A new donor–acceptor-type all-conjugated block copolymer (BCP), P(NDI-DBDT)-block-P(NDI-2T), is synthesized through the coupling of a naphthalene diimide (NDI)-bithiophene (2T) segment-based polymer (P1) and an NDI-dithienylbenzodithiophene (DBDT) segment-based polymer (P2). P1 has a prevailing backbone for NDI-based polymer acceptors, while P2 is modified to contain a p-type DBDT moiety to facilitate miscibility with the DBDT-based polymer donors. When adding 1 wt% BCP (the optimized blending amount) into the PBDB-T:N2200 blend that possesses similar constituent units to the BCP, the derived device can deliver an enhanced power conversion efficiency (PCE) of 7.07%, outperforming the control device (with a PCE of 5.71%). This improvement is found to arise from the more optimized bulk-heterojunction (BHJ) morphology as a result of facilitated intermixing between the photoactive components. This leads to reduced charge recombination and potential loss for the device. Moreover, the more optimized BHJ morphology endows the device with improved thermal robustness. It demonstrates longer T₈₀ lifetimes when stored under constant thermal conditions at high temperatures. Consequently, the device lifetime can be extended to ∼2 years when stored under inert conditions at 50 °C. These results demonstrate that the rationally designed all-conjugated BCP can effectively modulate the BHJ morphology of an all-polymer blend to simultaneously enhance its photovoltaic performance and stability.

中文翻译：

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萘二亚胺基全共轭嵌段共聚物作为有效的增容剂提高全聚合物太阳能电池的性能和热稳定性

一种新型供体-受体型全共轭嵌段共聚物（BCP），P(NDI-DBDT)-嵌段-P(NDI-2T)，是通过萘二亚胺 (NDI)-联噻吩 (2T) 链段聚合物 (P1) 和 NDI-二噻吩基苯并二噻吩 (DBDT) 链段聚合物 (P2) 偶联合成的。P1 具有基于 NDI 的聚合物受体的主要骨架，而 P2 被修饰为包含 p 型 DBDT 部分，以促进与基于 DBDT 的聚合物供体的混溶。当在与 BCP 具有相似组成单元的 PBDB-T:N2200 混合物中添加 1 wt% BCP（优化混合量）时，衍生器件可提供 7.07% 的增强的功率转换效率 (PCE)，优于控制器件（PCE 为 5.71%）。发现这种改进源于更优化的体异质结 (BHJ) 形态，这是光活性组分之间促进混合的结果。这导致减少的电荷复合和设备的潜在损失。此外，更优化的 BHJ 形态使器件具有更高的热稳健性。它展示了更长的时间在高温恒温条件下储存时的T ₈₀寿命。因此，当在 50°C 的惰性条件下储存时，器件的寿命可以延长至约 2 年。这些结果表明，合理设计的全共轭 BCP 可以有效调节全聚合物共混物的 BHJ 形态，同时提高其光伏性能和稳定性。