Triptycene as a Supramolecular Additive in PTB7:PCBM Blends and Its Influence on Photovoltaic Properties.
Triptycene as a Supramolecular Additive in PTB7:PCBM Blends and Its Influence on Photovoltaic Properties.
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DOI：
10.1021/acsami.8b03114
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发表时间：
2018-06
影响因子：
9.5
通讯作者：
Lethy Krishnan Jagadamma;Liam J. McCarron;A. Wiles;Victoria Savikhin;M. Sajjad;Mahdieh Yazdani;V. Rotello;M. Toney;G. Cooke;I. Samuel
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文献类型：
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作者：
Lethy Krishnan Jagadamma;Liam J. McCarron;A. Wiles;Victoria Savikhin;M. Sajjad;Mahdieh Yazdani;V. Rotello;M. Toney;G. Cooke;I. Samuel
在体异质结太阳电池中，添加剂在改变施主和受主分子的形貌和相分离方面起着重要作用。在这里，我们报告三蝶烯（TPC）作为一个小分子添加剂的超分子控制相分离和随之而来的PTB 7供体和富勒烯受体为基础的BHJ聚合物太阳能电池的功率转换效率（PCE）的改善。对于PTB 7：PC61 BM和PTB 7：PC 71 BM共混物，观察到PCE的总体60%的改善。改进的光伏（PV）性能可以归因于三个因素：（a）TPC诱导的与共混物中的供体：受体组分的超分子相互作用，以实现纳米级相分离形态;（B）电荷转移态能量的增加，其降低了电子从供体分子转移到受体分子的驱动力;以及（c）电荷载流子迁移率的增加。使用TPC作为超分子添加剂的效率的改善也已被证明用于其他BHJ共混物，如PBDB-T：PC 71 BM和P3 HT：PCBM，这意味着这种新的添加剂分子的广泛适用性。TPC作为PTB 7：PCBM太阳能电池的添加剂的光稳定性与广泛使用的1，8-二碘辛烷添加剂的光稳定性的比较显示，在AM 1.5G照射34小时后，添加TPC的太阳能电池的PV性能的保持率高出约30%。研究结果表明，利用添加剂促进超分子间的相互作用来改变给体和受体间相分离的长度尺度，是一种非常有前途的方法，有望开发出高效、稳定的有机光致变色材料。
Additives play an important role in modifying the morphology and phase separation of donor and acceptor molecules in bulk heterojunction (BHJ) solar cells. Here, we report triptycene (TPC) as a small-molecule additive for supramolecular control of phase separation and concomitant improvement of the power conversion efficiency (PCE) of PTB7 donor and fullerene acceptor-based BHJ polymer solar cells. An overall 60% improvement in PCE is observed for both PTB7:PC61BM and PTB7:PC71BM blends. The improved photovoltaic (PV) performance can be attributed to three factors: (a) TPC-induced supramolecular interactions with donor:acceptor components in the blends to realize a nanoscale phase-separated morphology; (b) an increase in the charge transfer state energy that lowers the driving force for electron transfer from donor to acceptor molecules; and (c) an increase in the charge carrier mobility. An improvement in efficiency using TPC as a supramolecular additive has also been demonstrated for other BHJ blends such as PBDB-T:PC71BM and P3HT:PCBM, implying the wide applicability of this new additive molecule. A comparison of the photostability of TPC as an additive for PTB7:PCBM solar cells to that of the widely used 1,8-diiodooctane additive shows ∼30% higher retention of PV performance for the TPC-added solar cells after 34 h of AM 1.5G illumination. The results obtained suggest that the approach of using additives that can promote supramolecular interactions to modify the length scale of phase separation between donor and acceptor is very promising and can lead to the development of highly efficient and stable organic photovoltaics.