Poly(N,N'-bis-4-butylphenyl-N,N'-bisphenyl)benzidine, also known as polyTPD or Poly-TPD (CAS number 472960-35-3), is an excellent hole transport layer material used in photovoltaics such as perovskite solar cells. It has also proven polyTPD is a promising HTL candidate in multilayer WPLEDs because its HOMO level 5.2 eV is very close to the work function of the indium tin oxide ITO/PEDOT:PSS anode.

As the highest occupied molecular orbital (HOMO) of polyTPD matches well with the VB of the perovskite, which allows for a good transport of holes towards the polyTPD, it is a popular semiconducting material candidate that is used in the HTL of the perovskite structures. And also as the LUMO of polyTPD is significantly closer to vacuum compared with that of the perovskite CB, polyTPD efficiently blocks the flow of electrons [5].

Like PTAA, polyTPD is one of the family members of poly(triaryl)amines.

General Information

Chemical Structure

Device Structure(s)

Device Structure	ITO/PEDOT:PSS/PVK:polyTPD (1:1 wt%) 50 nm/PFO:MEH-PPV*(95.5:0.5 wt%) 70 nm/Ca/Al [4]
Colour	White
Max. Luminance	~ 5,000 cd/m2
Max. Current Efficiency	3.15 cd/A

Device Structure	ITO/P(VDF-TrFE-CFE) (1000 nm)/poly-TPD:F4TCNQ (7%, 70 nm)/ PVK:OXD-7:Ir(ppy)3 (150 nm)/TmPyPB(40 nm)/LiF(1 nm)/Al(150 nm) [7]
Colour	Green
Max. Luminance	13,800 cd/m2
Max. Current Efficiency	76.2 cd/A
Max. Power Efficiency	17.1 lm W−1

Device Structure	ITO/PEDOT:PSS(30 nm)/poly-TPD(40 nm)/DNA-CTMA*(20 nm)/PFO:MEH-PPV (70 nm)/Cs2CO3(1 – 2 nm)/Al [2]
Colour	White
Max. Luminance	10,500 cd/m2
Max. Current Efficiency	10 cd/A

*For chemical structure informations please refer to the cited references

PolyTPD as a HTL to compare with PEDOT:PSS a) 1.0 V in the supporting information and 1.1 V in the body text of the cited lit. [6]