Abstract The addition of a tiny amount of fluorescent organic material N, N′-di (naphtha-1-yl)-N, N′-diphenyl-benzidine (NPB) into polymeric hole transport layer (HTL) is shown to yield a significant enhancement in down-conversion of ultraviolet (UV) light into visible light. As a result, NPB incorporated HTL based devices exhibit enhancement in power conversion efficiency (PCE) of 18.2% compared to 15.1% for pristine devices. This work demonstrated that fluorescent down-conversion of UV light based on doped HTLs is a novel and effective approach for enhanced performance of perovskite solar cells (PSCs). In addition, the incorporated fluorescent material NPB provides a favorable energetic alignment at the interface for low voltage loss. These results are further supported by time-resolved photoluminescence (TRPL) measurements that are performed on perovskite layers deposited on top of NPB doped Poly (triaryl amine) (PTAA), which shows an improvement in lifetime of the charge carriers with increasing concentration of NPB. An increase in the lifetime of the charge carriers is observed on the perovskite layer that is deposited on top of 2.5 wt% NPB doped PTAA layer. The lifetime enhancement is due to additional charge carriers that are generated from the conversion of high energy photons to low energy photons. These additional charge carriers that are generated in HTL occupy the charge transport states after filling the trap states in the perovskite layer and hence the lifetime of the charge carriers increases. The TRPL lifetime decreases with further increase in the NPB concentration more than 2.5 wt% due to efficient charge carrier extraction.

中文翻译：

---

高效钙钛矿太阳能电池的界面工程和紫外光下转换

摘要 将少量荧光有机材料 N, N'-di (naphtha-1-yl)-N, N'-diphenyl-benzidine (NPB) 添加到聚合物空穴传输层 (HTL) 中显示出显着的增强将紫外线 (UV) 光下转换为可见光。因此，与原始设备的 15.1% 相比，包含 NPB 的基于 HTL 的设备的功率转换效率 (PCE) 提高了 18.2%。这项工作表明，基于掺杂 HTL 的紫外光荧光下转换是提高钙钛矿太阳能电池 (PSC) 性能的一种新颖且有效的方法。此外，掺入的荧光材料 NPB 在界面处提供了有利的能量排列，以实现低电压损失。这些结果得到了时间分辨光致发光 (TRPL) 测量的进一步支持，这些测量是在沉积在 NPB 掺杂的聚（三芳基胺）（PTAA）顶部的钙钛矿层上进行的，这表明随着 NPB 浓度的增加，电荷载流子的寿命有所改善. 在沉积在 2.5 wt% NPB 掺杂 PTAA 层顶部的钙钛矿层上观察到电荷载流子的寿命增加。寿命增强是由于高能光子向低能光子的转换产生的额外电荷载流子。这些在 HTL 中产生的额外电荷载流子在填充钙钛矿层中的陷阱态后占据电荷传输态，因此电荷载流子的寿命增加。