4PADCB, also called CbzNaph, is (4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (CAS 2882156-63-8), a self-assembled monolayer (SAM) molecule used as a hole transport or hole extraction layer in p-i-n perovskite solar cells, all-perovskite tandem cells and non-fullerene acceptor polymer solar cells. Its structure combines a fused dibenzo[c,g]carbazole head group, a butyl spacer and a phosphonic acid anchor that binds to the substrate.
Thanks to its large dipole moment, the molecule assembles into an ordered, dense monolayer on electrodes such as ITO. The electron-rich carbazole terminal contacts the active layer directly, raising the built-in potential, adjusting energy levels and the ITO work function, and influencing perovskite crystallization. It also improves wettability and film coverage, helping hole extraction and reducing nonradiative recombination at the interface. Compared with 4PACz, it shows a predominantly face-on orientation that favours charge transport.
4PADCB can replace PTAA, Spiro-MeOTAD or PEDOT:PSS and is deposited from solution at low concentrations such as 1 mM. Using a DMF/IPA co-solvent gave 24.98% device efficiency versus 22.73% with IPA alone. It is supplied as a white to off-white powder with purity > 98% (HPLC).
- Hole transport layer in inverted (p-i-n) perovskite solar cells as an alternative to PTAA or Spiro-MeOTAD.
- Hole-selective contact in all-perovskite tandem solar cells, including wide band gap subcells.
- Hole extraction layer in NFA-polymer organic solar cells as a PEDOT:PSS replacement.
- Work function tuning and surface modification of ITO electrodes.
| Brand | Ossila |
|---|---|
| CAS number | 2882156-63-8 |
| Molecular formula | C24H22NO3P |
| Purity | > 98% (HPLC) |
| Category | — |
| Pack sizes | 250 mg, 500 mg, 1 g |
| Physical form | White to off-white powder |
| Storage | — |
- Product code: M2446A1
- Molecular Weight: 403.41 g/mol
- HOMO/LUMO: HOMO = 5.35 eV, LUMO = 2.28 eV
- Synonyms: CbzNaph, (4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid
- Decomposition Temperature: Td = 378 °C
- Typical Solvents: IPA, IPA/DMF, ethanol
- Typical Concentration: 1.5 mg/ml, 1.0 mg/ml, 0.5 mg/ml, or 1 mM
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