E-beam evaporated Nb2O5 as an effective electron transport layer for large flexible perovskite solar cells

Abstract: E-beam evaporated Nb2O5 film is directly used as an effective electron transport layer (ETL) for perovskite solar cells without needing any posttreatment. The effect of Nb2O5 thickness on optical and electronic properties of the perovskite layer deposited thereupon are studied in detail. It is found that 60 nm thick Nb2O5 ETL delivers the best photovoltaic performance with PCE as high as 18.59%. In particular, e-beam evaporated Nb2O5 is found to be advantageous in large area flexible perovskite solar cells, with larger area cells showing comparable Jsc and Voc values as smaller area devices, and the PCE loss is mainly caused by increased series resistance leading to reduced FF. With proper cell design to limit the resistance and associated FF loss, it is expected that the large area cells should present respectable FF and PCEs as their smaller area devices.

[1]  Yun-Chorng Chang,et al.  Nickel Oxide Electrode Interlayer in CH3NH3PbI3 Perovskite/PCBM Planar‐Heterojunction Hybrid Solar Cells , 2014, Advanced materials.

[2]  H. Atwater,et al.  Unity-order index change in transparent conducting oxides at visible frequencies. , 2010, Nano letters (Print).

[3]  X. Ren,et al.  Two‐Inch‐Sized Perovskite CH3NH3PbX3 (X = Cl, Br, I) Crystals: Growth and Characterization , 2015, Advanced materials.

[4]  Tsutomu Miyasaka,et al.  Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. , 2009, Journal of the American Chemical Society.

[5]  Wei Chen,et al.  Efficient and stable large-area perovskite solar cells with inorganic charge extraction layers , 2015, Science.

[6]  Qingfeng Dong,et al.  Electron-hole diffusion lengths > 175 μm in solution-grown CH3NH3PbI3 single crystals , 2015, Science.

[7]  Ruixia Yang,et al.  Hysteresis‐Suppressed High‐Efficiency Flexible Perovskite Solar Cells Using Solid‐State Ionic‐Liquids for Effective Electron Transport , 2016, Advanced materials.

[8]  Tsutomu Miyasaka,et al.  Nb2O5 Blocking Layer for High Open-circuit Voltage Perovskite Solar Cells , 2015 .

[9]  Timothy L. Kelly,et al.  Origin of the Thermal Instability in CH3NH3PbI3 Thin Films Deposited on ZnO , 2015 .

[10]  Y. Hu.  Novel Meso‐Superstructured Solar Cells with a High Efficiency Exceeding 12% , 2014, Advanced materials.

[11]  Yong Li,et al.  An innovative design of perovskite solar cells with Al2O3 inserting at ZnO/perovskite interface for improving the performance and stability , 2016 .

[12]  M. Ko,et al.  A tailored TiO2 electron selective layer for high-performance flexible perovskite solar cells via low temperature UV process , 2016 .

[13]  A. Zaban,et al.  Preparation of Nb2O5 Coated TiO2 Nanoporous Electrodes and Their Application in Dye-Sensitized Solar Cells , 2001 .

[14]  X. Ren,et al.  Thinness‐ and Shape‐Controlled Growth for Ultrathin Single‐Crystalline Perovskite Wafers for Mass Production of Superior Photoelectronic Devices , 2016, Advanced materials.

[15]  Jürg Hutter,et al.  Thermal effects on CH3NH3PbI3 perovskite from Ab initio molecular dynamics simulations , 2015 .

[16]  Hongwei Lei,et al.  Low-temperature solution-processed tin oxide as an alternative electron transporting layer for efficient perovskite solar cells. , 2015, Journal of the American Chemical Society.

[17]  R. Rosenberg,et al.  Angle-resolved X-ray photoelectron spectroscopy study of the oxides on Nb surfaces for superconducting r.f. cavity applications , 2003 .