Guanidinium: A Route to Enhanced Carrier Lifetime and Open-Circuit Voltage in Hybrid Perovskite Solar Cells,Nano Letters

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Guanidinium: A Route to Enhanced Carrier Lifetime and Open-Circuit Voltage in Hybrid Perovskite Solar Cells
Nano Letters ( IF 9.6 ) Pub Date : 2016-01-25 00:00:00 , DOI: 10.1021/acs.nanolett.5b04060
Nicholas De Marco ₁ , Huanping Zhou ₁ , Qi Chen ₁ , Pengyu Sun ₁ , Zonghao Liu ₁ , Lei Meng ₁ , En-Ping Yao ₁ , Yongsheng Liu ₁ , Andy Schiffer ₁ , Yang Yang ₁

Affiliation

Hybrid perovskites have shown astonishing power conversion efficiencies owed to their remarkable absorber characteristics including long carrier lifetimes, and a relatively substantial defect tolerance for solution-processed polycrystalline films. However, nonradiative charge carrier recombination at grain boundaries limits open circuit voltages and consequent performance improvements of perovskite solar cells. Here we address such recombination pathways and demonstrate a passivation effect through guanidinium-based additives to achieve extraordinarily enhanced carrier lifetimes and higher obtainable open circuit voltages. Time-resolved photoluminescence measurements yield carrier lifetimes in guanidinium-based films an order of magnitude greater than pure-methylammonium counterparts, giving rise to higher device open circuit voltages and power conversion efficiencies exceeding 17%. A reduction in defect activation energy of over 30% calculated via admittance spectroscopy and confocal fluorescence intensity mapping indicates successful passivation of recombination/trap centers at grain boundaries. We speculate that guanidinium ions serve to suppress formation of iodide vacancies and passivate under-coordinated iodine species at grain boundaries and within the bulk through their hydrogen bonding capability. These results present a simple method for suppressing nonradiative carrier loss in hybrid perovskites to further improve performances toward highly efficient solar cells.

中文翻译：

胍盐：增加混合钙钛矿太阳能电池的载流子寿命和开路电压的途径

杂化钙钛矿由于其出色的吸收剂特性（包括较长的载流子寿命和对溶液加工的多晶膜的相对较大的缺陷容忍度）而显示出惊人的功率转换效率。但是，晶界处的非辐射载流子复合限制了开路电压，并因此改善了钙钛矿太阳能电池的性能。在这里，我们解决了这种重组途径，并证明了通过基于胍的添加剂的钝化效果，以实现极高的载流子寿命和更高的开路电压。时间分辨的光致发光测量可得出基于胍盐的薄膜的载流子寿命比纯甲基铵的载流子寿命大一个数量级，导致更高的器件开路电压和超过17％的功率转换效率。通过导纳光谱和共聚焦荧光强度图谱计算得出的缺陷活化能降低了30％以上，表明晶粒边界处的复合/陷阱中心成功钝化。我们推测胍离子通过其氢键合能力可抑制碘化物空位的形成，并钝化晶界处和内部的配位不足的碘。这些结果提出了一种抑制杂化钙钛矿中非辐射载流子损失的简单方法，以进一步提高针对高效太阳能电池的性能。通过导纳光谱和共聚焦荧光强度图谱计算得出的缺陷活化能降低了30％以上，表明晶粒边界处的复合/陷阱中心成功钝化。我们推测胍离子通过其氢键合能力可抑制碘化物空位的形成，并钝化晶界处和内部的配位不足的碘。这些结果提出了一种抑制杂化钙钛矿中非辐射载流子损失的简单方法，以进一步提高针对高效太阳能电池的性能。通过导纳光谱和共聚焦荧光强度图谱计算得出的缺陷活化能降低了30％以上，表明晶粒边界处的复合/陷阱中心成功钝化。我们推测胍离子通过其氢键合能力可抑制碘化物空位的形成，并钝化晶界处和内部的配位不足的碘。这些结果提出了一种抑制杂化钙钛矿中非辐射载流子损失的简单方法，以进一步提高针对高效太阳能电池的性能。我们推测胍离子通过其氢键合能力可抑制碘化物空位的形成，并钝化晶界处和内部的配位不足的碘。这些结果提出了一种抑制杂化钙钛矿中非辐射载流子损失的简单方法，以进一步提高针对高效太阳能电池的性能。我们推测胍盐离子通过其氢键合能力来抑制碘化物空位的形成，并钝化晶界处和内部的配位不足的碘物种。这些结果提出了一种抑制杂化钙钛矿中非辐射载流子损失的简单方法，以进一步提高针对高效太阳能电池的性能。

更新日期：2016-01-25

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