Abdi-Jalebi Mojtaba, Ibrahim Dar M, Senanayak Satyaprasad P, Sadhanala Aditya, Andaji-Garmaroudi Zahra, Pazos-Outón Luis M, Richter Johannes M, Pearson Andrew J, Sirringhaus Henning, Grätzel Michael, Friend Richard H
Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland.
Sci Adv. 2019 Feb 15;5(2):eaav2012. doi: 10.1126/sciadv.aav2012. eCollection 2019 Feb.
One source of instability in perovskite solar cells (PSCs) is interfacial defects, particularly those that exist between the perovskite and the hole transport layer (HTL). We demonstrate that thermally evaporated dopant-free tetracene (120 nm) on top of the perovskite layer, capped with a lithium-doped Spiro-OMeTAD layer (200 nm) and top gold electrode, offers an excellent hole-extracting stack with minimal interfacial defect levels. For a perovskite layer interfaced between these graded HTLs and a mesoporous TiO electron-extracting layer, its photoluminescence yield reaches 15% compared to 5% for the perovskite layer interfaced between TiO and Spiro-OMeTAD alone. For PSCs with graded HTL structure, we demonstrate efficiency of up to 21.6% and an extended power output of over 550 hours of continuous illumination at AM1.5G, retaining more than 90% of the initial performance and thus validating our approach. Our findings represent a breakthrough in the construction of stable PSCs with minimized nonradiative losses.
钙钛矿太阳能电池（PSC）中不稳定性的一个来源是界面缺陷，尤其是钙钛矿与空穴传输层（HTL）之间存在的那些缺陷。我们证明，在钙钛矿层顶部热蒸发无掺杂剂的并四苯（120纳米），其上覆盖锂掺杂的Spiro-OMeTAD层（200纳米）和顶部金电极，可提供具有最小界面缺陷水平的优异空穴提取堆叠结构。对于介于这些渐变HTL和介孔TiO电子提取层之间的钙钛矿层，其光致发光产率达到15%，而单独介于TiO和Spiro-OMeTAD之间的钙钛矿层的光致发光产率为5%。对于具有渐变HTL结构的PSC，我们证明其效率高达21.6%，在AM1.5G条件下连续光照超过550小时的扩展功率输出，保留了超过90%的初始性能，从而验证了我们的方法。我们的发现代表了在构建具有最小化非辐射损失的稳定PSC方面的一项突破。
