通过有机气相沉积（OVPD）生长，其能够完全覆盖粗糙的氧化物表面，有效地防止相对的阴极和阳极接触之间的短路。此外，我们表明，通过控制有机膜的形态，我们可以生长的供体-受体（DA）接口到一个三维的叉指体HJ（BHJ）结构，导致功率转换效率的近两倍的类似设备与平面异质界面。如图1a所示，750 nm厚的SnO 2-F涂层玻璃基板在可见光范围内的透射率为70 - 80%，比具有150 nm厚ITO涂层的玻璃低约10%。两种基材的吸收在小于350 nm的波长处具有高能量截止，这意味着透明窗口与太阳辐射光谱的匹配。SnO 2-F涂覆的玻璃的薄层电阻小于12 X/sq，低于ITO涂层玻璃（15 X/sq.）高透明小电阻C O M M U N IC A TI O N S
Organic solar cells have attracted attention as a means to achieve low-cost solar-energy conversion owing to their ease of manufacture and compatibility with flexible substrates. Conventional organic molecular photovoltaic (PV) devices and light-emitting diodes (OLEDs) are typically grown on transparent indium tin oxide (ITO) anodes that are also widely used for flat-panel displays (FPDs). The scarcity of In, along with the rapid expansion of FPD production, has resulted in a soaring price of ITO-coated glass substrates, with the current price up to ten times greater than in 2003. Alternative transparent conducting oxides such as doped SnO2 or ZnO have been used as electrodes in dye-sensitized, CdTe, microcrystalline Si, and amorphous Si PV devices. Organic small-molecule or polymeric devices, with active layers typically < 1000 A thick, can readily be shorted owing to the pronounced surface-roughness characteristic of these oxide variants. Nevertheless, the cost of F-doped SnO2 (SnO2–F)coated glass is less than one third that of ITO-coated glass. While there have been reports of using SnO2–F as the transparent anode for polymeric OLEDs and solar cells, to our knowledge there has yet to be a demonstration of an organic heterojunction (HJ) PV cell based on SnO2–F anodes with an efficiency greater than 0.1 %. Here, we report on copper phthalocyanine (CuPc)/C60 HJ PV cells on SnO2–F anodes [8] with a power conversion efficiency of 2.5 % at 1 sun simulated AM 1.5 G (AM: air mass; G: Global) illumination. The organic layers were grown by organic vapor-phase deposition (OVPD) that enabled complete coverage of the rough oxide surface, effectively preventing shorts between opposing cathode and anode contacts. In addition, we show that by controlling the organic-film morphology, we can grow the donor–acceptor (D–A) interface into a three-dimensional interdigitated bulk HJ (BHJ) structure, resulting in power-conversion efficiencies nearly twice those of analogous devices with a planar heterointerface. As shown in Figure 1a, the 750 nm thick SnO2–F-coated glass substrates have 70–80 % transmittance in the visible range, or approximately 10 % less than that for glass with 150 nm thick ITO coatings. The absorption of both substrates has a high-energy cutoff at wavelengths less than 350 nm, implying a match of the transparency window to that of the solar radiation spectrum. The sheet resistance of SnO2–F-coated glass is less than 12 X/sq., lower than that of ITO-coated glass (15 X/sq.) The high transparency and small resistance C O M M U N IC A TI O N S