We investigated the charge-transfer reactions of solar cells including a quaterthiophene copolymer with naphtho-bis-thiadiazole (PNTz4T) and naphtho-bis-oxadiazole (PNOz4T) using constrained density functional theory (CDFT). According to our calculations, the high electron-transfer rate results in a highly efficient solar cell, and the stable charge-transfer state results in low energy loss. Our computations imply that the following three factors are crucial to improve the performance of semiconducting polymers: (i) large structural changes following charge-transfer, (ii) narrow band gap, and (iii) spatially delocalized lowest unoccupied molecular orbital (LUMO) of the ground state.

我们使用约束密度泛函理论（CDFT）研究了包括季噻吩共聚物与萘双-噻二唑（PNTz4T）和萘双-恶二唑（PNOz4T）在内的太阳能电池的电荷转移反应。根据我们的计算，高电子传输速率可导致高效率的太阳能电池，而稳定的电荷传输状态可导致低的能量损耗。我们的计算表明，以下三个因素对于提高半导体聚合物的性能至关重要：（i）电荷转移后发生大的结构变化；（ii）窄带隙；（iii）空间离域的最低未占据分子轨道（LUMO）基态。