梯度掺杂体异质结对有机太阳能电池光电转换效率的影响

基于传统的体异质结有机太阳能电池结构, 对结构中的混合层改用梯度掺杂的方法, 在AM1.5, 100 mW/cm²光照下, 使得器件的短路电流由原来的7.72 mA/cm²提高到了9.18 mA/cm², 相应的光电转换效率提高了25%. 器件性能的提升归因于梯度掺杂体系的引入使得体异质结混合层中同一材料分子之间形成了较好的连续网络结构, 降低了器件的串联电阻, 提高了电极对载流子的收集效率, 从而提高了器件的光电转换效率. 关键词： 有机太阳能电池 体异质结 梯度掺杂

Influence of gradient doping on photoelectric conversion efficiency of organic photovoltaic devices

On the basis of the traditional bulk heterojunction structure, we introduce a method of gradient doping in the mixing layer to improve photoelectric conversion efficiency (η_p) of organic photovoltaic device (OPV). One of the devices with the structure of ITO/CuPc (10 nm)/CuPc:C₆₀ (2:1) (4 nm)/CuPc:C₆₀ (1.5:1) (4 nm)/CuPc:C₆₀ (1:1) (4 nm)/CuPc:C₆₀ (1:1.5) (4 nm)/CuPc:C₆₀ (1:2) (4 nm)/C₆₀ (30 nm)/Bphen (8 nm)/Al (100 nm) show the improvement on performance:short-circuit current J_SC = 9.18 mA/cm², photoelectric conversion efficiency η_p = 1.35% under AM1.5 solar illumination. Compared with η_p of the traditional bulk heterojunction OPV ITO/CuPc(10 nm)/CuPc:C₆₀ (1:1) (20 nm)/C₆₀(30 nm)/Bphen(8 nm)/Al(100 nm), the η_p of the present structure is improved by 25%, which is attributed to the improvement on percolating paths of donor and acceptor molecules across the entire mixing layer, thus increasing the charge collection efficiency. Consequently, the overall device series resistance is reduced and the photoelectric conversion efficiency is enhanced.
Keywords： organic solar cells bulk heterojunction gradient doping