Achieving 20% Efficiency for Low‐Temperature‐Processed Inverted Perovskite Solar Cells

Abstract

Low-temperature-processed inverted perovskite solar cells (PVSCs) attract increasing attention because they can be fabricated on both rigid and flexible substrates. For this devices, holetransporting layers (HTLs) play an important role in achieving efficient and stable inverted PVSCs by adjusting the anodic work function, hole extraction, and interfacial charge recombination. Here, we report the use of a low-temperature (≤ 150 °C) solution-processed ultrathin film of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(4-secbutylphenyl) diphenylamine)] (TFB) as an HTL in one-stepprocessed CH 3 NH 3 PbI 3 (MAPbI 3 )-based inverted PVSCs. The fabricated device exhibits power conversion efficiency (PCE) as high as 20.2% when measured under AM 1.5 G illumination. This PCE makes them one of the MAPbI 3 -based inverted PVSCs that have the highest efficiency reported to date. Moreover, this inverted PVSC also shows good stability, which can retain 90% of its original efficiency after 30 days of storage in ambient air.

Simplified Compact Perovskite Solar Cells with Efficiency of 19.6% via Interface Engineering

“…To the best of our knowledge, this is the highest efficiency among the 3L‐SPSCs. Beyond that, both the efficiency and V oc are comparable to those from the best 4L‐SPSCs or even conventional 5L‐PSCs ever reported …”

“…The designed CPSCs are promising to work as competitively as conventional 5L‐PSCs ever reported, although the amount of charge transport materials contained in CPSCs is much less. Firstly, we have successfully demonstrated a prototype of high‐performance CPSCs (PCE> 15%) that are free of independent CTLs.…”

“…Beyond that, both the efficiency and V oc are comparable to those from the best 4L-SPSCs or even conventional 5L-PSCs ever reported. [16,25,29,30] Figure 1 illustrates the fabrication process of CPSC in comparison with conventional 5L-PSC where both HTL and ETL are within the device. For CPSC, the effective electrode functionalized by an organic monolayer (ML-ITO) of 4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl) benzenamine] (TAPC) was used directly for the deposition of CH 3 NH 3 PbI 3-x Cl x (MAPbI 3-x Cl x ) based on our previous report.…”

High‐Performance Flexible Perovskite Solar Cells via Precise Control of Electron Transport Layer

“…Nevertheless, the grain size of perovskite films on flexible substrate is sacrificed slightly, reduced from 970 to 910 nm ( Figure S1, Supporting Information). [36,37] Regarding the X-ray diffraction (XRD) patterns ( Figure S2a, Supporting Information), as compared with perovskite film on Glass/ITO/SnO 2 , the one deposited on flexible PEN/ITO/SnO 2 shows reduced crystallinity and same peak positions despite the apparent peak derived from PEN/ITO ( Figure S3, Supporting Information), indicating the same crystal structure and composition of perovskite. The SnO 2 film with pinholes could lead to the direct contact between the perovskite precursor and ITO layer, thus it may induce more nucleation sites during the crystallization and growth of perovskite layer, which is detrimental to the grain size of perovskite.…”

Polyfluorene Copolymers as High‐Performance Hole‐Transport Materials for Inverted Perovskite Solar Cells

“…Polyfluorenes with high hole mobilities have been previously used as interlayers to improve hole injection in light‐emitting diodes and field‐effect transistors . In contrast, the application of polyfluorenes as HTMs for construction of PSCs was scarcely reported . Early in 2014, Zhu et al for the first time investigated the use of polyfluorenes as HTMs for the preparation of normal architecture PSCs .…”