Simultaneously Modifying Hole Transport Material and Perovskite via a Crown Ether‐Based Semiconductor Toward Efficient and Stable Perovskite Solar Cells

Abstract

In conventional (n‐i‐p) perovskite solar cells (PSCs), spiro‐OMeTAD is the most widely used hole‐transporting material (HTM), which contributes to the current state‐of‐the‐art efficiency. Suffering from the low conductivity, dopants such as LiTFSI (lithium bis(trifluoromethanesulfonyl)imide) and tBP are usually required to achieve excellent hole transport properties in spiro‐OMeTAD. Nevertheless, the hygroscopicity and the migration of Li+ during device operation severely affect the device's stability. To address the aforementioned issue, a 12‐crown‐4‐based organic semiconductor (CDT) is synthesized and applied in PSCs. Notably, CDT is simultaneously doped in spiro‐OMeTAD and perovskite layer through the antisolvent method. In this way, the strong “host‐guest” interaction between crown ether and Li+ effectively inhibits its migration both in the hole transporting layer (HTL) and at the perovskite/HTM interface. Furthermore, the carbazole diphenylamine group in CDT facilitates hole transport, and meanwhile improves the hydrophobicity of the HTL. In addition, CDT added into the perovskite layer is also able to passivate defects by interacting with the undercoordinated Pb2+. In light of the aforementioned advantages, the CDT‐based device shows a high power conversion efficiency approaching 23%, with excellent long‐term stability.

Rhodamine B as an efficient multifunctional passivator for the improvement of perovskite solar cell performance

“…These peak shifts may be due to the O atom of the carboxylic group, the N atom of diethyl amine and the O atom of xanthene sharing the electron with uncoordinated Pb 2+ , respectively. 50–52 These peak shifts further prove the existence of a strong interaction between RhB and MAPbI 3 . To further identify these strong interactions, the XPS spectra of the MAPbI 3 and MAPbI 3 /RhB films were recorded (Fig.…”

2D Polymers with Lead Anchoring Groups Enable Perovskite Solar Cells with Over 24% Efficiency

“…However, designing stable and efficient interface materials for PSCs is still challenging. [22] Polymer interface materials show great promise in passivating surface defects in perovskite films. [23,24] Recently, Yang and coworkers selected a widely used polymer polyvinyl acetate (PVA) containing Lewis base functional groups as the interface material for PSCs, performing excellent defect passivation on the perovskite surface and achieving a PCE of 23.2%.…”

Surface Modulation via Conjugated Bithiophene Ammonium Salt for Efficient Inverted Perovskite Solar Cells

“…The inverted p – i – n perovskite solar cells (PSCs) have gained huge attention due to their sky-rocketed power conversion efficiencies (PCEs) with achieving the certified record of 25.4% . During the past few years, the quality of perovskite films has been largely improved due to the advances made in film processing via compositional and additive engineering, – which partly contributes to the rapid development in PCEs. Moreover, since the interfaces between perovskite and charge transport layers are now considered to be the main limiting factors that hinder the further gain in the device efficiency and operational stability, – interface engineering is generally applied in the highly efficient inverted PSCs.…”