Employing 2D‐Perovskite as an Electron Blocking Layer in Highly Efficient (18.5%) Perovskite Solar Cells with Printable Low Temperature Carbon Electrode

Abstract

Interface engineering and passivating contacts are key enablers to reach the highest efficiencies in photovoltaic devices. While printed carbon–graphite back electrodes for hole‐transporting material (HTM)‐free perovskite solar cells (PSCs) are appealing for fast commercialization of PSCs due to low processing costs and extraordinary stability, this device architecture so far suffers from severe performance losses at the back electrode interface. Herein, a 2D perovskite passivation layer as an electron blocking layer (EBL) at this interface to substantially reduce interfacial recombination losses is introduced. The formation of the 2D perovskite EBL is confirmed through X‐ray diffraction, photoemission spectroscopy, and an advanced spectrally resolved photoluminescence microscopy mapping technique. Reduced losses that lead to an enhanced fill factor and VOC are quantified by electrochemical impedance spectroscopy and JSC–VOC measurements. This enables reaching one of the highest reported efficiencies of 18.5% for HTM‐free PSCs using 2D perovskite as an EBL with a significantly improved device stability.

Ink Engineering in Blade‐Coating Large‐Area Perovskite Solar Cells

“…Reproduced with permission. [133] Copyright 2022, Wiley-VCH. flexible and rigid PSCs show good photovoltaic performance and excellent operational, moisture, or mechanical stabilities, emphasizing the importance of ink engineering in bladecoated PSCs.…”

“…The HTM‐free PSCs with carbon electrode and 2D perovskite layer exhibited a high PCE of 18.5% (active area 0.1 cm 2 ), which is among the highest efficiencies of HTM‐free carbon‐based PSCs, and the unencapsulated device retained 82% of its initial efficiency after 500 h of tracking under maximum power point. [ 133 ]…”

“…e) Energy band illustration of 3D perovskite without (left) and with (right) 2D perovskite layer. Reproduced with permission [133]. Copyright 2022, Wiley-VCH.…”

Counter electrodes for perovskite solar cells: materials, interfaces and device stability

“…117 Kim and coworkers developed a two dimensional perovskite electron blocking layer in hole-conductor free devices in order to reduce the charge losses at interfaces, which enables a promising PCE of 18.5%. 118…”

Introduction of cadmium chloride additive to improve the performance and stability of perovskite solar cells

“…Typically, according to the direction of the photocurrent, the fundamental architecture of HPSCs can be categorized into conventional (n–i–p) and inverted (p–i–n) architectures. 9,10 It's worth mentioning that the perovskite material is the heart of an HPSC device, and its overall quality determines how well it performs. The power conversion efficiency (PCE), hysteresis, and long-term stability of HPSCs are all influenced by the morphology, crystalline nature, and surface covering of the perovskite film.…”