ACS Appl Mater Interfaces. 2018 Jul 11;10(27):23254-23262. doi: 10.1021/acsami.8b05956. Epub 2018 Jun 27.
Recently, perovskite solar cells (PSCs) have emerged as an excellent photovoltaic device owing to the outstanding power conversion efficiency (PCE). Nevertheless, device instability remains a critical issue in this field. To overcome device instability without deteriorating PCE, dopant-free hole transporting materials (HTMs) are needed to separate the air-sensitive perovskite layer from extrinsic factors, which induce its degradation. Herein, we developed novel conjugate polymers of benzo[1,2- b:4,5- b']dithiophene (BDT) and 4,4-difluoro-4-bora-3 a,4 a-diaza- s-indacene (BODIPY) for use as HTMs without dopants. The pBDT-BODIPY polymer allows individual "dialing" of the highest occupied molecular orbital (HOMO) or lowest unoccupied molecular orbital (LUMO) levels with small modifications to the molecular structure, enabling study of the impact of the frontier molecular orbital on PSC performance. Different alkyl chains on BDT can minutely adjust the HOMO level, and meso-substituents on BODIPYs can selectively set the LUMO level of the resulting polymers. Application of BODIPY-containing polymer into the perovskite solar cell as an HTM leads to a high PCE value (16.02%) and exceptional solar cell stability shown by the fact that over 80% of its original PCE value was maintained after 10 days under ambient air conditions.
最近，由于其出色的功率转换效率（PCE），钙钛矿太阳能电池（PSCs）作为一种优秀的光伏器件而崭露头角。然而，器件不稳定性仍然是该领域的一个关键问题。为了在不降低 PCE 的情况下克服器件不稳定性，需要使用无掺杂空穴传输材料（HTM）将对空气敏感的钙钛矿层与导致其降解的外在因素隔离开来。在此，我们开发了新型的苯并[1,2-b:4,5-b']二噻吩（BDT）和 4,4-二氟-4-硼-3a,4a-二氮杂-s-茚（BODIPY）共轭聚合物，用作无掺杂剂的 HTM。pBDT-BODIPY 聚合物允许通过对分子结构进行微小修改，单独“调整”最高占据分子轨道（HOMO）或最低未占据分子轨道（LUMO）能级，从而研究前沿分子轨道对 PSC 性能的影响。BDT 上的不同烷基链可以细微调整 HOMO 能级，而 BODIPYs 上的中位取代基可以选择性地设置所得聚合物的 LUMO 能级。将含 BODIPY 的聚合物应用于钙钛矿太阳能电池作为 HTM，可获得高 PCE 值（16.02%）和出色的太阳能电池稳定性，在环境空气条件下放置 10 天后，其原始 PCE 值的 80%以上仍得以保持。
