9CPA is consisted of a carbazole terminal, a ethyl spacer and a carboxylic acid head anchor. Serving as hole selective layer (HSL) contact between the electrode and photoactive materials, the use of self-assembled monolayer (SAM) material 9CPA has been a great boost to device performance and operational stability in photovoltaic solar cell devices.
Comparing to 9CAA, 9CPA has a relatively longer alkyl spacer which allows higher monolayer density packing while the shorter chain can enhance the energy alignment of the SAMs with perovskite or active layer materials for better hole extraction. Narrow bandgap (≈1.25 eV) tin-lead (Sn-Pb) perovskite solar cells device based on 9CPA as the SAM interface demonstrated a power conversion efficiency (PCE) of 22.1% with an open voltage (VOC) of 0.89, compared to that of 20.9% with a VOC of 0.85 while 2PACz was used as SAM interface.
Serving as hole selective contact for organic solar cells and perovskite solar cells, 9CPA is an alternative to PEDOT:PSS with superior performance with the convenience of solution deposition at low concentration, i.e. 1 mM.
Typical processing solvents: Ethanol, methanol, IPA, DMF, THF Typical concentration: 1 mM - 1.0 mg/ml Typical processing procedure:
9CPA is dissolved in ethanol with a concentration of 0.3 mg/mL. The 9CPA solution is spin-coated on FTO for 30 s at the speed of 3000 rpm, and then annealed for 10 min at 100 ℃ (DOI 10.1002/adma.202312264).