2PACz, or (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (CAS 20999-38-6), is a widely used self-assembled monolayer (SAM) material for building hole selective layers in inverted (p-i-n) perovskite solar cells and organic solar cells. Its electron-rich carbazole core is linked to an ethyl phosphonic acid group that anchors the molecule to indium-tin-oxide (ITO) surfaces.
Once assembled on ITO, 2PACz shifts the electrode work function and influences the morphology of the active layer deposited on top. It can be used in place of PEDOT:PSS as a hole transport or extraction layer and is deposited from solution at low concentration, typically 1 mM. In perovskite devices it offers better band alignment with the perovskite valence band than PTAA and strongly reduces non-radiative recombination at the contact interface.
Reported results include near-lossless contacts in single-junction and tandem cells and an efficiency of 20.17% (19.79% certified) in PM6 : L8-BO : eC9 non-fullerene organic solar cells using a 2–6 nm 2PACz interlayer. Ossila supplies it as an off-white powder or crystals with purity > 98% (1H NMR).
- Hole selective layer on ITO in inverted p-i-n perovskite solar cells.
- Hole transport or extraction layer replacing PEDOT:PSS in non-fullerene polymer solar cells.
- Interface layer in perovskite/silicon and all-perovskite tandem solar cells.
- Interface management in indoor organic photovoltaics to suppress trap-assisted recombination and leakage current.
| Brand | Ossila |
|---|---|
| CAS number | 20999-38-6 |
| Molecular formula | C14H14NO3P |
| Purity | > 98% (1H NMR) |
| Category | — |
| Pack sizes | 500 mg, 1 g |
| Physical form | Off-white powder/crystals |
| Storage | — |
- Product code: M2425A1
- Molecular Weight: 275.24 g/mol
- Synonym: (2-(9H-carbazol-9-yl)ethyl)phosphonic acid
- Melting Point: 231 °C
- Absorption: λmax 340 nm (on ITO glass)
- HOMO/LUMO: HOMO = 5.6 eV, LUMO = 2.1 eV
- Typical Solvents: Ethanol, methanol, THF, IPA, DMF
- Typical Concentration: 1 mM (0.275 mg/ml) or 1.0 mg/ml
Typical processing uses ethanol, methanol, THF, IPA or DMF at 1 mM (0.275 mg/ml) or 1.0 mg/ml: 100 uL is spin-coated at 3000 rpm for 30 s, annealed for 10 min at 100 ℃ and cooled to room temperature. Consult the MSDS for safety information.
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