Two poly(naphthalene diimide)s (PNDIs) have been developed using p-phenylene ethynylene-based comonomers with either thiophene side chains (P(NDI-BT)) or bithiophene side chains (P(NDI-BBT)), and the effects of the length of conjugated side chains on electrochemical, optical, and morphological properties were investigated. Both polymers showed additional vibronic peaks due to the interchain π-π* transition, and a high absorption coefficient (α) of the order of 10⁵ cm⁻¹ was observed. P(NDI-BBT) gave higher α with narrower optical energy band gaps and lower lying the lowest unoccupied molecular orbital (LUMO) energy levels compared to those in P(NDI-BT). Interestingly, lower crystallinity was observed in P(NDI-BBT) than P(NDI-BT), which is the opposite of trends shown for reported polymers with conjugated side chains. Their charge carrier mobilities and photovoltaic properties were also investigated, and provide insight of designing NDI based n-type polymer semiconductors with conjugated side chians.

两种聚萘二亚胺 (PNDI) 已使用基于对苯撑乙炔基的共聚单体与噻吩侧链 (P(NDI-BT)) 或联噻吩侧链 (P(NDI-BBT)) 开发，以及其影响研究了共轭侧链长度对电化学、光学和形态学性质的影响。由于链间 π-π* 跃迁和 10 ⁵ cm ^-1数量级的高吸收系数 (α)，两种聚合物都显示出额外的振动峰被观测到。与 P(NDI-BT) 相比，P(NDI-BBT) 产生更高的 α，具有更窄的光学能带隙和更低的最低未占分子轨道 (LUMO) 能级。有趣的是，在 P(NDI-BBT) 中观察到的结晶度低于 P(NDI-BT)，这与已报道的具有共轭侧链的聚合物所显示的趋势相反。还研究了它们的电荷载流子迁移率和光伏特性，并提供了设计具有共轭侧链的基于 NDI 的n型聚合物半导体的见解。