Bending Durable and Recyclable Mesostructured Perovskite Solar Cells Based on Superaligned ZnO Nanorod Electrode

Abstract

Though high‐quality perovskite films can be achieved under low‐temperature, the efficient charge selective materials, such as the most widely used TiO2, require high‐temperature sintering process, hindering mass production with roll‐to‐roll process by using flexible substrate. Here, a low‐temperature (90 °C) process is developed for preparing superaligned ZnO nanorods (SAZNRs), serving as mesostructured scaffold in direct contact with the perovskite layer. By rational design of the length of the SAZNRs, the perovskite solar cell (PSC), reaches a highest power conversion efficiency of ≈13.8% with largely suppressed hysteresis behavior. More importantly, this nano‐array design demonstrates outstanding mechanical robustness after being incorporated onto the flexible substrate, resulting in a performance preservation of 90% after 1000 bending cycles with a curvature radius of 4 mm. Finite element analysis indicate that the reduction of device performance after bending is ascribed to the cracks occurred in AZO stress concentration layer, which is attested by experiment as well. Besides, the SAZNRs ETM can be reused for fabricating new perovskite solar cells with comparable photovoltaic performance in a time‐saving and scalable manner, paving the way for industrial production of PSCs.

Fabrication of Nickel Oxide Nanopillar Arrays on Flexible Electrodes for Highly Efficient Perovskite Solar Cells

“…The highest stress in the “50-CL” is 3.51 KPa and that in the “50-CL+100-NaPA” is only 2.88 KPa. The deposition of the “100-NaPA” on the “50-CL” allows for the reduction of mechanical stress during bending and gives rise to the homogeneous stress distribution along the bending to effectively prevent the HTL/perovskite interfacial delamination, which supports the experimental results well.…”

“…Semiconductor nanomaterials with controlled morphology and architectures are desirable candidates for hole transporting layers (HTLs) for high-performance perovskite solar cells due to chemical stability, high hole mobility, and facile fabrication. − Among these materials, NiO x has been demonstrated for promising HTLs because of the appropriate energy band related to that of the perovskite and high hole mobility. , Recently, it is of increasing interest to produce flexible PSCs hybridized with NiO x . ,− For example, NiO x nanostructured films were coated on flexible electrodes via a room-temperature solution process, and Najafi et al optimized the triple cation PSCs hybridized with solution-derived NiO x nanoparticles to obtain a high power conversion efficiency (PCE) of 16.6% on flexible substrates. ,,, Despite of the previous efforts, the fabrication of nanostructured NiO x array architectures has been desired in optoelectronics as they can effectively reduce reflection loss, suppress recombination dynamics, − ,− and release stress and strain upon mechanical bending to improve the mechanical stability of optoelectronic flexible devices. ,, However, fabrication of the nanostructured NiO x arrays for hybrid flexible PSCs has been particularly challenging because of no compatibility of polymer-based flexible electrodes to high-temperature (>300 °C) thermal synthesis conditions of NiO x . − …”

To Be Higher and Stronger—Metal Oxide Electron Transport Materials for Perovskite Solar Cells

“…Compared to TiO 2 NR based PSCs, ZnO NR based devices showed higher charge collection rate with a 11.13% efficiency. Our group prepared superaligned ZnO NRs on AZO substrates as meso‐ETL in PSCs and reached a 13.8% efficiency via rational design of the nanorods' length . Specially, the flexible PSCs retained 90% of the original PCE after bending for 1000 cycles with a radius of 4 mm.…”

A Morphological Study of Solvothermally Grown SnO2 Nanostructures for Application in Perovskite Solar Cells

“…It has higher charge mobility compared to TiO 2 and the processing temperatures for preparing ZnO thin films and nanostructures are relatively lower than that of TiO 2 , which is significantly important to the development of flexible PSCs for portable and wearable electronics. The ZnO nanoparticles [ 42 ] and nanorods [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ] are the common nanostructures used for electron-transporting materials in PSCs. However, so far, the reported PCEs of ZnO-based PSCs are lower than that of PSCs with TiO 2 as the ETLs.…”