自组装单分子层(SAM)已广泛用作倒置钙钛矿太阳能电池(PSC)中的底部接触空穴选择层(HSL)。除了调控电学特性之外，基于SAM的分子工程还提供了调控钙钛矿埋底界面的机会。
鉴于此，香港城市大学Alex Jen团队通过合理的不对称SAM分子设计成功引入了路易斯碱性氧原子和硫原子，获得了两种新型多功能SAM分子：CbzBF和CbzBT。单晶结构和器件界面表征表明，该设计成功实现了SAM分子堆积增强、更有效的ITO功函数的调节和掩埋界面钝化。因此，采用CbzBT的冠军器件表现出24.04%的出色功率转换效率 (PCE)、84.41% 的高填充因子以及提升的稳定性。
这项工作证明了在SAM分子中引入缺陷钝化杂环基团以帮助钝化PSC中的界面缺陷的可行性。从分子设计策略中获得的见解将加速用于高效PSC的新型多功能SAM HSL的开发。
Fig. 1 Molecular structures, calculated dipole moments and HOMO energy levels of CbzPh, CbzBF, and CbzBT.
Fig. 2 The molecular packing patterns in single crystals of the π-scaffolds of a) CbzPh (7H-benzo[c]carbazole), b) CbzBF (5H-benzofuro[3,2-c]carbazole), and c) CbzBT (5H-benzo[4,5]thieno[3,2-c]carbazole).
Fig. 3 a) The SEM images, b) XRD patterns (Here * denotes the diffraction peak of PbI2, and # denotes the diffraction peak of ITO), c) PL spectra and d) TRPL spectra (the direction of incident light comes from the perovskite side) of perovskite films deposited on CbzPh, CbzBF and CbzBT HSL.
Fig. 4 a) Device architecture of the inverted PSCs; b) current density–voltage (J–V) characteristics; c) box plots of PCEs of the PSCs employing SAM-modified substrates of CbzPh, CbzBF and CbzBT; d)–f) device characteristics of d) J–V sweeps, e) EQE and f) stabilized power output (SPO) of the champion device employing CbzBT HSL.
Wenlin Jiang., Ming Liu., et al. Rational molecular design of multifunctional self-assembled monolayers for efficient hole selection and buried interface passivation in inverted perovskite solar cells.Chem. Sci., 2024
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