Dion-Jacobson phase two-dimensional (DJ 2D) perovskites, recently attracting considerable interests, exhibit excellent environmental stability and structural tunability, but their solar cells still offer unsatisfactory power conversion efficiencies (PCEs). Herein, we develop DJ 2D perovskites employing formamidinium (FA⁺) as a ternary cation in the perovskite cages ((PDA)(FA)_x(MA)_3-xPb₄I₁₃, x=0, 0.15, 0.3 and 0.6, PDA=1,3-propanediammonium) for highly efficient and stable perovskite solar cells (PSCs). We found that the DJ 2D perovskite with a 10% FA⁺ fraction presents improved crystallinity, preferred vertical orientation, and longer charge carrier lifetime compared to that without FA⁺ doping. As a result, the FA-doped DJ 2D PSCs exhibit a champion PCE of 14.74% with superior device stability. The unencapsulated devices sustain over 92% of its initial PCE after storage at a constant relative humidity (RH) of 65% for 6000 h, 90% by heat at 85 °C in air for 800 h, and 94% under 1-sun illumination for 5000 h. These findings demonstrate that the incorporation of FA cation into the DJ 2D perovskite is a promising strategy to develop highly efficient and stable DJ 2D PSCs.

Dion-Jacobson相二维（DJ 2D）钙钛矿最近引起了广泛的关注，具有出色的环境稳定性和结构可调性，但它们的太阳能电池仍无法提供令人满意的功率转换效率（PCE）。在本文中，我们开发了在钙钛矿笼中使用甲ami（FA ⁺）作为三元阳离子的DJ 2D钙钛矿（（PDA）（FA）_x（MA）_{3- x} Pb ₄ I ₁₃，x = 0，0.15，0.3和0.6， PDA = 1,3-丙二铵）用于高效稳定的钙钛矿太阳能电池（PSC）。我们发现DJ 2D钙钛矿具有10％FA ⁺与未掺杂FA ^+的相比，该组分具有更高的结晶度，更好的垂直取向和更长的载流子寿命。结果，掺有FA的DJ 2D PSC表现出14.74％的PCE冠军，并且具有出色的设备稳定性。未封装的器件在65％的恒定相对湿度（RH）下存储6000小时，在85°C的空气中加热800％的热量和90％在1阳光下的恒定相对湿度（RH）下存储后，其初始PCE保持92％以上。持续5000小时 这些发现表明，将FA阳离子掺入DJ 2D钙钛矿中是开发高效且稳定的DJ 2D PSC的有前途的策略。