Morais Eliane A, Lemes Maykon A, Souza Natalilian R S, Ito Amando Siuiti, Duarte Evandro L, Silva Ronaldo S, Brochsztain Sergio, Souza Jose A
Center for Human and Natural Sciences, Federal University of ABC, Santo André 09210-580, São Paulo, Brazil.
Engineering, Modeling and Applied Social Sciences Center, Federal University of ABC, Santo André 09280-560, Brazil.
ACS Omega. 2024 May 9;9(20):22296-22304. doi: 10.1021/acsomega.4c01651. eCollection 2024 May 21.
Halide perovskites have attracted much attention for energy conversion. However, efficient charge carrier generation, separation, and mobility remain the most important issues limiting the higher efficiency of solar cells. An efficient interfacial charge transfer process associated with exciton dynamics between all-inorganic CsPbBr nanocrystals and organic electron acceptors has been suggested. We observed a strong PL quenching of 78% in thin films when silane-functionalized naphthalenediimides (SNDI), used as electron-acceptors, are anchored on CsPbBr nanocrystals. Optical and structural characterizations confirm the charge transfer process without QDs degradation. The issue of whether these transferred charges are indeed available for utilization in solar cells remains uncertain. Our results reveal that the CsPbBr nanocrystals capped with these electron-acceptor SNDI molecules show a drastic increase in the electrical resistance and the absence of a photoconductivity effect. The results suggest charge transfer followed by strong localization of the charge carriers, preventing their extraction toward the electrodes of solar cell devices. We hope that this crucial aspect to attract attention and unveil a potential mechanism for charge delocalization, which could, in turn, lead to a groundbreaking enhancement in solar cell efficiency.
卤化物钙钛矿在能量转换方面备受关注。然而，高效的电荷载流子产生、分离和迁移率仍然是限制太阳能电池实现更高效率的最重要问题。有人提出了一种与全无机CsPbBr纳米晶体和有机电子受体之间的激子动力学相关的高效界面电荷转移过程。当用作电子受体的硅烷功能化萘二酰亚胺（SNDI）锚定在CsPbBr纳米晶体上时，我们观察到薄膜中的光致发光强烈猝灭了78%。光学和结构表征证实了电荷转移过程，且量子点没有降解。这些转移的电荷是否确实可用于太阳能电池的利用这一问题仍不确定。我们的结果表明，用这些电子受体SNDI分子包覆的CsPbBr纳米晶体的电阻急剧增加，且不存在光电导效应。结果表明电荷转移后电荷载流子强烈局域化，阻止了它们向太阳能电池器件电极的提取。我们希望这一关键方面能引起关注，并揭示电荷离域的潜在机制，这反过来可能会导致太阳能电池效率的突破性提高。
