The rational design of dopant-free organic hole-transporting layer (HTL) materials is still a challenge for realizing high-efficient and stable p-i-n planar perovskite solar cells (pero-SCs). Here, we synthesized two π-conjugated small-molecule HTL materials through tailoring the backbone and conjugated side chain to carefully control molecular conformation. The resultant BDT-TPA-sTh containing a planar fused benzo[1,2-b:4,5-b′]dithiophene (BDT) core and a conjugated thiophene side chain showed the planar conformation. X-ray crystallography showed a favorable stacking model in solid states under the parallel-displaced π-π and additional S-π weak-bond supramolecular interactions, thus achieving an obviously increased hole mobility without dopants. As an HTL material in p-i-n planar pero-SCs, the marginal solubility of BDT-TPA-sTh enabled inverse diffusion into the perovskite precursor solution for assisting the subsequent perovskite film growth and passivating the uncoordinated Pb²⁺ ion defects. As a result, the planar p-i-n pero-SCs exhibited a champion power conversion efficiency (PCE) of 20.5% and enhanced moisture stability. Importantly, the BDT-TPA-sTh HTL material also showed weak thickness-photovoltaic dependence, and the pero-SCs with blade-coated BDT-TPA-sTh as a HTL achieved a 15.30% PCE for the 1-cm² modularized device. This HTL material design strategy is expected to pave the way toward high-performance, dopant-free and printing large-area planar p-i-n pero-SCs.

对于实现高效且稳定的针状平面钙钛矿太阳能电池（pero-SCs），无掺杂有机空穴传输层（HTL）材料的合理设计仍然是一个挑战。在这里，我们通过定制主链和共轭侧链来精心控制分子构象，从而合成了两种π共轭小分子HTL材料。所得的BDT-TPA- s Th含有平面稠合的苯并[1,2- b：4,5- b']二噻吩（BDT）核心和共轭噻吩侧链显示平面构象。X射线晶体学显示在平行位移的π-π和其他S-π弱键超分子相互作用下，固态有良好的堆积模型，因此在没有掺杂剂的情况下，空穴迁移率明显增加。作为销平面pero-SC中的HTL材料，BDT-TPA-sTh的边际溶解度使之逆扩散到钙钛矿前体溶液中，从而有助于随后的钙钛矿膜生长和钝化未配位的Pb ²⁺离子缺陷。结果，平面针脚pero-SC表现出20.5％的最佳功率转换效率（PCE）和增强的湿气稳定性。重要的是，BDT-TPA- sTh HTL材料还显示出较弱的厚度-光伏依赖性，并且带有叶片涂层BDT-TPA- s Th作为HTL的pero-SC对1 cm ²模块化设备的PCE达到15.30％。这种HTL材料设计策略有望为高性能，无掺杂剂和印刷大面积平面引脚pero-SC铺平道路。