Two novel narrow bandgap π‐conjugated polymers based on naphtho[1,2‐c:5,6‐c′]bis([1,2,5]thiadiazole) (NT) unit are developed, which contain the thiophene or benzodithiophene flanked with alkylthiophene as the electron‐donating segment. Both copolymers exhibit strong aggregations both in solution and as thin films. The resulting copolymers with higher molecular weight show higher photovoltaic performance by virtue of the enhanced short‐circuit current densities and fill factors, which can be attributed to their higher absorptivity and formation of more favorable film morphologies. Polymer solar cells (PSCs) fabricated with the copolymer PNTT achieve remarkable power conversion efficiencies (PCEs) > 11% based on both conventional and inverted structures at the photoactive layer thickness of 280 nm, which is the highest value so far observed from NT‐based copolymers. Of particular interest is that the device performances are insensitive to the thickness of the photoactive layer, for which the PCEs > 10% can be achieved with film thickness ranging from 150 to 660 nm, and the PCE remains >9% at the thickness over 1 µm. These findings demonstrate that these NT‐based copolymers can be promising candidates for the construction of thick film PSCs toward low‐cost roll‐to‐roll processing technology.

中文翻译：

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基于萘并[1,2-c：5,6-c]双[1,2,5]噻二唑共轭聚合物的厚膜聚合物太阳能电池，效率超过11％

两种基于萘并[1,2- c：5,6- c的新型窄带隙π共轭聚合物研制了'] bis（[[1,2,5]噻二唑）（NT）单元，该单元包含噻吩或苯并二噻吩，侧接烷基噻吩作为供电子链段。两种共聚物在溶液和薄膜中均表现出强聚集性。所得的具有较高分子量的共聚物由于增强的短路电流密度和填充因子而具有较高的光伏性能，这可以归因于其较高的吸收率和更有利的膜形态的形成。使用PNTT共聚物制造的聚合物太阳能电池（PSC）在280 nm的光敏层厚度下，无论是传统结构还是倒置结构，其功率转换效率（PCE）均> 11％，这是迄今为止基于NT的最高值共聚物。特别令人感兴趣的是，器件性能对光敏层的厚度不敏感，为此，在150至660 nm的膜厚范围内可实现PCE> 10％，并且在1以上的厚度下PCE保持> 9％微米 这些发现表明，这些基于NT的共聚物可能是向低成本卷对卷加工技术构建厚膜PSC的有希望的候选者。