Ti-Oxo Clusters with Peripheral Alkyl Groups as Cathode Interlayers for Efficient Organic Solar Cells

Abstract

Three independent Ti-oxo clusters (TOCs) that contain 6, 8, and 12 Ti atoms in the cores and alkyl groups on the surface were developed as cathode interlayers in bulk-heterojunction organic solar cells (OSCs). These TOCs have precise chemical structures with a single crystal, excellent solubility in methanol, and well-aligned work function. Smooth films can be facilely obtained by spin-casting their solution on top of the active layer. Therefore, they can be used as an interlayer in OSCs to provide a high power conversion efficiency (17.29%). Further studies reveal that these TOCs can not only reduce the work function of the silver electrode to provide better energy level alignment but also exhibit a significant n-doping effect with the non-fullerene acceptors to facilitate efficient electron extraction and transport. Our results demonstrate that TOCs as semiconductors have great potential application in OSCs.

Functional Ligand-Decorated ZnO Nanoparticles as Cathode Interlayers for Efficient Organic Solar Cells

“…To further evaluate the potential of ZnO–N as CIL in OSCs, we conducted atomic force microscopy (AFM), ultraviolet photoelectron spectroscopy (UPS), electron spin resonance (ESR), and electron mobility measurements. − Figure a–d shows the AFM height and phase images of ZnO and ZnO–N films, respectively. The films of ZnO and ZnO–N deposited on the PM6: TP-4Cl (Figure S5) blends are selected for AFM experiment.…”

Organic–inorganic hybrid cathode interlayer materials for efficient organic solar cells

“…7b), which are soluble in methanol, can provide high PCEs by using these bare TOCs without further modication. 148 These results clearly suggest that TOCs can be a novel kind of CILs with signicant prospects for efficient OSCs, while both the Ti-oxo cores and surface organic groups play crucial roles in their functions in OSC devices (Table 5).…”

Hole/Electron Transporting Materials for Nonfullerene Organic Solar Cells

“…[30] With increasing the temperature from 75 to 125 and 200 °C, the WF was lowered from À 3.7 eV of LT TIAA to À 3.9 eV of MT TIAA and À 4.1 eV of HT TIAA, owing to the 16 , denoted as Ti12) Ti atoms in the cores and alkyl groups on the surface as ETLs. [31] These TOCs have precise chemical structures with a single crystal, excellent solubility in methanol, well-aligned WF and could form smooth films on top of the active layer. As a consequence, high efficiencies of 13.06 % and 17.29 % were obtained by using the blends of PM6: IT-4F and PM6:BTP-4Cl, respectively.…”

“…Li et al. developed a series of Ti‐oxo clusters (TOCs) that contain 6 (Ti 6 O 6 ( n PrCOO) 6 (O i Pr) 6 , denoted as Ti6), 8 (Ti 8 O 8 ( t BuCOO) 16 , denoted as Ti8), and 12 (Ti 8 O 8 ( t BuCOO) 16 , denoted as Ti12) Ti atoms in the cores and alkyl groups on the surface as ETLs [31] . These TOCs have precise chemical structures with a single crystal, excellent solubility in methanol, well‐aligned WF and could form smooth films on top of the active layer.…”