A single-phase brookite TiO2 nanoparticle bridge enhances the stability of perovskite solar cells
A single-phase brookite TiO2 nanoparticle bridge enhances the stability of perovskite solar cells
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DOI：
10.1039/c9se01133a
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发表时间：
2020-03
影响因子：
5.6
通讯作者：
M. Shahiduzzaman;A. Kulkarni;S. Visal;Liangle Wang;Masahiro Nakano;Makoto Karakawa;Kohshin Takahashi-Kohshin-Takahas
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文献类型：
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作者：
M. Shahiduzzaman;A. Kulkarni;S. Visal;Liangle Wang;Masahiro Nakano;Makoto Karakawa;Kohshin Takahashi-Kohshin-Takahas
二氧化钛（TiO2）基平面钙钛矿太阳能电池（PSCs）长期稳定性差，在器件特性曲线上表现出滞后行为。除了钙钛矿优异的体积特性外，其性能和稳定性也高度依赖于TiO2致密层（CL）的导带能量、电导率和电子阱状态。在这项研究中，利用水溶性钛配合物，通过水热法合成了单相板钛矿（BK） TiO2纳米颗粒（NPs），并将其作为钙钛矿和TiO2 CL之间的桥梁。扫描电镜（SEM）、光致发光（PL）和阻抗谱结果分别显示，这导致了均匀的大钙钛矿晶粒生长，结晶度增强，陷阱/缺陷位点和界面重组显著减少。所得的PSCs显示出高度可重复的功率转换效率（pce），最高可达~ 18.2% (vs. ~ 15%)，在最大功率点跟踪（MPPT）的连续光照（1个太阳）下，与仅基于TiO2 CL的平面器件相比，PSCs的稳定性能为18%。据我们所知，这是迄今为止报道的基于brookite NP的psc的最佳光稳定性数据。在此基础上，提出了进一步提高平面PSCs稳定性的方向。
Titanium dioxide (TiO2) based planar perovskite solar cells (PSCs) suffer from poor long-term stability and show hysteretic behaviour in the device characteristic curve. In addition to the exceptional bulk properties of the perovskite, the performance and stability are also highly dependent on the conduction band energy, conductivity, and electronic trap states of the TiO2 compact layer (CL). In this work, single-phase brookite (BK) TiO2 nanoparticles (NPs), synthesized via a hydrothermal method using a water-soluble titanium complex, are incorporated as a bridge between the perovskite and TiO2 CL. This resulted in uniform large perovskite grain growth with enhanced crystallinity, significant reduction in trap/defect sites and interfacial recombination as revealed by scanning electron microscopy (SEM), photoluminescence (PL), and impedance spectroscopy results, respectively. The resulting PSCs show highly reproducible power conversion efficiencies (PCEs) up to ∼18.2% (vs. ∼15%) with a stable performance of 18% under continuous light illumination (1 sun) at the maximum power point tracking (MPPT) in contrast to only TiO2 CL based planar devices. To the best of our knowledge, this is so far the best photo-stability data reported for brookite NP based PSCs. Based on our present study, at the end we provide further direction to enhance the stability of planar PSCs.