Room Temperature Fabrication of SnO₂ Electrodes Enabling Barrier‐Free Electron Extraction for Efficient Flexible Perovskite Photovoltaics

Abstract

Room temperature-processed electron transport layers (RT-ETLs) demonstrate vast potential to be used in fabricating high-performance flexible perovskite solar cells (PSCs) in an energy-saving manner. However, the RT-ETL normally suffers from inferior crystallinity, mismatched energy level, and high surface trap-state density, which would result in under-optimized interfacial electron extraction and undesirable interfacial charge recombination at ETL/perovskite interface, thus limiting the device performance. Herein, a novel strategy is demonstrated to prepare annealing-free RT-ETL based on precrystalline metal ion-modified SnO 2 nanocrystals, which perfectly optimizes the interfacial energy level alignment between ETL and perovskite layer, achieving nearly zero-barrier charge transfer at the interface. As a result, the charge extraction has been remarkably accelerated and the interfacial charge recombination has been largely suppressed, leading to a ≈26% enhancement in device efficiency. The best-performing flexible PSCs achieve efficiencies up to 19.3%, accompanied by outstanding mechanical strength under repeated bending cycle tests, which, to the best of the knowledge, is one of the highest reported values for the flexible perovskite photovoltaics fabricated with RT-ETLs.

Room-Temperature Detection of Perfluoroisobutyronitrile with SnO2/Ti3C2Tx Gas Sensors

“…A smooth small peak due to the hydroxide or fluoride derivative generated during the etching process can be observed from 15 to 25° in the XRD curve of Ti 3 C 2 T x and removed under the effect of hydrothermal and repeated washing, as depicted in the XRD curve of Ti 3 C 2 T x –SnO 2 . The formation of the SnO 2 (110), (101), and (211) crystal planes are recognized at 27.3, 34.5, and 52.3°, respectively, thereby suggesting the introduction of SnO 2 . The characterization of transmission electron microscopy (TEM) in Figure S3 exhibited that a certain number of NPs ranging from 5 to 20 nm scatter evenly on the surface of Ti 3 C 2 T x nanosheets.…”

“…15 The formation of the SnO 2 (110), (101), and (211) crystal planes are recognized at 27.3, 34.5, and 52.3°, respectively, thereby suggesting the introduction of SnO 2 . 38 The characterization of transmission electron microscopy (TEM) in Figure S3 exhibited that a certain number of NPs ranging from 5 to 20 nm scatter evenly on the surface of Ti 3 C 2 T x nanosheets. High-resolution TEM and selected area electron diffraction (SAED) revealed that exposed crystal planes of these NPs belong to SnO 2 ; these findings are consistent with the XRD results.…”

Embedding SnO2 Thin Shell Protected Ag Nanowires in SnO2 ETL to Enhance the Performance of Perovskite Solar Cells

“…Although significant progress has been achieved, PSCs exhibit some fundamental and crucial issues, especially the energy level mismatching between ETL and perovskite − and the nonradiative recombination at the ETL–perovskite interface that severely degrade the extraction of carriers, − which greatly reduce the PCE and the stability of PSCs . Using silver nanoparticles as reinforcing materials have proven to be an efficient way to solve the above-mentioned problems in very recent years. − Que et al have demonstrated that silver nanoparticles can adjust the energy level of ETL to better match perovskite, increasing the fill factor (FF), and open circuit voltage ( V OC ) of devices .…”

Dip‐Coated SnO2 Electron Transport Layer for Efficient and Stable PbS Quantum Dot Photovoltaics

“…[ 26 ] SnO 2 has been demonstrated as an exceptional ETL candidate for perovskite solar cells, improving both efficiency and stability of the solar cells. [ 27–29 ] Recently, a few efforts attempted on employing SnO 2 ETLs, fabricated by sol–gel and magnetron‐sputtered methods, to PbS CQDSCs, resulting in PCE of around 10%. [ 25,30 ] However, these researches on the CQD PV operational stability are not explored.…”