The solid solution phenomenon in the amorphous PCDTBT:PC₇₁BM blend was investigated. It has been disclosed that the PCDTBT:PC₇₁BM blend with less than 20% PC₇₁BM may form a kind of solid solution structure, which demonstrates a deeper HOMO level, a higher hole mobility, more free charges and less trap density than those of the pure PCDTBT film. It may well explain why the typical PCDTBT:PC₇₁BM bulk heterojunction solar cells require higher PC₇₁BM ratio to achieve a high power conversion efficiency. In that case, a portion of PC₇₁BM is well intermixed with PCDTBT to form a solid solution phase and others form a pure PC₇₁BM phase. It is the PCDTBT:PC₇₁BM solid solution but not the pure PCDTBT to serve as the donor phases and to form interpenetrating networks with PC₇₁BM phases. The PCDTBT:PC₇₁BM solid solution phases favor to increase the V_OC and enhance the charge collection leading to a high photovoltaic performance for the PCDTBT:PC₇₁BM bulk heterojunction solar cells.

研究了非晶态PCDTBT：PC ₇₁ BM共混物中的固溶现象。已经公开的是，PCDTBT：PC ₇₁ BM共混物具有小于20％的PC ₇₁ BM可以形成一种固溶体结构的，这表明一个更深的HOMO能级，较高的空穴迁移率，更自由电荷和更少陷阱密度比那些纯PCDTBT膜。这可以很好地解释为什么典型的PCDTBT：PC ₇₁ BM本体异质结太阳能电池需要更高的PC ₇₁ BM比才能实现高功率转换效率。在这种情况下，一部分PC ₇₁ BM与PCDTBT充分混合，形成固溶相，而另一部分则形成纯PC ₇₁ BM相。这是PCDTBT：PC₇₁ BM固溶体而非纯PCDTBT用作施主相并与PC ₇₁ BM相形成互穿网络。PCDTBT：PC ₇₁ BM固溶体相有利于增加V _OC并增强电荷收集，从而为PCDTBT：PC ₇₁ BM本体异质结太阳能电池提供了高光伏性能。