Improved charge carrier dynamics in polymer/perovskite nanocrystal based hybrid ternary solar cells.
Improved charge carrier dynamics in polymer/perovskite nanocrystal based hybrid ternary solar cells.
复制标题
DOI：
10.1039/c8cp03743d
复制
发表时间：
2018-09
期刊：
影响因子：
--
通讯作者：
R. Soltani;Bianka M. D. Puscher;A. Katbab;Ievgen Levchuk;Negar Kazerouni;Nicola Gasparini;N. Camaioni;A. Osvet;M. Batentschuk;R. Fink;D. Guldi;T. Ameri
中科院分区：
文献类型：
--
作者：
R. Soltani;Bianka M. D. Puscher;A. Katbab;Ievgen Levchuk;Negar Kazerouni;Nicola Gasparini;N. Camaioni;A. Osvet;M. Batentschuk;R. Fink;D. Guldi;T. Ameri
本文报道了一种新型的三元混合太阳能电池，该电池由钙钛矿纳米晶(NCS)和有机基质的互补吸收轮廓组成。特别地，基于pDP5T-2电子供体聚合物和[6，6]-苯基-C61-丁酸甲酯(PC61BM)受体，在不同负载量下，在体相异质结有机太阳能电池中实现了NH_2CH[双键，长度为m-短划线]NH_2PbI_3(FAPbI_3)钙钛矿型NCS，并用不同的光电表征方法对所制备的复合光伏电池进行了深入的研究。电流-电压测量和线性升压光生载流子提取(Photo-CELIV)研究表明，在复合太阳能电池的光活性层中掺入钙钛矿型纳米碳管后，其电荷产生和电荷传输性能得到了改善。与有机参照物相比，含5%钙钛矿型NCS的混合太阳能电池的功率转换效率(PCE)提高了10%，这主要是由于增加了光捕获量和增加了短路电流密度(JSC)。然而，结果表明，引入较高的钙钛矿含量会在三元器件中诱导双分子复合和陷阱辅助复合。我们利用飞秒泵浦探测暂态吸收光谱(FS-TAS)对电荷转移/输运机制进行了全面的暂态吸收研究。FS-TAS测量表明，由于钙钛矿型纳米碳管的引入，导致了较慢的载流子复合速率。结果表明，DPP将单重态激发态的电子注入到钙钛矿型NCS中，导致了所需的级联载流子转移。在三元共混物中，少量的FAPbI3 NCS为电荷分离态提供了一条额外的途径，尽管NCS加速了DPP单重态的布居减少，但却略微减缓了DPP和PC61BM之间的电荷分离过程。有趣的是，损耗过程减慢了；这一影响更重要，因此解释了太阳能电池效率的提高。
Here, brand new ternary hybrid solar cells comprising perovskite nanocrystals (NCs) with a complementary absorption profile of the organic host matrix are reported. In particular, NH2CH[double bond, length as m-dash]NH2PbI3 (FAPbI3) perovskite NCs are implemented in bulk heterojunction organic solar cells based on the pDPP5T-2 electron donating polymer and a [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) acceptor at various loading amounts and the fabricated hybrid photovoltaics are thoroughly studied by employing different optoelectrical characterization methods. Current-voltage measurements and photoinduced charge carrier extraction by linear increasing voltage (photo-CELIV) reveal improved charge generation and charge transport properties upon incorporation of perovskite NCs into the photo-active layer of the hybrid solar cell. The power conversion efficiency (PCE) of the hybrid solar cell comprising 5% perovskite NCs is 10% enhanced compared to the organic reference, mainly due to the enlarged light harvesting and increased short circuit current density (Jsc). However, results suggest that introducing a higher amount of perovskite content induces bimolecular and trap-assisted recombination in the ternary devices. We perform a comprehensive transient absorption study of the charge transfer/transport mechanisms by employing femto-second pump-probe transient absorption spectroscopy (fs-TAS). fs-TAS measurements demonstrate a slower charge carrier recombination rate due to the introduction of perovskite NCs into the photoactive layer. Results reveal that DPP injects electrons from the singlet excited state into the perovskite NCs, which causes the desired cascading charge carrier transfer. In ternary blends, a small amount of FAPbI3 NCs provides an additional pathway in favor of the charge-separated state via the NCs, which, despite accelerating the depopulation of DPP's singlet excited state slightly slows down the charge-separation process between DPP and PC61BM. Interestingly, the loss processes are slowed down; an effect that is more important and, hence, explains the improved solar cell efficiency.