Ph-4PACz, featuring a rotatory phenyl group, aims to enhance steric hindrance and diminish the intermolecular interactions between molecules. Compared to the well-known crystalline Me-4PACz, Ph-4PACz is amorphous, possessing a large dipole moment (2.32 D). The electron withdrawing phenyl groups reduce the electron density of the carbazole core and deepen the HOMO and Fermi level of Ph-4PACz compared to that of the Me-4PACz (with electron-donating methyl groups).

With high polarity, Ph-4PACz is designed to improve the band alignment and minimize the energy loss, demonstrating an open-circuit voltage (VOC) as high as 1.2 V for 1.55 eV perovskite. Alumina nanoparticles (Al2O3-NPs) can further smooth the interface between the Ph-4PACz self-assembled monolayer and the FTO substrate, leading to a conformal perovskite film with almost no voids in the buried interface. The smooth interface and conformal active layer film promote low exciton binding energy, fast hot-carrier extraction and low non-radiative recombination. Consequently, a large-area (1 cm2) device based on Ph-4PACz as the hole extraction layer gains a power conversion efficiency (PCE) of 24.61%.

Ph-4PACz works well for both small and large area devices. Serving as hole selective contact for organic solar cells and perovskite solar cells, Ph-4PACz is an alternative to PEDOT:PSS with superior performance and the convenience of solution deposition at low concentration, i.e. 1 mM.

Solution Processing Procedure

Typical processing solvents: Anhydrous ethanol (IPA, IPA/DMF are also superior solvents)
Typical concentration: 0.1 mM to 1 mM
Typical processing procedure: Ph-4PACz (0.1 mM in MeOH) solution is deposited onto the centre of the substrate surface and spin-coated for 30 s at the speed of 3000 rpm (DOI: 10.1002/aenm.202303941).

General Information

Product Details

Chemical Structure