Zuo Lijian, Guo Hexia, deQuilettes Dane W, Jariwala Sarthak, De Marco Nicholas, Dong Shiqi, DeBlock Ryan, Ginger David S, Dunn Bruce, Wang Mingkui, Yang Yang
Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Sci Adv. 2017 Aug 23;3(8):e1700106. doi: 10.1126/sciadv.1700106. eCollection 2017 Aug.
The solution processing of polycrystalline perovskite films introduces trap states that can adversely affect their optoelectronic properties. Motivated by the use of small-molecule surfactants to improve the optoelectronic performance of perovskites, we demonstrate the use of polymers with coordinating groups to improve the performance of solution-processed semiconductor films. The use of these polymer modifiers results in a marked change in the electronic properties of the films, as measured by both carrier dynamics and overall device performance. The devices grown with the polymer poly(4-vinylpyridine) (PVP) show significantly enhanced power conversion efficiency from 16.9 ± 0.7% to 18.8 ± 0.8% (champion efficiency, 20.2%) from a reverse scan and stabilized champion efficiency from 17.5 to 19.1% [under a bias of 0.94 V and AM (air mass) 1.5-G, 1-sun illumination over 30 min] compared to controls without any passivation. Treating the perovskite film with PVP enables a of up to 1.16 V, which is among the best reported for a CHNHPbI perovskite solar cell and one of the lowest voltage deficits reported for any perovskite to date. In addition, perovskite solar cells treated with PVP show a long shelf lifetime of up to 90 days (retaining 85% of the initial efficiency) and increased by a factor of more than 20 compared to those without any polymer (degrading to 85% after ~4 days). Our work opens up a new class of chemical additives for improving perovskite performance and should pave the way toward improving perovskite solar cells for high efficiency and stability.
多晶钙钛矿薄膜的溶液处理会引入陷阱态，这会对其光电性能产生不利影响。受小分子表面活性剂用于改善钙钛矿光电性能的启发，我们展示了使用具有配位基团的聚合物来改善溶液处理的半导体薄膜的性能。这些聚合物改性剂的使用导致薄膜的电子性能发生显著变化，这通过载流子动力学和整体器件性能来衡量。用聚合物聚（4-乙烯基吡啶）（PVP）生长的器件显示，反向扫描时功率转换效率从16.9±0.7%显著提高到18.8±0.8%（最佳效率为20.2%），与未进行任何钝化处理的对照相比，在0.94 V偏压和AM（空气质量）1.5-G、1太阳光照30分钟的条件下，稳定的最佳效率从17.5%提高到19.1%。用PVP处理钙钛矿薄膜可实现高达1.16 V的开路电压，这是CHNH PbI钙钛矿太阳能电池报道的最佳值之一，也是迄今为止任何钙钛矿报道的最低电压损失之一。此外，用PVP处理的钙钛矿太阳能电池显示出长达90天的长保质期（保留初始效率的85%），与未使用任何聚合物的电池相比，保质期延长了20多倍（约4天后降至85%）。我们的工作开辟了一类用于改善钙钛矿性能的新型化学添加剂，应为提高钙钛矿太阳能电池的效率和稳定性铺平道路。
