Carbon nanotube‐silicon (CNT‐Si)‐based heterojunction solar cells (HJSCs) are a promising photovoltaic (PV) system. Herein, few‐layer black phosphorus (FL‐BP) sheets are produced in N‐methyl‐2‐pyrrolidone (NMP) using microwave‐assisted liquid‐phase exfoliation and introduced into the CNTs‐Si‐based HJSCs for the first time. The NMP‐based FL‐BP sheets remain stable after mixing with aqueous CNT dispersion for device fabrication. Due to their unique 2D structure and p‐type dominated conduction, the FL‐BP/NMP incorporated CNT‐Si devices show an impressive improvement in the power conversion efficiency from 7.52% (control CNT‐Si cell) to 9.37%. Our density‐functional theory calculation reveals that lowest unoccupied molecular orbital (LUMO) of FL‐BP is higher in energy than that of single‐walled CNT. Therefore, we observed a reduction in the orbitals localized on FL‐BP upon highest occupied molecular orbital to LUMO transition, which corresponds to an improved charge transport. This study opens a new avenue in utilizing 2D phosphorene nanosheets for next‐generation PVs.

中文翻译：

---

微波剥落少层黑色磷提高单壁碳纳米管-硅异质结太阳能电池的效率

基于碳纳米管-硅（CNT-Si）的异质结太阳能电池（HJSC）是一种很有前途的光伏（PV）系统。在这里，在氮中产生了很少层的黑磷（FL-BP）片甲基-2-吡咯烷酮（NMP）借助微波辅助液相剥离技术首次引入基于CNTs的HJSC中。与用于设备制造的CNT水性分散液混合后，基于NMP的FL-BP片材保持稳定。由于其独特的2D结构和p型主导的传导性，并入FL-BP / NMP的CNT-Si器件的功率转换效率从7.52％（控制CNT-Si电池）显着提高到9.37％。我们的密度泛函理论计算表明，FL-BP的最低未占据分子轨道（LUMO）的能量高于单壁CNT的能量。因此，我们观察到当分子占据最高分子轨道至LUMO跃迁时，位于FL-BP上的轨道减少，这对应于改善的电荷传输。